E. Robutti

Based on the full BaBar data sample, we report improved measurements of the ratios R(D(*)) = B(B -> D(*) Tau Nu)/B(B -> D(*) l Nu), where l is either e or mu. These ratios are sensitive to new physics contributions in the form of a charged Higgs boson. We measure R(D) = 0.440 +- 0.058 +- 0.042 and R(D*) = 0.332 +- 0.024 +- 0.018, which exceed the Standard Model expectations by 2.0 sigma and 2.7 sigma, respectively. Taken together, our results disagree with these expectations at the 3.4 sigma level. This excess cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model. Kinematic distributions presented here exclude large portions of the more general type III two-Higgs-doublet model, but there are solutions within this model compatible with the results.

Dark sectors charged under a new Abelian force have recently received much attention in the context of dark matter models. These models introduce a light new mediator, the so-called dark photon (A'), connecting the dark sector to the Standard Model. We present a search for a dark photon in the reaction e+e- -> gamma A', A'-> e+e-, mu+mu- using 514 fb-1 of data collected with the BABAR detector. We do not observe a significant signal and we set 90% confidence level upper limits on the mixing strength between the photon and dark photon at the level of 10^-4 - 10^-3 for dark photon masses in the range 0.02 - 10.2 GeV. We further constrain the range of the parameter space favored by interpretations of the discrepancy between the calculated and measured anomalous magnetic moment of the muon.

TOTEM has measured the differential cross-section for elastic proton-proton scattering at the LHC energy of analysing data from a short run with dedicated large-β* optics. A single exponential fit with a slope B=(20.1±0.2stat±0.3syst) GeV−2 describes the range of the four-momentum transfer squared |t| from 0.02 to 0.33 GeV2. After the extrapolation to |t|=0, a total elastic scattering cross-section of (24.8±0.2stat±1.2syst) mb was obtained. Applying the optical theorem and using the luminosity measurement from CMS, a total proton-proton cross-section of (98.3±0.2stat±2.8syst) mb was deduced which is in good agreement with the expectation from the overall fit of previously measured data over a large range of center-of-mass energies. From the total and elastic pp cross-section measurements, an inelastic pp cross-section of was inferred.

At the LHC energy of , under various beam and background conditions, luminosities, and Roman Pot positions, TOTEM has measured the differential cross-section for proton-proton elastic scattering as a function of the four-momentum transfer squared t. The results of the different analyses are in excellent agreement demonstrating no sizeable dependence on the beam conditions. Due to the very close approach of the Roman Pot detectors to the beam center (≈5σbeam) in a dedicated run with β* = 90 m, |t|-values down to 5·10−3 GeV2 were reached. The exponential slope of the differential elastic cross-section in this newly explored |t|-region remained unchanged and thus an exponential fit with only one constant B = (19.9 ± 0.3) GeV−2 over the large |t|-range from 0.005 to 0.2 GeV2 describes the differential distribution well. The high precision of the measurement and the large fit range lead to an error on the slope parameter B which is remarkably small compared to previous experiments. It allows a precise extrapolation over the non-visible cross-section (only 9%) to t = 0. With the luminosity from CMS, the elastic cross-section was determined to be (25.4 ± 1.1) mb, and using in addition the optical theorem, the total pp cross-section was derived to be (98.6 ± 2.2) mb. For model comparisons the t-distributions are tabulated including the large |t|-range of the previous measurement (TOTEM Collaboration (Antchev G. et al), EPL, 95 (2011) 41001).

The TOTEM collaboration has measured the proton-proton total cross section at √s=8 TeV using a luminosity-independent method. In LHC fills with dedicated beam optics, the Roman pots have been inserted very close to the beam allowing the detection of ~90% of the nuclear elastic scattering events. Simultaneously the inelastic scattering rate has been measured by the T1 and T2 telescopes. By applying the optical theorem, the total proton-proton cross section of (101.7±2.9) mb has been determined, well in agreement with the extrapolation from lower energies. This method also allows one to derive the luminosity-independent elastic and inelastic cross sections: σ(el)=(27.1±1.4) mb; σ(inel)=(74.7±1.7) mb.

The TOTEM experiment has made a precise measurement of the elastic proton–proton differential cross-section at the centre-of-mass energy s=8TeV based on a high-statistics data sample obtained with the β⁎=90m optics. Both the statistical and systematic uncertainties remain below 1%, except for the t-independent contribution from the overall normalisation. This unprecedented precision allows to exclude a purely exponential differential cross-section in the range of four-momentum transfer squared 0.027<|t|<0.2GeV2 with a significance greater than 7σ. Two extended parametrisations, with quadratic and cubic polynomials in the exponent, are shown to be well compatible with the data. Using them for the differential cross-section extrapolation to t=0, and further applying the optical theorem, yields total cross-section estimates of (101.5±2.1)mb and (101.9±2.1)mb, respectively, in agreement with previous TOTEM measurements.

The TOTEM Experiment will measure the total pp cross-section with the luminosity-independent method and study elastic and diffractive scattering at the LHC. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the interaction point IP5, two tracking telescopes, T1 and T2, will be installed on each side in the pseudorapidity region 3.1 ⩽ |η| ⩽ 6.5, and Roman Pot stations will be placed at distances of ±147 m and ±220 m from IP5. Being an independent experiment but technically integrated into CMS, TOTEM will first operate in standalone mode to pursue its own physics programme and at a later stage together with CMS for a common physics programme. This article gives a description of the TOTEM apparatus and its performance.

Proton-proton elastic scattering has been measured by the TOTEM experiment at the CERN Large Hadron Collider at in dedicated runs with the Roman Pot detectors placed as close as seven times the transverse beam size (σbeam) from the outgoing beams. After careful study of the accelerator optics and the detector alignment, |t|, the square of four-momentum transferred in the elastic scattering process, has been determined with an uncertainty of . In this letter, first results of the differential cross-section are presented covering a |t|-range from 0.36 to 2.5 GeV2. The differential cross-section in the range 0.36 < |t| < 0.47 GeV2 is described by an exponential with a slope parameter B = (23.6 ± 0.5stat ± 0.4syst) GeV−2, followed by a significant diffractive minimum at |t| = (0.53 ± 0.01stat ± 0.01syst) GeV2. For |t|-values larger than ∼1.5 GeV2, the cross-section exhibits a power law behaviour with an exponent of −7.8 ± 0.3stat ± 0.1syst. When compared to predictions based on the different available models, the data show a strong discriminative power despite the small t-range covered.

We search for the flavor-changing neutral-current decays $B\ensuremath{\rightarrow}{K}^{(*)}\ensuremath{\nu}\overline{\ensuremath{\nu}}$, and the invisible decays $J/\ensuremath{\psi}\ensuremath{\rightarrow}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ and $\ensuremath{\psi}(2S)\ensuremath{\rightarrow}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ via $B\ensuremath{\rightarrow}{K}^{(*)}J/\ensuremath{\psi}$ and $B\ensuremath{\rightarrow}{K}^{(*)}\ensuremath{\psi}(2S)$, respectively, using a data sample of $471\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected by the BABAR experiment. We fully reconstruct the hadronic decay of one of the $B$ mesons in the $\ensuremath{\Upsilon}(4S)\ensuremath{\rightarrow}B\overline{B}$ decay, and search for the $B\ensuremath{\rightarrow}{K}^{(*)}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ decay in the rest of the event. We observe no significant excess of signal decays over background and report branching fraction upper limits of $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{K}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}})&lt;3.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, $\mathcal{B}({B}^{0}\ensuremath{\rightarrow}{K}^{0}\ensuremath{\nu}\overline{\ensuremath{\nu}})&lt;8.1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{K}^{*+}\ensuremath{\nu}\overline{\ensuremath{\nu}})&lt;11.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, $\mathcal{B}({B}^{0}\ensuremath{\rightarrow}{K}^{*0}\ensuremath{\nu}\overline{\ensuremath{\nu}})&lt;9.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, and combined upper limits of $\mathcal{B}(B\ensuremath{\rightarrow}K\ensuremath{\nu}\overline{\ensuremath{\nu}})&lt;3.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ and $\mathcal{B}(B\ensuremath{\rightarrow}{K}^{*}\ensuremath{\nu}\overline{\ensuremath{\nu}})&lt;7.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, all at the 90% confidence level. For the invisible quarkonium decays, we report branching fraction upper limits of $\mathcal{B}(J/\ensuremath{\psi}\ensuremath{\rightarrow}\ensuremath{\nu}\overline{\ensuremath{\nu}})&lt;3.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ and $\mathcal{B}(\ensuremath{\psi}(2S)\ensuremath{\rightarrow}\ensuremath{\nu}\overline{\ensuremath{\nu}})&lt;15.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ at the 90% confidence level. Using the improved kinematic resolution achieved from hadronic reconstruction, we also provide partial branching fraction limits for the $B\ensuremath{\rightarrow}{K}^{(*)}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ decays over the full kinematic spectrum.

The TOTEM experiment at the CERN LHC has measured elastic proton–proton scattering at the centre-of-mass energy $$\sqrt{s}=8\,$$ TeV and four-momentum transfers squared, |t|, from $$6\times 10^{-4}$$ to 0.2 GeV $$^{2}$$ . Near the lower end of the t-interval the differential cross-section is sensitive to the interference between the hadronic and the electromagnetic scattering amplitudes. This article presents the elastic cross-section measurement and the constraints it imposes on the functional forms of the modulus and phase of the hadronic elastic amplitude. The data exclude the traditional Simplified West and Yennie interference formula that requires a constant phase and a purely exponential modulus of the hadronic amplitude. For parametrisations of the hadronic modulus with second- or third-order polynomials in the exponent, the data are compatible with hadronic phase functions giving either central or peripheral behaviour in the impact parameter picture of elastic scattering. In both cases, the $$\rho $$ -parameter is found to be $$0.12 \pm 0.03$$ . The results for the total hadronic cross-section are $$\sigma _\mathrm{tot} = (102.9 \pm 2.3)$$ mb and $$(103.0 \pm 2.3)$$ mb for central and peripheral phase formulations, respectively. Both are consistent with previous TOTEM measurements.

We present measurements of Collins asymmetries in the inclusive process e+e- -->pi pi X, where pi stands for charged pions, at a center-of-mass energy of 10.6 GeV. We use a data sample of 468 fb-1 collected by the BABAR experiment at the PEP-II B factory at SLAC, and consider pairs of charged pions produced in opposite hemispheres of hadronic events. We observe clear asymmetries in the distributions of the azimuthal angles in two distinct reference frames. We study the dependence of the asymmetry on several kinematic variables, finding that it increases with increasing pion momentum and momentum transverse to the analysis axis, and with increasing angle between the thrust and beam axis.

The TOTEM collaboration has measured the proton–proton total cross section at $$\sqrt{s}=13~\hbox {TeV}$$ with a luminosity-independent method. Using dedicated $$\beta ^{*}=90~\hbox {m}$$ beam optics, the Roman Pots were inserted very close to the beam. The inelastic scattering rate has been measured by the T1 and T2 telescopes during the same LHC fill. After applying the optical theorem the total proton–proton cross section is $$\sigma _\mathrm{tot}=(110.6~\pm ~3.4$$ ) mb, well in agreement with the extrapolation from lower energies. This method also allows one to derive the luminosity-independent elastic and inelastic cross sections: $$\sigma _\mathrm{el}=(31.0~\pm ~1.7)~\hbox {mb}$$ and $$\sigma _\mathrm{inel}=(79.5~\pm ~1.8)~\hbox {mb}$$ .

Abstract The TOTEM experiment at the LHC has performed the first measurement at $$\sqrt{s} = 13\,\mathrm{TeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msqrt><mml:mi>s</mml:mi></mml:msqrt><mml:mo>=</mml:mo><mml:mn>13</mml:mn><mml:mspace /><mml:mi>TeV</mml:mi></mml:mrow></mml:math> of the $$\rho $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>ρ</mml:mi></mml:math> parameter, the real to imaginary ratio of the nuclear elastic scattering amplitude at $$t=0$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>t</mml:mi><mml:mo>=</mml:mo><mml:mn>0</mml:mn></mml:mrow></mml:math> , obtaining the following results: $$\rho = 0.09 \pm 0.01$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>ρ</mml:mi><mml:mo>=</mml:mo><mml:mn>0.09</mml:mn><mml:mo>±</mml:mo><mml:mn>0.01</mml:mn></mml:mrow></mml:math> and $$\rho = 0.10 \pm 0.01$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>ρ</mml:mi><mml:mo>=</mml:mo><mml:mn>0.10</mml:mn><mml:mo>±</mml:mo><mml:mn>0.01</mml:mn></mml:mrow></mml:math> , depending on different physics assumptions and mathematical modelling. The unprecedented precision of the $$\rho $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>ρ</mml:mi></mml:math> measurement, combined with the TOTEM total cross-section measurements in an energy range larger than $$10\,\mathrm{TeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>10</mml:mn><mml:mspace /><mml:mi>TeV</mml:mi></mml:mrow></mml:math> (from 2.76 to $$13\,\mathrm{TeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>13</mml:mn><mml:mspace /><mml:mi>TeV</mml:mi></mml:mrow></mml:math> ), has implied the exclusion of all the models classified and published by COMPETE. The $$\rho $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>ρ</mml:mi></mml:math> results obtained by TOTEM are compatible with the predictions, from other theoretical models both in the Regge-like framework and in the QCD framework, of a crossing-odd colourless 3-gluon compound state exchange in the t -channel of the proton–proton elastic scattering. On the contrary, if shown that the crossing-odd 3-gluon compound state t -channel exchange is not of importance for the description of elastic scattering, the $$\rho $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>ρ</mml:mi></mml:math> value determined by TOTEM would represent a first evidence of a slowing down of the total cross-section growth at higher energies. The very low-| t | reach allowed also to determine the absolute normalisation using the Coulomb amplitude for the first time at the LHC and obtain a new total proton–proton cross-section measurement $$\sigma _{\mathrm{tot}} = (110.3 \pm 3.5)\,\mathrm{mb}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>σ</mml:mi><mml:mi>tot</mml:mi></mml:msub><mml:mo>=</mml:mo><mml:mrow><mml:mo>(</mml:mo><mml:mn>110.3</mml:mn><mml:mo>±</mml:mo><mml:mn>3.5</mml:mn><mml:mo>)</mml:mo></mml:mrow><mml:mspace /><mml:mi>mb</mml:mi></mml:mrow></mml:math> , completely independent from the previous TOTEM determination. Combining the two TOTEM results yields $$\sigma _{\mathrm{tot}} = (110.5 \pm 2.4)\,\mathrm{mb}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>σ</mml:mi><mml:mi>tot</mml:mi></mml:msub><mml:mo>=</mml:mo><mml:mrow><mml:mo>(</mml:mo><mml:mn>110.5</mml:mn><mml:mo>±</mml:mo><mml:mn>2.4</mml:mn><mml:mo>)</mml:mo></mml:mrow><mml:mspace /><mml:mi>mb</mml:mi></mml:mrow></mml:math> .

A precise measurement of the cross section for the process e+e- --> K+K-(gamma) from threshold to an energy of 5 GeV is obtained with the initial-state radiation (ISR) method using 232 fb^{-1} of data collected with the BaBar detector at e+e- center-of-mass energies near 10.6 GeV. The measurement uses the effective ISR luminosity determined from the e+e- --> mu+mu-(gamma)gamma_ISR process with the same data set. The corresponding lowest-order contribution to the hadronic vacuum polarization term in the muon magnetic anomaly is found to be a_mu^{KK, LO}=(22.93 +- 0.18_{stat} +- 0.22_{syst}) * 10^{-10}. The charged kaon form factor is extracted and compared to previous results. Its magnitude at large energy significantly exceeds the asymptotic QCD prediction, while the measured slope is consistent with the prediction.

Abstract The TOTEM collaboration has measured the elastic proton-proton differential cross section $$\mathrm{d}\sigma /\mathrm{d}t$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>d</mml:mi><mml:mi>σ</mml:mi><mml:mo>/</mml:mo><mml:mi>d</mml:mi><mml:mi>t</mml:mi></mml:mrow></mml:math> at $$\sqrt{s}=13$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msqrt><mml:mi>s</mml:mi></mml:msqrt><mml:mo>=</mml:mo><mml:mn>13</mml:mn></mml:mrow></mml:math> TeV LHC energy using dedicated $$\beta ^{*}=90$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mi>β</mml:mi><mml:mrow><mml:mrow /><mml:mo>∗</mml:mo></mml:mrow></mml:msup><mml:mo>=</mml:mo><mml:mn>90</mml:mn></mml:mrow></mml:math> m beam optics. The Roman Pot detectors were inserted to 10 $$\sigma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>σ</mml:mi></mml:math> distance from the LHC beam, which allowed the measurement of the range [0.04 GeV $$^{2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow /><mml:mn>2</mml:mn></mml:msup></mml:math> ; 4 GeV $$^{2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow /><mml:mn>2</mml:mn></mml:msup></mml:math> $$]$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mo>]</mml:mo></mml:math> in four-momentum transfer squared | t |. The efficient data acquisition allowed to collect about 10 $$^{9}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow /><mml:mn>9</mml:mn></mml:msup></mml:math> elastic events to precisely measure the differential cross-section including the diffractive minimum (dip), the subsequent maximum (bump) and the large-| t | tail. The average nuclear slope has been found to be $$B=(20.40 \pm 0.002^{\mathrm{stat}} \pm 0.01^{\mathrm{syst}})~$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>B</mml:mi><mml:mo>=</mml:mo><mml:mo>(</mml:mo><mml:mn>20.40</mml:mn><mml:mo>±</mml:mo><mml:mn>0</mml:mn><mml:mo>.</mml:mo><mml:msup><mml:mn>002</mml:mn><mml:mi>stat</mml:mi></mml:msup><mml:mo>±</mml:mo><mml:mn>0</mml:mn><mml:mo>.</mml:mo><mml:msup><mml:mn>01</mml:mn><mml:mi>syst</mml:mi></mml:msup><mml:mo>)</mml:mo><mml:mspace /></mml:mrow></mml:math> GeV $$^{-2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow /><mml:mrow><mml:mo>-</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:msup></mml:math> in the | t |-range 0.04–0.2 GeV $$^{2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow /><mml:mn>2</mml:mn></mml:msup></mml:math> . The dip position is $$|t_{\mathrm{dip}}|=(0.47 \pm 0.004^{\mathrm{stat}} \pm 0.01^{\mathrm{syst}})~$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mrow><mml:mo>|</mml:mo></mml:mrow><mml:msub><mml:mi>t</mml:mi><mml:mi>dip</mml:mi></mml:msub><mml:mrow><mml:mo>|</mml:mo><mml:mo>=</mml:mo></mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mn>0.47</mml:mn><mml:mo>±</mml:mo><mml:mn>0</mml:mn><mml:mo>.</mml:mo><mml:msup><mml:mn>004</mml:mn><mml:mi>stat</mml:mi></mml:msup><mml:mo>±</mml:mo><mml:mn>0</mml:mn><mml:mo>.</mml:mo><mml:msup><mml:mn>01</mml:mn><mml:mi>syst</mml:mi></mml:msup><mml:mo>)</mml:mo></mml:mrow><mml:mspace /></mml:mrow></mml:math> GeV $$^{2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow /><mml:mn>2</mml:mn></mml:msup></mml:math> . The differential cross section ratio at the bump vs. at the dip $$R=1.77\pm 0.01^{\mathrm{stat}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>R</mml:mi><mml:mo>=</mml:mo><mml:mn>1.77</mml:mn><mml:mo>±</mml:mo><mml:mn>0</mml:mn><mml:mo>.</mml:mo><mml:msup><mml:mn>01</mml:mn><mml:mi>stat</mml:mi></mml:msup></mml:mrow></mml:math> has been measured with high precision. The series of TOTEM elastic pp measurements show that the dip is a permanent feature of the pp differential cross-section at the TeV scale.

Abstract The proton–proton elastic differential cross section $${\mathrm{d}}\sigma /{\mathrm{d}}t$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>d</mml:mi><mml:mi>σ</mml:mi><mml:mo>/</mml:mo><mml:mi>d</mml:mi><mml:mi>t</mml:mi></mml:mrow></mml:math> has been measured by the TOTEM experiment at $$\sqrt{s}=2.76\hbox { TeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msqrt><mml:mi>s</mml:mi></mml:msqrt><mml:mo>=</mml:mo><mml:mn>2.76</mml:mn><mml:mspace /><mml:mtext>TeV</mml:mtext></mml:mrow></mml:math> energy with $$\beta ^{*}=11\hbox { m}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mi>β</mml:mi><mml:mrow><mml:mrow /><mml:mo>∗</mml:mo></mml:mrow></mml:msup><mml:mo>=</mml:mo><mml:mn>11</mml:mn><mml:mspace /><mml:mtext>m</mml:mtext></mml:mrow></mml:math> beam optics. The Roman Pots were inserted to 13 times the transverse beam size from the beam, which allowed to measure the differential cross-section of elastic scattering in a range of the squared four-momentum transfer (| t |) from 0.36 to $$0.74\hbox { GeV}^{2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>0.74</mml:mn><mml:mspace /><mml:msup><mml:mtext>GeV</mml:mtext><mml:mn>2</mml:mn></mml:msup></mml:mrow></mml:math> . The differential cross-section can be described with an exponential in the | t |-range between 0.36 and $$0.54\hbox { GeV}^{2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>0.54</mml:mn><mml:mspace /><mml:msup><mml:mtext>GeV</mml:mtext><mml:mn>2</mml:mn></mml:msup></mml:mrow></mml:math> , followed by a diffractive minimum (dip) at $$|t_{\mathrm{dip}}|=(0.61\pm 0.03)\hbox { GeV}^{2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mrow><mml:mo>|</mml:mo></mml:mrow><mml:msub><mml:mi>t</mml:mi><mml:mi>dip</mml:mi></mml:msub><mml:mrow><mml:mo>|</mml:mo><mml:mo>=</mml:mo><mml:mrow><mml:mo>(</mml:mo><mml:mn>0.61</mml:mn><mml:mo>±</mml:mo><mml:mn>0.03</mml:mn><mml:mo>)</mml:mo></mml:mrow><mml:mspace /></mml:mrow><mml:msup><mml:mtext>GeV</mml:mtext><mml:mn>2</mml:mn></mml:msup></mml:mrow></mml:math> and a subsequent maximum (bump). The ratio of the $${\mathrm{d}}\sigma /{\mathrm{d}}t$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>d</mml:mi><mml:mi>σ</mml:mi><mml:mo>/</mml:mo><mml:mi>d</mml:mi><mml:mi>t</mml:mi></mml:mrow></mml:math> at the bump and at the dip is $$1.7\pm 0.2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>1.7</mml:mn><mml:mo>±</mml:mo><mml:mn>0.2</mml:mn></mml:mrow></mml:math> . When compared to the proton–antiproton measurement of the D0 experiment at $$\sqrt{s} = 1.96\hbox { TeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msqrt><mml:mi>s</mml:mi></mml:msqrt><mml:mo>=</mml:mo><mml:mn>1.96</mml:mn><mml:mspace /><mml:mtext>TeV</mml:mtext></mml:mrow></mml:math> , a significant difference can be observed. Under the condition that the effects due to the energy difference between TOTEM and D0 can be neglected, the result provides evidence for the exchange of a colourless C-odd three-gluon compound state in the t -channel of the proton–proton and proton–antiproton elastic scattering.

The cross section for the reaction $\overline{p}\stackrel{\ensuremath{\rightarrow}}{p}{e}^{+}{e}^{\ensuremath{-}}$ has been measured at $s=8.8,$ $10.8,$ $12.4,$ $13.1,$ and $14.4 {\mathrm{GeV}}^{2}$ by Fermilab experiment E835. A non-magnetic spectrometer is used to identify the ${e}^{+}{e}^{\ensuremath{-}}$ final states generated by the antiproton beam intersecting an internal hydrogen gas jet target. From the analysis of the 144 observed events, new high-precision measurements of the proton magnetic form factor for timelike momentum transfers are obtained.

This report is the result of the collaboration and research effort of the Quarkonium Working Group over the last three years. It provides a comprehensive overview of the state of the art in heavy-quarkonium theory and experiment, covering quarkonium spectroscopy, decay, and production, the determination of QCD parameters from quarkonium observables, quarkonia in media, and the effects on quarkonia of physics beyond the Standard Model. An introduction to common theoretical and experimental tools is included. Future opportunities for research in quarkonium physics are also discussed.

The e+ e- --> p anti-p cross section and the proton magnetic form factor have been measured in the center-of-mass energy range from 3.0 to 6.5 GeV using the initial-state-radiation technique with an undetected photon. This is the first measurement of the form factor at energies higher than 4.5 GeV. The analysis is based on 469 fb-1 of integrated luminosity collected with the BABAR detector at the PEP-II collider at e+e- center-of-mass energies near 10.6 GeV. The branching fractions for the decays J/psi --> p anti-p and psi(2S) --> p anti-p have also been measured.

We study the processes $e^+ e^-\to K_S^0 K_L^0 \gamma$, $K_S^0 K_L^0 \pi^+\pi^-\gamma$, $K_S^0 K_S^0 \pi^+\pi^-\gamma$, and $K_S^0 K_S^0 K^+K^-\gamma$, where the photon is radiated from the initial state, providing cross section measurements for the hadronic states over a continuum of center-of-mass energies. The results are based on 469 fb$^{-1}$ of data collected with the BaBar detector at SLAC. We observe the $\phi(1020)$ resonance in the $K_S^0 K_L^0$ final state and measure the product of its electronic width and branching fraction with about 3% uncertainty. We present a measurement of the $e^+ e^-\to K_S^0 K_L^0 $ cross section in the energy range from 1.06 to 2.2 GeV and observe the production of a resonance at 1.67 GeV. We present the first measurements of the $e^+ e^-\to K_S^0 K_L^0 \pi^+\pi^-$, $K_S^0 K_S^0 \pi^+\pi^-$, and $K_S^0 K_S^0 K^+K^-$ cross sections, and study the intermediate resonance structures. We obtain the first observations of \jpsi decay to the $K_S^0 K_L^0 \pi^+\pi^-$, $K_S^0 K_S^0 \pi^+\pi^-$, and $K_S^0 K_S^0 K^+K^-$ final states.

We study the rare B meson decays B{+-,0} --> J/\psi\ K^+ K^- K{+-,0}, B{+-,0} --> J/\psi\ \phi\ K{+-,0}, and search for B0 --> J/\psi\ \phi, using 469 million BBbar events collected at the Upsilon(4S) resonance with the BABAR detector at the PEP-II e+e- asymmetric-energy collider. We present new measurements of branching fractions and a study of the J/\psi\phi mass distribution in search of new charmonium-like states. In addition, we search for the decay B0 --> J/\psi\ \phi, and find no evidence of a signal.

In the last years, high-resolution time tagging has emerged as the tool to tackle the problem of high-track density in the detectors of the next generation of experiments at particle colliders. Time resolutions below 50ps and event average repetition rates of tens of MHz on sensor pixels having a pitch of 50$\mu$m are typical minimum requirements. This poses an important scientific and technological challenge on the development of particle sensors and processing electronics. The TIMESPOT initiative (which stands for TIME and SPace real-time Operating Tracker) aims at the development of a full prototype detection system suitable for the particle trackers of the next-to-come particle physics experiments. This paper describes the results obtained on the first batch of TIMESPOT silicon sensors, based on a novel 3D MEMS (micro electro-mechanical systems) design. Following this approach, the performance of other ongoing silicon sensor developments has been matched and overcome, while using a technology which is known to be robust against radiation degradation. A time resolution of the order of 20ps has been measured at room temperature suggesting also possible improvements after further optimisations of the front-end electronics processing stage.

The DC-coupled Resistive Silicon Detectors (DC-RSD) are the evolution of the AC-coupled RSD (RSD) design, both based on the Low-Gain Avalanche Diode (LGAD) technology. The DC-RSD design concept intends to address a few known issues present in RSDs (e.g., baseline fluctuation, long tail-bipolar signals) while maintaining their advantages (e.g., signal spreading, 100% fill factor). The simulation of DC-RSD presents several unique challenges linked to the complex nature of its design and the large pixel size. The defining feature of DC-RSD, charge sharing over distances that can be as large as a millimetre, represents a formidable challenge for Technology-CAD (TCAD), the standard simulation tool. To circumvent this problem, we have developed a mixed-mode approach to the DC-RSD simulation, which exploits a combination of two simulation tools: TCAD and Spice. Thanks to this hybrid approach, it has been possible to demonstrate that, according to the simulation, the key features of the RSD, excellent timing and spatial resolutions (few tens of picoseconds and few microns), are maintained in the DC-RSD design. In this work, we present the developed models and methodology, mainly showing the results of device-level numerical simulation, which have been obtained with the state-of-the-art Synopsys Sentaurus TCAD suite of tools. Such results will provide all the necessary information for the first batch of DC-RSD produced by Fondazione Bruno Kessler (FBK) foundry in Trento, Italy.

Fermilab experiment E835 has measured the cross section for the reaction p̄p→e+e− at s=11.63, 12.43, 14.40 and 18.22 GeV2. From the analysis of the 66 observed events new high-precision measurements of the proton magnetic form factor are obtained.

We report evidence for the hc state of charmonium in its ηcγ decay mode and lack of evidence in the J/ψπ0 mode. We studied these channels in p¯p annihilations near the center of gravity of the PJ3 states, where the hc was reported in the J/ψπ0 mode by E760, our previous experiment, at 3526.2±0.15±0.2 MeV, with ΓR≤1 MeV. We observe an event excess in the ηcγ mode near 3526 MeV. Testing the null hypothesis of a linearly varying background cross section against the alternate hypothesis that includes a resonance near 3526 MeV, we reject the null hypothesis with P∼0.001. The resonance mass is 3525.8±0.2±0.2 MeV and the resonance width ≤1 MeV. We estimate 10.0±3.5<Γp¯pBηcγ<12.0±4.5 eV, corresponding to fixed values 0.5<ΓR<1.0 MeV. We find no event excess within the search region in the J/ψπ0 mode.4 MoreReceived 13 May 2005DOI:https://doi.org/10.1103/PhysRevD.72.032001©2005 American Physical Society

The first double diffractive cross-section measurement in the very forward region has been carried out by the TOTEM experiment at the LHC with center-of-mass energy of sqrt(s)=7 TeV. By utilizing the very forward TOTEM tracking detectors T1 and T2, which extend up to |eta|=6.5, a clean sample of double diffractive pp events was extracted. From these events, we measured the cross-section sigma_DD =(116 +- 25) mub for events where both diffractive systems have 4.7 <|eta|_min < 6.5 .

Based on a sample of 500 million ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}c\overline{c}$ events recorded by the BABAR detector at c.m. energies of close to 10.6 GeV, we report on a study of the decay ${D}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{e}^{+}{\ensuremath{\nu}}_{e}$. We measure the ratio of branching fractions, ${R}_{D}=\mathcal{B}({D}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{e}^{+}{\ensuremath{\nu}}_{e})/\mathcal{B}({D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+})=0.0713\ifmmode\pm\else\textpm\fi{}0.001{7}_{\text{stat}}\ifmmode\pm\else\textpm\fi{}0.002{4}_{\text{syst}}$, and use the present world average for $\mathcal{B}({D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+})$ to obtain $\mathcal{B}({D}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{e}^{+}{\ensuremath{\nu}}_{e})=(2.770\ifmmode\pm\else\textpm\fi{}0.06{8}_{\text{stat}}\ifmmode\pm\else\textpm\fi{}0.09{2}_{\text{syst}}\ifmmode\pm\else\textpm\fi{}0.03{7}_{\text{ext}})\ifmmode\times\else\texttimes\fi{}1{0}^{\ensuremath{-}3}$ where the third error accounts for the uncertainty on the branching fraction for the reference channel. The measured dependence of the differential branching fraction on ${q}^{2}$, the four-momentum transfer squared between the $D$ and the $\ensuremath{\pi}$ meson, is compared to various theoretical predictions for the hadronic form factor, ${f}_{+,D}^{\ensuremath{\pi}}({q}^{2})$, and the normalization $|{V}_{cd}|\ifmmode\times\else\texttimes\fi{}{f}_{+,D}^{\ensuremath{\pi}}({q}^{2}=0)=0.1374\ifmmode\pm\else\textpm\fi{}\phantom{\rule{0ex}{0ex}}0.003{8}_{\text{stat}}\ifmmode\pm\else\textpm\fi{}0.002{2}_{\text{syst}}\ifmmode\pm\else\textpm\fi{}0.000{9}_{\text{ext}}$. is extracted from a fit to data. Using the most recent LQCD prediction of ${f}_{+,D}^{\ensuremath{\pi}}({q}^{2}=0)=0.666\ifmmode\pm\else\textpm\fi{}0.029$, we obtain $|{V}_{cd}|=0.206\ifmmode\pm\else\textpm\fi{}0.00{7}_{\text{exp}}\ifmmode\pm\else\textpm\fi{}0.00{9}_{\mathrm{LQCD}}$. Assuming, instead, $|{V}_{cd}|=|{V}_{us}|=0.2252\ifmmode\pm\else\textpm\fi{}0.0009$, we obtain ${f}_{+,D}^{\ensuremath{\pi}}({q}^{2}=0)=0.610\ifmmode\pm\else\textpm\fi{}0.02{0}_{\text{exp}}\ifmmode\pm\else\textpm\fi{}0.00{5}_{\text{ext}}$. The ${q}^{2}$ dependence of ${f}_{+,D}^{\ensuremath{\pi}}({q}^{2})$ is compared to a variety of multipole parametrizations. This information is applied to ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{e}^{+}{\ensuremath{\nu}}_{e}$ decays and, combined with an earlier ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{e}^{+}{\ensuremath{\nu}}_{e}$ measurement by BABAR, is used to derive estimates of $|{V}_{ub}|$.

The TIMESPOT project aims at the construction of a mini-tracker demonstrator implementing both high space and time resolutions at the single pixel level. The pixels have a pitch of 55 × 55 μm2. Specified time resolution is equal or better than 50 ps. Developed sensors are based both on 3D silicon and diamond technologies, whose layout and fabrication process have been suitably optimized for best time resolution. Read-out pixel electronics is being developed in 28-nm CMOS technology. The first batch of 3D silicon sensors, containing several test structures based on different geometries of the electrodes, has been delivered in June 2019 and has been tested against its timing performance both under laser and minimum ionizing particle beams. In the present paper, the output of these starting measurements is presented. The sensors show very good timing performance, having σ¡30 ps (sigma), although operated with non-optimized front-end electronics and in noisy environment. These results represent an important step forward in the development of pixels with timing operating at extremely high interaction rates and fluences, as required in the next generation of upgraded colliders.

The TOTEM experiment has measured the charged-particle pseudorapidity density dNch/dη in pp collisions at for 5.3<|η|<6.4 in events with at least one charged particle with transverse momentum above 40 MeV/c in this pseudorapidity range. This extends the analogous measurement performed by the other LHC experiments to the previously unexplored forward η region. The measurement refers to more than 99% of non-diffractive processes and to single and double diffractive processes with diffractive masses above ∼3.4 GeV/c2, corresponding to about 95% of the total inelastic cross-section. The dNch/dη has been found to decrease with |η|, from 3.84 ± 0.01(stat) ± 0.37(syst) at |η|=5.375 to 2.38±0.01(stat)±0.21(syst) at |η|=6.375. Several MC generators have been compared to data; none of them has been found to fully describe the measurement.

We present Dalitz plot analyses for the decays of $B$ mesons to ${D}^{\ensuremath{-}}{D}^{0}{K}^{+}$ and ${\overline{D}}^{0}{D}^{0}{K}^{+}$. We report the observation of the ${D}_{s1}^{*}(2700{)}^{+}$ resonance in these two channels and obtain measurements of the mass $M({D}_{s1}^{*}(2700{)}^{+})={2699}_{\ensuremath{-}7}^{+14}\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ and of the width $\mathrm{\ensuremath{\Gamma}}({D}_{s1}^{*}(2700{)}^{+})={127}_{\ensuremath{-}19}^{+24}\text{ }\text{ }\mathrm{MeV}$, including statistical and systematic uncertainties. In addition, we observe an enhancement in the ${D}^{0}{K}^{+}$ invariant mass around $2350--2500\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ in both decays ${B}^{0}\ensuremath{\rightarrow}{D}^{\ensuremath{-}}{D}^{0}{K}^{+}$ and ${B}^{+}\ensuremath{\rightarrow}{\overline{D}}^{0}{D}^{0}{K}^{+}$, which we are not able to interpret. The results are based on $429\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of data containing $471\ifmmode\times\else\texttimes\fi{}1{0}^{6}B\overline{B}$ pairs collected at the $\mathrm{\ensuremath{\Upsilon}}(4S)$ resonance with the BABAR detector at the SLAC National Accelerator Laboratory.

We present a search for a neutral, long-lived particle L that is produced in e+ e- collisions and decays at a significant distance from the e+ e- interaction point into various flavor combinations of two oppositely charged tracks. The analysis uses an e+ e- data sample with a luminosity of 489.1 fb(-1) collected by the BABAR detector at the ϒ(4S), ϒ(3S), and ϒ(2S) resonances and just below the ϒ(4S). Fitting the two-track mass distribution in search of a signal peak, we do not observe a significant signal, and set 90% confidence level upper limits on the product of the L production cross section, branching fraction, and reconstruction efficiency for six possible two-body L decay modes as a function of the L mass. The efficiency is given for each final state as a function of the mass, lifetime, and transverse momentum of the candidate, allowing application of the upper limits to any production model. In addition, upper limits are provided on the branching fraction B(B→XsL), where Xs is a strange hadronic system.

We report on a search for eleven lepton-number violating processes B+ -> X- l+ l'+ with X- = K-, pi-, rho-, K*- or D- and l+/l'+ = e+ or mu+, using a sample of 471+/-3 million BBbar events collected with the BaBar detector at the PEP-II e+e- collider at the SLAC National Accelerator Laboratory. We find no evidence for any of these modes and place 90% confidence level upper limits on their branching fractions in the range $(1.5-26)\times 10^{-7}$.

We present results of a search for $CP$ violation in ${B}^{0}\mathrm{\text{\ensuremath{-}}}\text{ }{\overline{B}}^{0}$ mixing with the BABAR detector. We select a sample of ${B}^{0}\ensuremath{\rightarrow}{D}^{*\ensuremath{-}}X{\ensuremath{\ell}}^{+}\ensuremath{\nu}$ decays with a partial reconstruction method and use kaon tagging to assess the flavor of the other $B$ meson in the event. We determine the $CP$ violating asymmetry ${\mathcal{A}}_{CP}\ensuremath{\equiv}[N({B}^{0}{B}^{0})\ensuremath{-}N({\overline{B}}^{0}{\overline{B}}^{0})]/[N({B}^{0}{B}^{0})+N({\overline{B}}^{0}{\overline{B}}^{0})]=(0.06\ifmmode\pm\else\textpm\fi{}{0.17}_{\ensuremath{-}0.32}^{+0.38})%$, corresponding to ${\ensuremath{\Delta}}_{CP}=1\ensuremath{-}|q/p|=(0.29\ifmmode\pm\else\textpm\fi{}{0.84}_{\ensuremath{-}1.61}^{+1.88})\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$.

We study the processes $\ensuremath{\gamma}\ensuremath{\gamma}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}\ensuremath{\eta}$ and $\ensuremath{\gamma}\ensuremath{\gamma}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$ using a data sample of $519\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ recorded with the BABAR detector operating at the SLAC PEP-II asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider at center-of-mass energies at and near the $\mathit{\ensuremath{\Upsilon}}(nS)$ ($n=2,3,4$) resonances. We observe ${\ensuremath{\eta}}_{c}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$ and ${\ensuremath{\eta}}_{c}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}\ensuremath{\eta}$ decays, measure their relative branching fraction, and perform a Dalitz plot analysis for each decay. We observe the ${K}_{0}^{*}(1430)\ensuremath{\rightarrow}K\ensuremath{\eta}$ decay and measure its branching fraction relative to the $K\ensuremath{\pi}$ decay mode to be $\mathcal{R}({K}_{0}^{*}(1430))=\frac{\mathcal{B}({K}_{0}^{*}(1430)\ensuremath{\rightarrow}K\ensuremath{\eta})}{\mathcal{B}({K}_{0}^{*}(1430)\ensuremath{\rightarrow}K\ensuremath{\pi})}=0.092\ifmmode\pm\else\textpm\fi{}0.02{5}_{\ensuremath{-}0.025}^{+0.010}$. The ${\ensuremath{\eta}}_{c}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}\ensuremath{\eta}$ and ${K}_{0}^{*}(1430)\ensuremath{\rightarrow}K\ensuremath{\eta}$ results correspond to the first observations of these channels. The data also show evidence for ${\ensuremath{\eta}}_{c}(2S)\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$ and first evidence for ${\ensuremath{\eta}}_{c}(2S)\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}\ensuremath{\eta}$.

We report on a study of the angular distributions in the radiative decay of the χc1 and χc2 states formed in p¯p annihilations. These distributions depend on the dynamics of the formation process and the multipole structure of the radiative decay. Using 2090 χc1 and 5908 χc2 events, we have measured the fractional magnetic quadrupole amplitude to be a2(χc1)≃M2/E1=0.002±0.032, and a2(χc2)=−0.093−0.041+0.039. We have also measured the square of the helicity 0 fractional amplitude in the χc2 formation process to be B02=0.13±0.08. Received 3 July 2001DOI:https://doi.org/10.1103/PhysRevD.65.052002©2002 American Physical Society

Proton-proton elastic scattering has been measured by the TOTEM experiment at the CERN Large Hadron Collider at √s = 7 TeV in special runs with the Roman Pot detectors placed as close to the outgoing beam as seven times the transverse beam size. The differential cross-section measurements are reported in the |t|-range of 0.36 to 2.5 GeV2. Extending the range of data to low t values from 0.02 to 0.33 GeV2, and utilizing the luminosity measurements of CMS, the total proton-proton cross section at √s = 7 TeV is measured to be (98.3 ±0.2stat ±2.8syst) mb.

The TOTEM Experiment is designed to measure the total proton-proton cross-section with the luminosity-independent method and to study elastic and diffractive pp scattering at the LHC. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the interaction point IP5, two tracking telescopes, T1 and T2, are installed on each side of the IP in the pseudorapidity region 3.1 < = |eta | < = 6.5, and special movable beam-pipe insertions - called Roman Pots (RP) - are placed at distances of +- 147 m and +- 220 m from IP5. This article describes in detail the working of the TOTEM detector to produce physics results in the first three years of operation and data taking at the LHC.

This paper describes the design and the performance of the timing detector developed by the TOTEM Collaboration for the Roman Pots (RPs) to measure the Time-Of-Flight (TOF) of the protons produced in central diffractive interactions at the LHC . The measurement of the TOF of the protons allows the determination of the longitudinal position of the proton interaction vertex and its association with one of the vertices reconstructed by the CMS detectors. The TOF detector is based on single crystal Chemical Vapor Deposition (scCVD) diamond plates and is designed to measure the protons TOF with about 50 ps time precision. This upgrade to the TOTEM apparatus will be used in the LHC run 2 and will tag the central diffractive events up to an interaction pileup of about 1. A dedicated fast and low noise electronics for the signal amplification has been developed. The digitization of the diamond signal is performed by sampling the waveform. After introducing the physics studies that will most profit from the addition of these new detectors, we discuss in detail the optimization and the performance of the first TOF detector installed in the LHC in November 2015.

We measure the direct CP violation asymmetry, A_CP, in B to X_s gamma and the isospin difference of the asymmetry, Delta A_CP, using 429 fb^-1 of data collected at Upsilon(4S) resonance with the BaBar detector at the PEP-II asymmetric-energy e+e- storage rings operating at the SLAC National Accelerator Laboratory. B mesons are reconstructed from 10 charged B final states and 6 neutral B final states. We find A_CP = +(1.7 +- 1.9 +- 1.0)%, which is in agreement with the Standard Model prediction and provides an improvement on the world average. Moreover, we report the first measurement of the difference between A_CP for charged and neutral decay modes, Delta A_CP = +(5.0 +- 3.9 +- 1.5)%. Using the value of Delta A_CP, we also provide 68% and 90% confidence intervals on the imaginary part of the ratio of the Wilson coefficients corresponding to the chromo-magnetic dipole and the electromagnetic dipole transitions.

The pseudorapidity density of charged particles dN $$_{ ch }$$ /d $$\eta $$ is measured by the TOTEM experiment in proton–proton collisions at $$\sqrt{s} = 8$$ TeV within the range $$3.9<\eta <4.7$$ and $$-6.95<\eta <-6.9$$ . Data were collected in a low intensity LHC run with collisions occurring at a distance of 11.25 m from the nominal interaction point. The data sample is expected to include 96–97 % of the inelastic proton–proton interactions. The measurement reported here considers charged particles with $$p_T>0$$ MeV/c, produced in inelastic interactions with at least one charged particle in $$-7<\eta <-6$$ or $$3.7<\eta <4.8$$ . The dN $$_{ ch }$$ /d $$\eta $$ has been found to decrease with $$|\eta |$$ , from 5.11 $$\pm $$ 0.73 at $$\eta =3.95$$ to 1.81 $$\pm $$ 0.56 at $$\eta =-$$ 6.925. Several Monte Carlo generators are compared to the data and are found to be within the systematic uncertainty of the measurement.

We present a measurement of the asymmetry A_{CP} between same-sign inclusive dilepton samples ℓ^{+}ℓ^{+} and ℓ^{-}ℓ^{-} (ℓ=e, μ) from semileptonic B decays in ϒ(4S)→BB[over ¯] events, using the complete data set recorded by the BABAR experiment near the ϒ(4S) resonance, corresponding to 471×10^{6} BB[over ¯] pairs. The asymmetry A_{CP} allows comparison between the mixing probabilities P(B[over ¯]^{0}→B^{0}) and P(B^{0}→B[over ¯]^{0}), and therefore probes CP and T violation. The result, A_{CP}=[-3.9±3.5(stat)±1.9(syst)]×10^{-3}, is consistent with the standard model expectation.

The resonance parameters of the χc0, the 13P0 state of charmonium, have been measured at the Fermilab Antiproton Accumulator in the reaction p̄p→χc0→γJ/ψ→γ(e+e−). A large data sample collected during the year 2000 run yields the results: M(χc0)=3415.4±0.4±0.2 MeV/c2, Γ(χc0)=9.8±1.0±0.1 MeV, B(χc0→p̄p)×B(χc0→γJ/ψ)×B(J/ψ→(e+e−))=(1.61±0.11±0.08)×10−7. Taking B(χc0→γJ/ψ) and B(J/ψ→e+e−) from the literature, we obtain B(χc0→p̄p)=(4.1±0.3+1.6−0.9)×10−4 and Γ(χc0→p̄p)=(4.0±0.4+1.6−0.9) keV.

We measure the mass difference, $\ensuremath{\Delta}{m}_{0}$, between the ${D}^{*}(2010{)}^{+}$ and the ${D}^{0}$ and the natural linewidth, $\ensuremath{\Gamma}$, of the transition ${D}^{*}(2010{)}^{+}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{+}$. The data were recorded with the BABAR detector at center-of-mass energies at and near the $\ensuremath{\Upsilon}(4S)$ resonance, and correspond to an integrated luminosity of approximately $477\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. The ${D}^{0}$ is reconstructed in the decay modes ${D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ and ${D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$. For the decay mode ${D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ we obtain $\ensuremath{\Gamma}=(83.4\ifmmode\pm\else\textpm\fi{}1.7\ifmmode\pm\else\textpm\fi{}1.5)\text{ }\text{ }\mathrm{keV}$ and $\ensuremath{\Delta}{m}_{0}=(145425.6\ifmmode\pm\else\textpm\fi{}0.6\ifmmode\pm\else\textpm\fi{}1.8)\text{ }\text{ }\mathrm{keV}$, where the quoted errors are statistical and systematic, respectively. For the ${D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ mode we obtain $\ensuremath{\Gamma}=(83.2\ifmmode\pm\else\textpm\fi{}1.5\ifmmode\pm\else\textpm\fi{}2.6)\text{ }\text{ }\mathrm{keV}$ and $\ensuremath{\Delta}{m}_{0}=(145426.6\ifmmode\pm\else\textpm\fi{}0.5\ifmmode\pm\else\textpm\fi{}2.0)\text{ }\text{ }\mathrm{keV}$. The combined measurements yield $\ensuremath{\Gamma}=(83.3\ifmmode\pm\else\textpm\fi{}1.2\ifmmode\pm\else\textpm\fi{}1.4)\text{ }\text{ }\mathrm{keV}$ and $\ensuremath{\Delta}{m}_{0}=(145425.9\ifmmode\pm\else\textpm\fi{}0.4\ifmmode\pm\else\textpm\fi{}1.7)\text{ }\text{ }\mathrm{keV}$; the width is a factor of approximately 12 times more precise than the previous value, while the mass difference is a factor of approximately 6 times more precise.

We search for the decay $\mathit{\ensuremath{\Upsilon}}(1S)\ensuremath{\rightarrow}\ensuremath{\gamma}{A}^{0}$, ${A}^{0}\ensuremath{\rightarrow}gg$ or $\mathrm{s}\overline{\mathrm{s}}$, where ${A}^{0}$ is the pseudoscalar light Higgs boson predicted by the next-to-minimal supersymmetric Standard Model. We use a sample of $(17.6\ifmmode\pm\else\textpm\fi{}0.3)\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $\mathit{\ensuremath{\Upsilon}}(1S)$ mesons produced in the BABAR experiment via ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\mathit{\ensuremath{\Upsilon}}(2S)\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\mathit{\ensuremath{\Upsilon}}(1S)$. We see no significant signal and set 90%-confidence-level upper limits on the product branching fraction $\mathcal{B}(\mathit{\ensuremath{\Upsilon}}(1S)\ensuremath{\rightarrow}\ensuremath{\gamma}{A}^{0})\ifmmode\cdot\else\textperiodcentered\fi{}\mathcal{B}({A}^{0}\ensuremath{\rightarrow}gg\text{ }\mathrm{\text{or}}\text{ }\mathrm{s}\overline{\mathrm{s}})$ ranging from ${10}^{\ensuremath{-}6}$ to ${10}^{\ensuremath{-}2}$ for ${A}^{0}$ masses in the range $0.5--9.0\text{ }\text{ }\mathrm{GeV}/{c}^{2}$.

Precise knowledge of the beam optics at the LHC is crucial to fulfil the physics goals of the TOTEM experiment, where the kinematics of the scattered protons is reconstructed with the near-beam telescopes -- so-called Roman Pots (RP). Before being detected, the protons' trajectories are influenced by the magnetic fields of the accelerator lattice. Thus precise understanding of the proton transport is of key importance for the experiment. A novel method of optics evaluation is proposed which exploits kinematical distributions of elastically scattered protons observed in the RPs. Theoretical predictions, as well as Monte Carlo studies, show that the residual uncertainty of this optics estimation method is smaller than 0.25 percent.

Abstract The TOTEM collaboration at the CERN LHC has measured the differential cross-section of elastic proton–proton scattering at $$\sqrt{s} = 8\,\mathrm{TeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> <mml:mo>=</mml:mo> <mml:mn>8</mml:mn> <mml:mspace /> <mml:mi>TeV</mml:mi> </mml:mrow> </mml:math> in the squared four-momentum transfer range $$0.2\,\mathrm{GeV^{2}}&lt; |t| &lt; 1.9\,\mathrm{GeV^{2}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>0.2</mml:mn> <mml:mspace /> <mml:msup> <mml:mi>GeV</mml:mi> <mml:mn>2</mml:mn> </mml:msup> <mml:mo>&lt;</mml:mo> <mml:mrow> <mml:mo>|</mml:mo> <mml:mi>t</mml:mi> <mml:mo>|</mml:mo> </mml:mrow> <mml:mo>&lt;</mml:mo> <mml:mn>1.9</mml:mn> <mml:mspace /> <mml:msup> <mml:mi>GeV</mml:mi> <mml:mn>2</mml:mn> </mml:msup> </mml:mrow> </mml:math> . This interval includes the structure with a diffractive minimum (“dip”) and a secondary maximum (“bump”) that has also been observed at all other LHC energies, where measurements were made. A detailed characterisation of this structure for $$\sqrt{s} = 8\,\mathrm{TeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> <mml:mo>=</mml:mo> <mml:mn>8</mml:mn> <mml:mspace /> <mml:mi>TeV</mml:mi> </mml:mrow> </mml:math> yields the positions, $$|t|_{\mathrm{dip}} = (0.521 \pm 0.007)\,\mathrm{GeV^2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mo>|</mml:mo> <mml:mi>t</mml:mi> <mml:mo>|</mml:mo> </mml:mrow> <mml:mi>dip</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mrow> <mml:mo>(</mml:mo> <mml:mn>0.521</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.007</mml:mn> <mml:mo>)</mml:mo> </mml:mrow> <mml:mspace /> <mml:msup> <mml:mi>GeV</mml:mi> <mml:mn>2</mml:mn> </mml:msup> </mml:mrow> </mml:math> and $$|t|_{\mathrm{bump}} = (0.695 \pm 0.026)\,\mathrm{GeV^2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mo>|</mml:mo> <mml:mi>t</mml:mi> <mml:mo>|</mml:mo> </mml:mrow> <mml:mi>bump</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mrow> <mml:mo>(</mml:mo> <mml:mn>0.695</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.026</mml:mn> <mml:mo>)</mml:mo> </mml:mrow> <mml:mspace /> <mml:msup> <mml:mi>GeV</mml:mi> <mml:mn>2</mml:mn> </mml:msup> </mml:mrow> </mml:math> , as well as the cross-section values, $$\left. {\mathrm{d}\sigma /\mathrm{d}t}\right| _{\mathrm{dip}} = (15.1 \pm 2.5)\,\mathrm{{\mu b/GeV^2}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mfenced> <mml:mrow> <mml:mi>d</mml:mi> <mml:mi>σ</mml:mi> <mml:mo>/</mml:mo> <mml:mi>d</mml:mi> <mml:mi>t</mml:mi> </mml:mrow> </mml:mfenced> <mml:mi>dip</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mrow> <mml:mo>(</mml:mo> <mml:mn>15.1</mml:mn> <mml:mo>±</mml:mo> <mml:mn>2.5</mml:mn> <mml:mo>)</mml:mo> </mml:mrow> <mml:mspace /> <mml:mrow> <mml:mi>μ</mml:mi> <mml:mi>b</mml:mi> <mml:mo>/</mml:mo> <mml:msup> <mml:mi>GeV</mml:mi> <mml:mn>2</mml:mn> </mml:msup> </mml:mrow> </mml:mrow> </mml:math> and $$\left. {\mathrm{d}\sigma /\mathrm{d}t}\right| _{\mathrm{bump}} = (29.7 \pm 1.8)\,\mathrm{{\mu b/GeV^2}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mfenced> <mml:mrow> <mml:mi>d</mml:mi> <mml:mi>σ</mml:mi> <mml:mo>/</mml:mo> <mml:mi>d</mml:mi> <mml:mi>t</mml:mi> </mml:mrow> </mml:mfenced> <mml:mi>bump</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mrow> <mml:mo>(</mml:mo> <mml:mn>29.7</mml:mn> <mml:mo>±</mml:mo> <mml:mn>1.8</mml:mn> <mml:mo>)</mml:mo> </mml:mrow> <mml:mspace /> <mml:mrow> <mml:mi>μ</mml:mi> <mml:mi>b</mml:mi> <mml:mo>/</mml:mo> <mml:msup> <mml:mi>GeV</mml:mi> <mml:mn>2</mml:mn> </mml:msup> </mml:mrow> </mml:mrow> </mml:math> , for the dip and the bump, respectively.

We report the branching ratios of the ${\ensuremath{\chi}}_{c2}{(1}^{3}{P}_{2})$ and ${\ensuremath{\chi}}_{c0}{(1}^{3}{P}_{0})$ charmonium resonances to two photons using event samples collected by Fermilab experiment E835 in the reactions $\overline{p}\stackrel{\ensuremath{\rightarrow}}{p}{\ensuremath{\chi}}_{c2}{(1}^{3}{P}_{2})[{\ensuremath{\chi}}_{c0}{(1}^{3}{P}_{0})].$ Our result for the ${\ensuremath{\chi}}_{c2}$ is $B({\ensuremath{\chi}}_{c2}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma})=(1.35\ifmmode\pm\else\textpm\fi{}0.25\ifmmode\pm\else\textpm\fi{}0.12)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}.$ We set a 95% upper limit for the ${\ensuremath{\chi}}_{c0}$ branching ratio $B({\ensuremath{\chi}}_{c0}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma})$ at $2.09\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}.$

We provide a comprehensive description of experiment E835 at Fermilab, a high-precision experimental study of charmonium bound states. The c̄c states are formed in p̄p annihilations of cooled antiprotons stored in the Fermilab Antiproton Accumulator using a dense internal hydrogen gas-jet target. We describe the experimental strategies adopted for detecting the tiny c̄c resonant signals in the huge non-resonant hadronic background, and for measuring resonance parameters with high precision.

Abstract The TOTEM experiment, small in size compared to the others at the LHC, is dedicated to the measurement of the total proton–proton cross-sections with a luminosity-independent method and to the study of elastic and diffractive scattering at the LHC. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the IP5 interaction point, two tracking telescopes, T1 and T2, will be installed on each side in the pseudo-rapidity region between 3.1 and 6.5, and Roman Pot stations will be placed at distances of 147 and 220 m from IP5. The telescope closest to the interaction point (T1, centred at z=9 m) consists of Cathode Strip Chambers (CSC), while the second one (T2, centred at 13.5 m), makes use of Gas Electron Multipliers (GEM). The proton detectors in the Roman Pots are silicon devices designed by TOTEM with the specific objective of reducing down to a few tens of microns the insensitive area at the edge. High efficiency as close as possible to the physical detector boundary is an essential feature. It maximizes the experimental acceptance for protons scattered elastically or interactively at polar angles down to a few micro-radians at IP5. To measure protons at the lowest possible emission angles, special beam optics have been conceived to optimize proton detection in terms of acceptance and resolution. The read-out of all TOTEM subsystems is based on the custom-developed digital VFAT chip with trigger capability.

We present measurements of the inclusive production of antideuterons in $e^+e^-$ annihilation into hadrons at $\approx 10.58 \mathrm{\,Ge\kern -0.1em V}$ center-of-mass energy and in $\Upsilon(1S,2S,3S)$ decays. The results are obtained using data collected by the BABAR detector at the PEP-II electron-positron collider. Assuming a fireball spectral shape for the emitted antideuteron momentum, we find $\mathcal{B}(\Upsilon(1S) \to \bar{d}X) = (2.81 \pm 0.49 \mathrm{(stat)} {}^{+0.20}_{-0.24} \mathrm{(syst)})/! \times /! 10^{-5}$, $\mathcal{B}(\Upsilon(2S) \to \bar{d}X) = (2.64 \pm 0.11 \mathrm{(stat)} {}^{+0.26}_{-0.21} \mathrm{(syst)})/! \times /! 10^{-5}$, $\mathcal{B}(\Upsilon(3S) \to \bar{d}X) = (2.33 \pm 0.15 \mathrm{(stat)} {}^{+0.31}_{-0.28} \mathrm{(syst)})/! \times /! 10^{-5}$, and $\sigma (e^+e^- \to \bar{d}X) = (9.63 \pm 0.41 \mathrm{(stat)} {}^{+1.17}_{-1.01} \mathrm{(syst)}) \mbox{\,fb}$.

The BaBar experiment at PEPII relies on the instrumentation of the flux return (IFR) for both muon identification and KL detection. The active detector is composed of resistive plate chambers (RPCs) operated in streamer mode. Since the start of operation the RPCs have suffered persistent efficiency deterioration and dark current increase problems. The “autopsy” of bad BaBar RPCs revealed that in many cases uncured linseed oil droplets had formed on the inner surface of the Bakelite plates, leading to current paths from oil “stalagmites” bridging the 2 mm gap. In this paper, a possible model of this “stalagmite” formation and its effect on the dark current and efficiency of RPC chambers is presented. Laboratory test results strongly support this model. Based upon this model we are searching for solutions to eliminate the unfavorable effect of the oil stalagmites. The lab tests show that the stalagmite resistivity increases dramatically if exposed to the air, an observation that points to a possible way to remedy the damage and increase the efficiency. We have seen that flowing an oxygen gas mixture into the chamber helps to polymerize the uncured linseed oil. Consequently, the resistivity of the bridged oil stalagmites increases, as does that of the oil coating on the frame edges and spacers, significantly reducing the RPC dark currents and low-efficiency regions. We have tested this idea on two chambers removed from BaBar because of their low efficiency and high dark current. These test results are reported in the paper, and two other remediation methods also mentioned. We continue to study this problem, and try to find new treatments with permanent improvement.

The JETSET (PS202) experiment at CERN-LEAR searches for hadronic resonances by means of in-flight antiproton-proton annihilations in the reaction pp → φφ. In order to obtain sufficient luminosity and good final-state mass resolution, this experiment uses an internal hydrogen-cluster jet target intersecting the LEAR antiproton beam. We report on the study of the reaction pp → 4K± at 1.4 GeV / c incident p̄ momentum, and we present the first experimental observation of a stro φφ signal in this reaction.

The BABAR detector has operated nearly 200 Resistive Plate Chambers (RPCs), constructed as part of an upgrade of the forward endcap muon detector, for the past two years.The RPCs experience widely different background and luminosity-driven singles rates (0.01-10 Hz/cm 2 ) depending on position within the endcap.Some regions have integrated over 0.3 C/cm 2 .RPC efficiency measured with cosmic rays is high and stable.The average efficiency measured with beam is also high.However, a few of the highest rate RPCs have suffered efficiency losses of 5-15%.Although constructed with improved techniques and minimal use of linseed oil, many of the RPCs, which are operated in streamer mode, have shown increased dark currents and noise rates that are correlated with the direction of the gas flow and the integrated current.Studies of the above aging effects are presented and correlated with detector operating conditions.

We present new precision measurements of the ψ(2S) total and partial widths from excitation curves obtained in antiproton–proton annihilations by Fermilab experiment E835 at the Antiproton Accumulator in the year 2000. A new technique of complementary scans was developed to study narrow resonances with stochastically cooled antiproton beams. The technique relies on precise revolution-frequency and orbit-length measurements, while making the analysis of the excitation curve almost independent of machine lattice parameters. We study the ψ(2S) meson through the processes p¯p→e+e− and p¯p→J/ψ+X→e+e−+X. We measure the width to be Γ=290±25(sta)±4(sys)keV and the combination of partial widths Γe+e−Γp¯p/Γ=579±38(sta)±36(sys)meV, which represent the most precise measurements to date.

Received 7 October 2013DOI:https://doi.org/10.1103/PhysRevD.88.079902© 2013 American Physical Society

We present the results of a search for the rare flavor-changing neutral-current decays B --> pi l+l- (pi=pi+/-, pi0 and l = e,mu) and B0 --> eta l+l- using a sample of e+e- --> Y(4S) BB decays decays corresponding to 428 fb^-1 of integrated luminosity collected by the BABAR detector. No significant signal is observed, and we set an upper limit on the isospin and lepton-flavor averaged branching fraction of BF(B --> pi l+l-) < 7.0 x 10^-8 and a lepton-flavor averaged upper limit of BF(B0 --> eta l+l-) < 9.2 x 10^-8, both at the 90% confidence level. We also report 90% confidence level branching fraction upper limits for the individual modes B+ --> pi+ e+e-, B0 --> pi0 e+e-, B+ --> pi+ mu+mu-, B0 --> pi0 mu+mu-, B0 --> eta e+e-, and B0 --> eta mu+mu-.

Received 16 December 2014DOI:https://doi.org/10.1103/PhysRevD.91.019901© 2015 American Physical Society

The hydrogen Jet Target for Experiment 835 (Charmonium spectroscopy) at the Fermilab Antiproton Accumulator can provide a variable density cluster stream up to 3.2×1014 atoms/cm3 in order to allow an instantaneous luminosity greater than 2×1031 cm−2 s−1. This result can be achieved due to the helium refrigerated expansion stage which provides the cluster stream and due to the pumping and the alignment system which significantly lower the background gas. Details on the construction and the performances, measured in the laboratory and during the run, are discussed.

The resonance parameters of the charmonium ground state, ηc(11S0), have been measured by means of the reaction p̄p→ηc→γγ. The mass and total width are determined to be 2984.1±2.1±1.0 MeV/c2 and 20.4+7.7−6.7±2.0 MeV, respectively. The product of branching ratios B(p̄p→ηc)B(ηc→γγ) is determined to be 22.4+3.8−3.7±2.0×10−8, from which B(ηc→γγ)=1.87+0.32+0.95−0.31−0.50×10−4, and Γ(ηc→γγ)=3.8+1.1+1.9−1.0−1.0 keV are derived using B(ηc→p̄p)=(12±4)×10−4 from the literature.

We have studied the 3PJ (χc) states of charmonium in formation by antiproton–proton annihilations in experiment E835 at the Fermilab Antiproton Source. We report new measurements of the mass, width, and B(χcJ→p¯p)Γ(χcJ→J/ψ+anything) for the χc1 and χc2 by means of the inclusive reaction p¯p→χcJ→J/ψ+anything→(e+e−)+anything. Using the subsample of events where χcJ→γ+J/ψ→γ+(e+e−) is fully reconstructed, we derive B(χcJ→p¯p)Γ(χcJ→J/ψ+γ). We summarize the results of the E760 (updated) and E835 measurements of mass, width and B(χcJ→p¯p)Γ(χcJ→J/ψ+γ) (J=0,1,2) and discuss the significance of these measurements.

We report a measurement of the ${D}^{0}$ meson mass using the decay chain ${D}^{*}(2010{)}^{+}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{+}$ with ${D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{K}^{\ensuremath{-}}{K}^{+}{\ensuremath{\pi}}^{+}$. The data were recorded with the BABAR detector at center-of-mass energies at and near the $\mathit{\ensuremath{\Upsilon}}(4S)$ resonance, and correspond to an integrated luminosity of approximately $477\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. We obtain $m({D}^{0})=(1864.841\ifmmode\pm\else\textpm\fi{}0.048\ifmmode\pm\else\textpm\fi{}0.063)\text{ }\text{ }\mathrm{MeV}$, where the quoted errors are statistical and systematic, respectively. The uncertainty of this measurement is half that of the best previous measurement.

We have observed exclusive decays of the ψ′ in an experiment where the ψ′ is formed in antiproton-proton annihilations. We report the branching ratios B(ψ′→e+e−)=(8.3±0.5stat±0.7syst)×10−3, B(ψ′→J/ψπ+π−)=0.283±0.021stat±0.020syst, B(ψ′→J/ψπ0π0)=0.184±0.019stat±0.013syst, B(ψ′→J/ψη)=0.032±0.010stat±0.002syst. Received 3 September 1996DOI:https://doi.org/10.1103/PhysRevD.55.1153©1997 American Physical Society

We report on a search by Fermilab experiment E835 for the η′c (21S0) charmonium resonance in the process ¯p→pη′c→γγ. No signal was observed and, based on 34 pb−1 integrated luminosity, we determine the following upper limits (90% confidence level) to the product of the branching ratios for a resonance mass in the region 3575–3660 MeV/c2: Br(η′c→¯pp)×Br(η′c→γγ)<12.0×10−8 for Γ=5 MeV; <5.9×10−8 for Γ=10 MeV; <4.8×10−8 for Γ=15 MeV. Combining the present data with those of the predecessor experiment, E760, the upper limits become 8.0×10−8, 5.0×10−8, and 4.5×10−8, respectively. In the restricted region 3589–3599 MeV/c2, where a candidate was reported by the Crystal Ball experiment, we obtain the following limits from the combined E760–E835 experiments: Br(η′c→¯pp)×Br(η′c→γγ)<5.6×10−8 for Γ=5 MeV; <3.7×10−8 for Γ=8 MeV. A comparison of these with other experimental results is presented.Received 18 January 2001DOI:https://doi.org/10.1103/PhysRevD.64.052003©2001 American Physical Society

We present the first measurement of the angular distribution for the exclusive process p¯p→ψ(2S)→e+e− based on a sample of 6844 events collected by the Fermilab E835 experiment. We find that the angular distribution is well described by the expected functional form dNdcosθ∗∝1+λcos2θ∗, where θ∗ is the angle between the antiproton and the electron in the center of mass frame, with λ=0.67±0.15(stat)±0.04(sys). The measured value for λ implies a small but non-zero ψ(2S) helicity 0 formation amplitude in p¯p, comparable to what is observed in J/ψ decays to baryon pairs.

The BaBar experiment uses a big system based on RPC detectors to discriminate muons from pions and to identify neutral hadrons. About 2000m2 of RPC chambers have been working at SLAC since the end of 1998. We report on the performances of the RPC chambers focusing on new problems discovered in the RPC behaviour. These problems started very soon after the installation of the chambers on the detector when the high-ambient temperature triggered an increase of dark currents inside the chambers and a reduction of the efficiency. Careful analysis of the BaBar data and dedicated R&D efforts in the laboratory have helped to identify the main source of the trouble in the linseed oil varnish on the bakelite electrodes.

The muon and neutral hadron detector (instrumented flux return or IFR) in the forward endcap of the BaBar detector at SLAC was upgraded by the installation of a new generation of resistive plate chambers (RPCs) and by increasing the absorber. The chamber replacement was made necessary by the rapid aging and efficiency loss of the original BaBar RPCs. Based on our experience with those original RPCs and 24 RPCs with thinner linseed oil treatments, improvements in the design, construction, and testing of the new generation RPCs were implemented and are described in detail.

Evidence is presented for the baryonic $B$ meson decay $\bar{B}\rightarrow D^0 \Lambda \bar{\Lambda}$ based on a data sample of $471 \times 10^6$ $B\bar{B}$ pairs collected with the {\it BABAR} detector at the PEP2 asymmetric $e^+e^-$ collider located at the SLAC National Accelerator Laboratory. The branching fraction is determined to be $\mathcal{B}(\bar{B}\rightarrow D^0 \Lambda \bar{\Lambda}) = (9.8^{+2.9}_{-2.6} \pm 1.9)\times 10^{-6}$, corresponding to a significance of $3.4$ standard deviations including systematic uncertainties. A search for the related baryonic $B$ meson decay $\bar{B}\rightarrow D^0 \Sigma^0 \bar{\Lambda}$ with $\Sigma^0\rightarrow\Lambda\gamma$ is performed and an upper limit $\mathcal{B}(\bar{B}\rightarrow D^0 \Sigma^0 \bar{\Lambda} + \bar{B}\rightarrow D^0 \Lambda \bar{\Sigma}^0) < 3.1 \times 10^{-5}$ is determined at $90\%$ confidence level.

The resonance parameters of χc0, the 31P0 resonance of charmonium, have been measured at the Fermilab Antiproton Accumulator by means of the reaction ¯pp→χc0→γJ/ψ→γ(e+e−). The results are M(χc0)=3417.4+1.8−1.9±0.2MeV/c2, Γ(χc0)=16.6+5.2−3.7±0.1MeV, and Γ(χc0→¯pp)×B(χc0→J/ψγ)×B(J/ψ→e+e−)=2.89+0.67−0.53±0.14eV. Using known branching ratios we also obtain Γ(χc0→¯pp)=8.0+1.9+3.5−1.5−1.9keV. These results are discussed in relation to the other χcJ states and to theoretical predictions.Received 3 June 1999DOI:https://doi.org/10.1103/PhysRevLett.83.2902©1999 American Physical Society

Differential cross sections for pp elastic scattering have been measured for very small momentum transfers at six different incident antiproton momenta in the range 3.7 to 6.2 GeV/c by the detection of recoil protons at scattering angles close to 90°. Forward scattering parameters σT, b, and ϱ have been determined. For the ϱ-parameter, up to an order of magnitude higher level of precision has been achieved compared to that in earlier experiments. It is found that existing dispersion theory predictions are in disagreement with our results for the ϱ-parameter.

Fermilab experiment E835 has observed (-)pp annihilation production of the charmonium state chi(c0) and its subsequent decay into pi(0)pi(0). Although the resonant amplitude is an order of magnitude smaller than that of the nonresonant continuum production of pi(0)pi(0), an enhanced interference signal is evident. A partial wave expansion is used to extract physics parameters. The amplitudes J=0 and 2, of comparable strength, dominate the expansion. Both are accessed by L=1 in the entrance (-)pp channel. The product of the input and output branching fractions is determined to be B((-)pp-->chi(c0))xB(chi(c0)-->pi(0)pi(0))=(5.09+/-0.81+/-0.25)x10(-7).

The TOTEM collaboration has measured the proton-proton total cross section at $\sqrt{s}=13$ TeV with a luminosity-independent method. Using dedicated $β^{*}=90$ m beam optics, the Roman Pots were inserted very close to the beam. The inelastic scattering rate has been measured by the T1 and T2 telescopes during the same LHC fill. After applying the optical theorem the total proton-proton cross section is $σ_{\rm tot}=(110.6 \pm 3.4$) mb, well in agreement with the extrapolation from lower energies. This method also allows one to derive the luminosity-independent elastic and inelastic cross sections: $σ_{\rm el} = (31.0 \pm 1.7)$ mb and $σ_{\rm inel} = (79.5 \pm 1.8)$ mb.

In this work advanced TCAD (Technology Computer Aided Design) modeling will be used aiming at investigating the potentiality of Negative Capacitance (NC) devices in non-conventional application domains (e.g., radiation detection). A device-level approach to simulate the electrical characteristics of ferroelectric Hf0.5Zr0.5O2 (HZO) has been developed. The validation of the models and of the adopted numerical methods relies on the comparison between simulations and measurements of Metal-Ferroelectric-Metal and Metal-Ferroelectric-Insulator-Metal capacitors. By introducing the experimentally observed dielectric/ferroelectric interfacial trapped charges, our simulations are in a strong agreement with experimental measurements. These charges compensate the bound ferroelectric polarization charge when no external electric field is applied. The ferroelectric/dielectric interface could be therefore studied before and after X-ray irradiation. The goal will be to investigate the suitability of innovative NC devices to be used in High Energy Physics experiments detection systems, featuring self-amplified segmented, high granularity detectors.

The CMS and TOTEM experiments intend to carry out a joint diffractive/forward physics program with an unprecedented rapidity coverage. The present document outlines some aspects of such a physics program, which spans from the investigation of the low-x structure of the proton to the diffractive production of a SM or MSSM Higgs boson.

We use $(121\ifmmode\pm\else\textpm\fi{}1)$ million $\mathrm{\ensuremath{\Upsilon}}(3S)$ and $(98\ifmmode\pm\else\textpm\fi{}1)$ million $\mathrm{\ensuremath{\Upsilon}}(2S)$ mesons recorded by the BABAR detector at the PEP-II ${e}^{+}{e}^{\ensuremath{-}}$ collider at SLAC to perform a study of radiative transitions involving the ${\ensuremath{\chi}}_{b\mathrm{J}}(1P,2P)$ states in exclusive decays with ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}\ensuremath{\gamma}\ensuremath{\gamma}$ final states. We reconstruct twelve channels in four cascades using two complementary methods. In the first we identify both signal photon candidates in the electromagnetic calorimeter (EMC), employ a calorimeter timing-based technique to reduce backgrounds, and determine branching-ratio products and fine mass splittings. These results include the best observational significance yet for the ${\ensuremath{\chi}}_{b0}(2P)\ensuremath{\rightarrow}\ensuremath{\gamma}\mathrm{\ensuremath{\Upsilon}}(2S)$ and ${\ensuremath{\chi}}_{b0}(1P)\ensuremath{\rightarrow}\ensuremath{\gamma}\mathrm{\ensuremath{\Upsilon}}(1S)$ transitions. In the second method, we identify one photon candidate in the EMC and one which has converted into an ${e}^{+}{e}^{\ensuremath{-}}$ pair due to interaction with detector material, and we measure absolute product branching fractions. This method is particularly useful for measuring $\mathrm{\ensuremath{\Upsilon}}(3S)\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\chi}}_{b1,2}(1P)$ decays. Additionally, we provide the most up-to-date derived branching fractions, matrix elements and mass splittings for ${\ensuremath{\chi}}_{b}$ transitions in the bottomonium system. Using a new technique, we also measure the two lowest-order spin-dependent coefficients in the nonrelativistic QCD Hamiltonian.

The pbar p -&gt; Ks Ks -&gt; 4pi+/- cross section was measured at incident antiproton momenta between 0.6 and 1.9 GeV/c using the CERN Low Energy Antiproton Ring (LEAR). This investigation was part of a systematic study of in-flight antiproton-proton annihilations into two-neutral-meson final states in a search for hadronic resonances. A coarse scan of the pbar p -&gt; Ks Ks cross section as a function of center-of-mass energy between 1.964 and 2.395 GeV/c^2 and a fine scan of the region surrounding the Xi(2220) are presented. Upper limits on the product branching ratio BR(Xi -&gt; pbar p)BR(Xi -&gt; Ks Ks) are determined for a wide range of mass and width assumptions based on the non-observation of the Xi(2220). A rise in the pbar p -&gt; Ks Ks cross section is observed near 2.15 GeV/c^2, which is consistent with the f2(2150) resonance.

The BaBar Collaboration has operated an instrumented flux return (IFR) system covering over 2000m2 with resistive plate chambers (RPCs) for nearly 3 years. The chambers are constructed of bakelite sheets separated by 2mm. The inner surfaces are coated with linseed oil. This system provides muon and neutral hadron detection for BaBar. Installation and commissioning were completed in 1998, and operation began mid-year 1999. While initial performance of the system reached design, over time, a significant fraction of the RPCs demonstrated significant degradation, marked by increased currents and reduced efficiency. A coordinated effort of investigations have identified many of the elements responsible for the degradation. This article presents our current understanding of the aging process of the BaBar RPCs along with the action plan to combat performance degradation of the IFR system.

We report on the decay to two photons of the χ c 0 (1 3 P 0 ) charmonium resonance formed in pp interactions at Fermilab experiment E835.We have measured the product of branching ratios BR(χ c 0 → pp) × BR(χ c 0 → γ γ ) = (6.52 ± 1.18(stat) +0.48 -0.72 (sys)) × 10 -8 .Using values from the 2002 PDG, this measurement leads to the partial width Γ (χ c 0 → γ γ ) = 2.9 ± 0.9 keV.

The TOTEM experiment at the LHC has performed the first measurement at $\sqrt{s} = 13$ TeV of the $\rho$ parameter, the real to imaginary ratio of the nuclear elastic scattering amplitude at $t=0$, obtaining the following results: $\rho = 0.09 \pm 0.01$ and $\rho = 0.10 \pm 0.01$, depending on different physics assumptions and mathematical modelling. The unprecedented precision of the $\rho$ measurement, combined with the TOTEM total cross-section measurements in an energy range larger than 10 TeV (from 2.76 to 13 TeV), has implied the exclusion of all the models classified and published by COMPETE. The $\rho$ results obtained by TOTEM are compatible with the predictions, from alternative theoretical models both in the Regge-like framework and in the QCD framework, of a colourless 3-gluon bound state exchange in the $t$-channel of the proton-proton elastic scattering. On the contrary, if shown that the 3-gluon bound state $t$-channel exchange is not of importance for the description of elastic scattering, the $\rho$ value determined by TOTEM would represent a first evidence of a slowing down of the total cross-section growth at higher energies. The very low-$|t|$ reach allowed also to determine the absolute normalisation using the Coulomb amplitude for the first time at the LHC and obtain a new total proton-proton cross-section measurement $\sigma_{tot} = 110.3 \pm 3.5$ mb, completely independent from the previous TOTEM determination. Combining the two TOTEM results yields $\sigma_{tot} = 110.5 \pm 2.4$ mb.

We report a search for the decay ${\overline B}^{0}\rightarrow{\Lambda_{\rm c}^{+}}{\overline p}{p}{\overline p}$. Using a data sample of $471 \times 10^6\: B{\overline B}$ pairs collected with the BABAR detector at the PEP-II storage ring at SLAC, we find no events and set an upper limit on the branching fraction ${\cal B}({\overline B}^{0}\rightarrow{\Lambda_{\rm c}^{+}}{\overline p}{p}{\overline p}) \times\frac{{\cal B}(\Lambda_{\rm c}^{+}\rightarrow p K^{-} \pi^{+})}{0.050} < 2.8\times10^{-6}$ at $90\,%$ C.L., where we have normalized ${\cal B}(\Lambda_{\rm c}^{+}\rightarrow p K^{-} \pi^{+})$ to the world average value.

We describe searches for B meson decays to the charmless vector-vector final states omega omega and omega phi with 471 x 10^6 B Bbar pairs produced in e+ e- annihilation at sqrt(s) = 10.58 GeV using the BABAR detector at the PEP-II collider at the SLAC National Accelerator Laboratory. We measure the branching fraction B(B0 --> omega omega) = (1.2 +- 0.3 +0.3-0.2) x 10^-6, where the first uncertainty is statistical and the second is systematic, corresponding to a significance of 4.4 standard deviations. We also determine the upper limit B(B0 --> omega phi) < 0.7 x 10^-6 at 90% confidence level. These measurements provide the first evidence for the decay B0 --> omega omega, and an improvement of the upper limit for the decay B0 --> omega phi.

We have determined the following ${\ensuremath{\psi}}^{\ensuremath{'}}$ branching ratios using the large event sample collected by Fermilab experiment E835 in the reaction $p\overline{p}\ensuremath{\rightarrow}{\ensuremath{\psi}}^{\ensuremath{'}}:$ $\mathcal{B}({\ensuremath{\psi}}^{\ensuremath{'}}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}})=(7.4\ifmmode\pm\else\textpm\fi{}0.2\ifmmode\pm\else\textpm\fi{}0.7)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3},$ $\mathcal{B}({\ensuremath{\psi}}^{\ensuremath{'}}\ensuremath{\rightarrow}J/\ensuremath{\psi}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0})=(18.7\ifmmode\pm\else\textpm\fi{}0.9\ifmmode\pm\else\textpm\fi{}1.3)%$ and $\mathcal{B}({\ensuremath{\psi}}^{\ensuremath{'}}\ensuremath{\rightarrow}J/\ensuremath{\psi}\ensuremath{\eta})=(4.1\ifmmode\pm\else\textpm\fi{}0.3\ifmmode\pm\else\textpm\fi{}0.5)%.$

We report the observation of the baryonic decay ${\overline{B}}^{0}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\overline{p}{K}^{\ensuremath{-}}{K}^{+}$ using a data sample of $471\ifmmode\times\else\texttimes\fi{}1{0}^{6}$ $B\overline{B}$ pairs produced in ${e}^{+}{e}^{\ensuremath{-}}$ annihilations at $\sqrt{s}=10.58\text{ }\text{ }\mathrm{GeV}$. This data sample was recorded with the BABAR detector at the PEP-II storage ring at SLAC. We find $\mathcal{B}({\overline{B}}^{0}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\overline{p}{K}^{\ensuremath{-}}{K}^{+})=(2.5\ifmmode\pm\else\textpm\fi{}0.{4}_{(\text{stat})}\ifmmode\pm\else\textpm\fi{}0.{2}_{(\text{syst})}\ifmmode\pm\else\textpm\fi{}\phantom{\rule{0ex}{0ex}}0.{6}_{\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{c}^{+})})\ifmmode\times\else\texttimes\fi{}1{0}^{\ensuremath{-}5}$, where the uncertainties are statistical, systematic, and due to the uncertainty of the ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}p{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ branching fraction, respectively. The result has a significance corresponding to 5.0 standard deviations, including all uncertainties. For the resonant decay ${\overline{B}}^{0}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\overline{p}\ensuremath{\phi}$, we determine the upper limit $\mathcal{B}({\overline{B}}^{0}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\overline{p}\ensuremath{\phi})&lt;1.2\ifmmode\times\else\texttimes\fi{}1{0}^{\ensuremath{-}5}$ at 90% confidence level.

We describe in detail a previously published measurement of CP violation induced by B0-anti B0 oscillations, based on an integrated luminosity of 425.7 fb-1 collected by the BABAR experiment at the PEPII collider. We apply a novel technique to a sample of about 6 million B0bar -&gt; D*+ l- nubar decays selected with partial reconstruction of the D*+ meson. The charged lepton identifies the flavor of one B meson at its decay time, the flavor of the other B is determined by kaon tagging. We determine a CP violating asymmetry ACP = (0.0006 +- 0.0017 + 0.0038 - 0.0032). This measurement is consistent and competitive with those obtained at the B factories with dilepton events.

Abstract This work aims to investigate the suitability of innovative negative capacitance (NC) devices to be used in High Energy Physics experiments detection systems, featuring self-amplified, segmented, high granularity detectors. Within this framework, MFM (Metal-Ferroelectric-Metal) and MFIM (Metal-Ferroelectric-Insulator-Metal) structures have been investigated within the Technology-CAD environment. The strength of this approach is to exploit the behavior of a simple capacitor to accurately ad-hoc customize the TCAD library aiming at realistically modeling the polarization properties of devices fabricated with ferroelectric materials. The comparison between simulations and measurements in terms of polarization as a function of the applied electric field for both MFM and MFIM devices has been used for modeling and methodologies validation purposes. The analyses and results obtained for MFIM capacitors can be straightforwardly extended to the study of NC-FETs. This work would support the use of the TCAD modeling approach as a predictive tool to optimize the design and the operation of the new generation NC-FET devices for the future High Energy Physics experiments in the HL-LHC scenario. The NC working principle will be employed for particle detection applications in order to exceed the limits imposed by current CMOS technology in terms of power consumption, signal detectability and switching speed.

The BaBar Collaboration has operated a system covering over 2000 m/sup 2/ with resistive plate chambers for nearly three years. The chambers are constructed of bakelite sheets separated by 2 mm. The inner surfaces are coated with linseed oil. This system provides muon and neutral hadron detection for BaBar. Installation and commissioning were completed in 1998, and operation began mid-1999. While initial performance of the system reached design, over time, a significant fraction of the resistive plate chambers demonstrated significant degradation, marked by increased currents and reduced efficiency. A coordinated investigative effort has identified many of the elements responsible for the degradation.

I present preliminary results on the search for $h_c$ in its $\eta_c\gamma$ and $J/\psi\pi^0$ decay modes. We observe an excess of \eta_c\gamma$ events near 3526 MeV that has a probability ${\cal P} \sim 0.001$ to arise from background fluctations. The resonance parameters are $M=3525.8 \pm 0.2 \pm 0.2 $MeV, $\Gamma\leq$ 1 MeV, and $10.6\pm 3.7\pm3.4(br) < \Gamma_{\bar{p}p}B_{\eta_c\gamma} < 12.8\pm 4.8\pm4.5(br) $eV. We find no event excess within the search region in the $J/\psi\pi^0$ mode.

The muon and neutral hadron detector of the BaBar experiment for the PEP-II Asymmetric B-factory at SLAC uses Resistive Plate Counters (RPCs) as active detectors. A large fraction of the total system, which consists of approximately 800 chambers for an overall surface of 2000 m2, has already been built and tested in cosmic rays. Preliminary results of the operating characteristics with a new non-flammable and environmentally safe gas mixture are reported.

I present preliminary results on the search for hc in its ηcγ and J/ψπ0 decay modes. We observe an excess of ηcγ events near 3526 MeV that has a probability P∼0.001 to arise from background fluctations. The resonance parameters are M=3525.8±0.2±0.2MeV, Γ⩽1MeV, and 10.6±3.7±3.4(br)<Γp¯pBηcγ<12.8±4.8±4.5(br)eV. We find no event excess within the search region in the J/ψπ0 mode.

This article describes the Read Out Card (ROC) motherboard, which is the main component of the T1 forward telescope front-end electronic system. The ROC main objectives are to acquire tracking data and trigger information from the detector. It performs data conversion from electrical to optical format and transfers the data streams to the next level of the system and it implements Slow Control modules which are able to receive, decode and distribute the LHC machine low jitter clock and fast command. The ROC also provides a spy mezzanine connection based on programmable FPGA and USB2.0 for laboratory and portable DAQ debugging system.

The BaBar detector is currently operating nearly 200 Resistive Plate Chambers (RPCs), constructed as part of an upgrade of the forward endcap muon detector in 2002. Although the average RPC efficiency remains high, numerous changes in the RPC performance (increased currents and rates) have been observed. A few of the highest rate RPCs have suffered efficiency losses of more than 15%. Several types of efficiency loss have been observed. Tests with humidified gas have shown that some of the lost efficiency is recoverable. However, efficiency losses in the highest rate regions have not yet improved with humid gases.

Fermilab experiment E835 has studied reactions $\overline{p}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0},{\ensuremath{\pi}}^{0}\ensuremath{\eta},\ensuremath{\eta}\ensuremath{\eta},$ ${\ensuremath{\pi}}^{0}{\ensuremath{\eta}}^{\ensuremath{'}}$ and $\ensuremath{\eta}{\ensuremath{\eta}}^{\ensuremath{'}}$ in the energy region of the ${\ensuremath{\chi}}_{c0}({1}^{3}{P}_{0})$ from $3340$ MeV to $3470$ MeV. Interference between resonant and continuum production is observed in the ${\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}$ and $\ensuremath{\eta}\ensuremath{\eta}$ channels, and the product of the input and output branching fractions is measured. Limits on resonant production are set for the ${\ensuremath{\pi}}^{0}\ensuremath{\eta}$ and ${\ensuremath{\pi}}^{0}{\ensuremath{\eta}}^{\ensuremath{'}}$ channels. An indication of interference is observed in the $\ensuremath{\eta}{\ensuremath{\eta}}^{\ensuremath{'}}$ channel. The technique for extracting resonance parameters in an environment dominated by continuum production is described.

We have measured several branching ratios for ψ′ decay using the data collected by the FNAL E835 experiment during the year 2000, obtaining B(ψ′→e+e−)=0.0068±0.0001±0.0004, B(ψ′→J/ψπ+π−)=0.292±0.005±0.018, B(ψ′→J/ψπ0π0)=0.167±0.005±0.014, and B(ψ′→J/ψη)=0.028±0.002±0.002. We also present a measurement of the dipion mass distribution in the decays ψ′→J/ψππ.Received 6 August 2004DOI:https://doi.org/10.1103/PhysRevD.71.032006©2005 American Physical Society

The TOTEM experiment is dedicated to the measurement of the total proton–proton cross-section with the luminosity-independent method and the study of elastic and diffractive scattering processes. Two tracking telescopes, T1 and T2, integrated in the CMS detector, cover the pseudo-rapidity region between 3.1 and 6.5 on both sides of the interaction point IP5. The Roman Pot (RP) stations are located at distances of ±147 m and ±220 m with respect to the interaction point to measure the very forward scattered protons at very small angles. During the LHC technical stop in winter 2010/2011, the TOTEM experiment was completed with the installation of the T1 telescope and the RP stations at ±147 m. In 2011, the LHC machine provided special optics with the large ß⁎=90 m, allowing TOTEM to measure the elastic scattering differential cross-section, down to the four-momentum transfer squared |t|=2×10−2 GeV2. Using the optical theorem and extrapolation of the differential cross-section to t=0 (optical point), the total p–p cross-section at the LHC energy of s=7TeV could be computed for the first time. Furthermore we measured with standard LHC beam optics and the energy of s=7TeV the forward charged particle pseudorapidity density dn/dη in the range of 5.3<|η|<6.4. The status of the experiment, the performance of the detectors with emphasis on the RPs are described and the first physics results are presented.

We report on a search in ${e}^{+}{e}^{\ensuremath{-}}$ annihilations for new ${\ensuremath{\pi}}^{0}$-like particles produced in association with a $\ensuremath{\tau}$-lepton pair. These objects, with a similar mass and similar decay modes to ${\ensuremath{\pi}}^{0}$ mesons, could provide an explanation for the non-asymptotic behavior of the pion-photon transition form factor observed by the BABAR Collaboration. No significant signal is observed, and limits on the production cross section at the level of 73 fb or 370 fb, depending on the model parameters, are determined at 90% confidence level. These upper limits lie below the cross section values needed to explain the BABAR form factor data.

Abstract The IFR system is a RPC-based detector used to identify muons and neutral hadrons in the BaBar experiment at PEP II machine in SLAC. The RPC system can be used to reconstruct the trajectory of muons, pions and neutral hadrons interacting in the iron of the IFR. The different range and hit pattern allow to discriminate different particles crossing the IFR. An overview of the system design and the preliminary results on the IFR performances are reported.

Recent results from on hadronic spectroscopy are presented, based on data collected by the BaBar experiment between 1999 and 2004. The properties of the recently discovered D*{sub sJ}(2317){sup +} and D{sub sJ}(2460){sup +} states are studied: resonance parameters and ratios of decay rates are measured from continuum e{sup +}e{sup -} production, and production rates are measured from B decays. A search for the D*{sub sJ}(2632){sup +} state whose observation has been recently reported by the SELEX Collaboration, and a search for a charged partner of the charmonium-like X(3872) state, are performed, yielding negative results. Finally, extensive searches for several pentaquark candidates, both fully inclusive and in B decays, result in no positive evidence.

Recent results are presented on the study of the η c and η c (2S) resonance parameters and on the observation of two narrow states in the D s spectrum, using the BaBar data set. The η c and η c (2S) are produced in γ γ interactions: a precision measurement of their mass and total width is reported, together with a study supporting the correct assignment of the η c (2S) quantum numbers. Two states $D^{*+}_{sJ\ 2317}$ , $D_{sJ\ 2457}^+$ are observed in continuum e+e– production, decaying to D+ s π0 and D+ s π0γ respectively: their masses are measured and a study on the resonant structure of the D+ sJ (2457) decay is reported. All results are preliminary Except for the of (2317) mass determination. . PACS: PACS-13.66.Bc – PACS-14.40.Gx – PACS-14.40.Lb

The T1 detector of the TOTEM experiment is devoted to the measurement of the inelastic rate of proton–proton interactions at the LHC. It is made of Cathode Strip Chambers. The complete electronic chains of front-end, readout and trigger are presented here. The electronics system has been developed keeping into account the hostile environment from the point of view of both radiation and magnetic field. Dedicated VLSI circuits have been extensively used in order to optimize space and power consumption.

The High-Luminosity LHC (HL-LHC) upgrade of the CMS pixel detector will require the development of novel pixel sensors which can withstand the increase in instantaneous luminosity to L=5×1034 cm−2s−1 and collect ∼ 3000 fb−1 of data. The innermost layer of the pixel detector will be exposed to doses of about 1016 neq/ cm2. Hence, new pixel sensors with improved radiation hardness need to be investigated. A variety of silicon materials (Float-zone, Magnetic Czochralski and Epitaxially grown silicon), with thicknesses from 50 μm to 320 μm in p-type and n-type substrates have been fabricated using single-sided processing. The effect of reducing the sensor active thickness to improve radiation hardness by using various techniques (deep diffusion, wafer thinning, or growing epitaxial silicon on a handle wafer) has been studied. The results for electrical characterization, charge collection efficiency, and position resolution of various n-on-p pixel sensors with different substrates and different pixel geometries (different bias dot gaps and pixel implant sizes) will be presented.

The TOTEM experiment is dedicated to the measurement of the total proton-proton cross-section with the luminosity-independent method and the study of elastic and diffractive scattering processes. Two tracking telescopes, T1 and T2, integrated in the CMS detector, cover the pseudo-rapidity region between 3.1 and 6.5 on both sides of the interaction point IP5. The Roman Pot (RP) stations are located at distances of ± 147m and ± 220 m with respect to the interaction point to measure the very forward scattered protons at very small angles. During the LHC technical stop in winter 2010/2011, the TOTEM experiment was completed with the installation of the T1 telescope and the RP stations at ± 147 m. In 2011, the LHC machine provided special optics with the large ß* = 90 m, allowing TOTEM to measure the elastic scattering differential cross section, down to the four-momentum transfer squared |t| = 2×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−2</sup> GeV <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Using the optical theorem and extrapolation of the differential cross section to t = 0 (optical point), the total p-p cross section at the LHC energy of √v = 7 TeV could be computed for the first time. The status of the experiment, the performance of the detectors with emphasis on the RPs are described and the first physics results are presented.