J. Cuevas

The mass of the W boson, a mediator of the weak force between elementary particles, is tightly constrained by the symmetries of the standard model of particle physics. The Higgs boson was the last missing component of the model. After observation of the Higgs boson, a measurement of the W boson mass provides a stringent test of the model. We measure the W boson mass, MW, using data corresponding to 8.8 inverse femtobarns of integrated luminosity collected in proton-antiproton collisions at a 1.96 tera-electron volt center-of-mass energy with the CDF II detector at the Fermilab Tevatron collider. A sample of approximately 4 million W boson candidates is used to obtain [Formula: see text], the precision of which exceeds that of all previous measurements combined (stat, statistical uncertainty; syst, systematic uncertainty; MeV, mega-electron volts; c, speed of light in a vacuum). This measurement is in significant tension with the standard model expectation.

We present a new measurement of the inclusive forward-backward $t\overline{t}$ production asymmetry and its rapidity and mass dependence. The measurements are performed with data corresponding to an integrated luminosity of $5.3\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$, recorded with the CDF-II Detector at the Fermilab Tevatron. Significant inclusive asymmetries are observed in both the laboratory frame and the $t\overline{t}$ rest frame, and in both cases are found to be consistent with $CP$ conservation under interchange of $t$ and $\overline{t}$. In the $t\overline{t}$ rest frame, the asymmetry is observed to increase with the $t\overline{t}$ rapidity difference, $\ensuremath{\Delta}y$, and with the invariant mass ${M}_{t\overline{t}}$ of the $t\overline{t}$ system. Fully corrected parton-level asymmetries are derived in two regions of each variable, and the asymmetry is found to be most significant at large $\ensuremath{\Delta}y$ and ${M}_{t\overline{t}}$. For ${M}_{t\overline{t}}\ensuremath{\ge}450\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, the parton-level asymmetry in the $t\overline{t}$ rest frame is ${A}^{t\overline{t}}=0.475\ifmmode\pm\else\textpm\fi{}0.114$ compared to a next-to-leading order QCD prediction of $0.088\ifmmode\pm\else\textpm\fi{}0.013$.

DELPHI data collected at centre-of-mass energies up to 208 GeV have been analysed to search for charginos, neutralinos and sfermions in the framework of the Minimal Supersymmetric Standard Model (MSSM) with R-parity conservation. No evidence for a signal was found in any of the channels. The results of each search were used to derive limits on production cross-sections and particle masses. In addition, the combined result of all searches excludes regions in the parameter space of the constrained MSSM, leading to limits on the mass of the Lightest Supersymmetric Particle and other supersymmetric particles.

The production of single- and multi-photon events has been studied in the reaction e+e- -> gamma (gamma) + invisible particles. The data collected with the DELPHI detector during the years 1999 and 2000 at centre-of-mass energies between 191 GeV and 209 GeV was combined with earlier data to search for phenomena beyond the Standard Model. The measured number of light neutrino families was consistent with three and the absence of an excess of events beyond that predicted by the Standard Model processes was used to set limits on new physics. Both model-independent searches and searches for new processes predicted by supersymmetric and extra-dimensional models have been made. Limits on new non-standard model interactions between neutrinos and electrons were also determined.

We present new measurements of the inclusive forward-backward ttbar production asymmetry, AFB, and its dependence on several properties of the ttbar system. The measurements are performed with the full Tevatron data set recorded with the CDF II detector during ppbar collisions at sqrt(s) = 1.96 TeV, corresponding to an integrated luminosity of 9.4 fb^(-1). We measure the asymmetry using the rapidity difference Delta-y=y_(t)-y_(tbar). Parton-level results are derived, yielding an inclusive asymmetry of 0.164+/-0.047 (stat + syst). We observe a linear dependence of AFB on the top-quark pair mass M(ttbar) and the rapidity difference |Delta-y| at detector and parton levels. Assuming the standard model, the probabilities to observe the measured values or larger for the detector-level dependencies are 7.4*10^(-3) and 2.2*10^(-3) for M(ttbar) and |Delta-y| respectively. Lastly, we study the dependence of the asymmetry on the transverse momentum of the ttbar system at the detector level. These results are consistent with previous lower-precision measurements and provide additional quantification of the functional dependencies of the asymmetry.

We report a study of the invariant mass distribution of jet pairs produced in association with a W boson using data collected with the CDF detector which correspond to an integrated luminosity of 4.3 fb(-1). The observed distribution has an excess in the 120-160 GeV/c(2) mass range which is not described by current theoretical predictions within the statistical and systematic uncertainties. In this Letter, we report studies of the properties of this excess.

We have measured the W-boson mass MW using data corresponding to 2.2/fb of integrated luminosity collected in proton-antiproton collisions at 1.96 TeV with the CDF II detector at the Fermilab Tevatron collider. Samples consisting of 470126 W->enu candidates and 624708 W->munu candidates yield the measurement MW = 80387 +- 12 (stat) +- 15 (syst) = 80387 +- 19 MeV. This is the most precise measurement of the W-boson mass to date and significantly exceeds the precision of all previous measurements combined.

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We report a measurement of the difference (Delta Acp) between time-integrated CP--violating asymmetries in D0-> K+ K- and D0-> pi+pi- decays reconstructed in the full data set of proton-antiproton collisions collected by the Collider Detector at Fermilab, corresponding to 9.7 fb-1 of integrated luminosity. The strong decay D*+->D0 pi+ is used to identify the charm meson at production as D0 or anti-D0. We measure Delta Acp = [-0.62 +- 0.21 (stat) +- 0.10 (syst)] %, which differs from zero by 2.7 Gaussian standard deviations.This result supports similar evidence for CP violation in charm-quark decays obtained in proton-proton collisions.

We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.

A search has been performed for B(s)(0) → μ+ μ- and B(0) → μ+ μ- decays using 7 fb(-1) of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron collider. The observed number of B(0) candidates is consistent with background-only expectations and yields an upper limit on the branching fraction of B(B(0) → μ+ μ-) < 6.0 × 10(-9) at 95% confidence level. We observe an excess of B(s)(0) candidates. The probability that the background processes alone could produce such an excess or larger is 0.27%. The probability that the combination of background and the expected standard model rate of B(s)(0) → μ+ μ- could produce such an excess or larger is 1.9%. These data are used to determine B(B(s)(0)→ μ+ μ-) = (1.8(-0.9) (+1.1)) × 10(-8) and provide an upper limit of B(B(s)(0) → μ+ μ-) < 4.0 × 10(-8) at 95% confidence level.

We report on a measurement of CP-violating asymmetries (Acp) in the Cabibbo-suppressed D0 --> pi+ pi- and D0 --> K+K- decays reconstructed in a data sample corresponding to 5.9 fb-1 of integrated luminosity collected by the upgraded Collider Detector at Fermilab. We use the strong decay D*+ --> D0 pi+ to identify the flavor of the charmed meson at production and exploit CP-conserving strong c-cbar pair-production in p-pbar collisions. High-statistics samples of Cabibbo-favored D0 --> K- p+ decays with and without a D* tag are used to correct for instrumental effects and significantly reduce systematic uncertainties. We measure Acp(D0 --> pi+ pi-) = (+0.22 +- 0.24 (stat) +- 0.11 (syst))% and Acp(D 0 --> K+ K-) = (-0.24 +- 0.22 (stat) +- 0.09 (syst))%, in agreement with CP conservation. These are the most precise determinations from a single experiment to date. Under the assumption of negligible direct CP violation in D0 --> pi+ pi- and D0 --> K+K- decays, the results provide an upper limit to the CP-violating asymmetry in D0 mixing, |Acp^{ind}(D0)|< 0.13% at the 90% confidence level.

We present the results of a search for dark matter production in the monojet signature. We analyze a sample of Tevatron $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ corresponding to an integrated luminosity of $6.7\text{ }\text{ }\mathrm{f}{\mathrm{b}}^{\ensuremath{-}1}$ recorded by the CDF II detector. In events with large missing transverse energy and one energetic jet, we find good agreement between the standard model prediction and the observed data. We set 90% confidence level upper limits on the dark matter production rate. The limits are translated into bounds on nucleon-dark matter scattering rates which are competitive with current direct detection bounds on spin-independent interaction below a dark matter candidate mass of $5\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, and on spin-dependent interactions up to masses of $200\text{ }\text{ }\mathrm{GeV}/{c}^{2}$.

Using the full CDF Run II data sample, we report evidence for a new resonance, which we refer to as $B(5970)$, found simultaneously in the ${B}^{0}{\ensuremath{\pi}}^{+}$ and ${B}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ mass distributions with a significance of 4.4 standard deviations. We further report the first study of resonances consistent with orbitally excited ${B}^{+}$ mesons and an updated measurement of the properties of orbitally excited ${B}^{0}$ and ${B}_{s}^{0}$ mesons. We measure the masses and widths of all states, as well as the relative production rates of the ${B}_{1}$, ${B}_{2}^{*}$, and $B(5970)$ states and the branching fraction of the ${B}_{s2}^{*0}$ state to either ${B}^{*+}{K}^{\ensuremath{-}}$ and ${B}^{+}{K}^{\ensuremath{-}}$. Furthermore, we measure the production rates of the orbitally excited ${B}^{0,+}$ states relative to the ${B}^{0,+}$ ground state. The masses of the new $B(5970)$ resonances are $5978\ifmmode\pm\else\textpm\fi{}5(\text{stat})\ifmmode\pm\else\textpm\fi{}12(\text{syst})\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ for the neutral state and $5961\ifmmode\pm\else\textpm\fi{}5(\text{stat})\ifmmode\pm\else\textpm\fi{}12(\text{syst})\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ for the charged state, assuming that the resonance decays into $B\ensuremath{\pi}$ final states. The properties of the orbitally excited and the new $B(5970{)}^{0,+}$ states are compatible with isospin symmetry.

The observation of the [Formula: see text] structure in [Formula: see text] decays produced in [Formula: see text] collisions at [Formula: see text] TeV is reported with a statistical significance greater than 5 standard deviations. A fit to the [Formula: see text] mass spectrum is performed assuming the presence of a Breit–Wigner resonance. The fit yields a signal of [Formula: see text] resonance events, and resonance mass and width of [Formula: see text] and [Formula: see text], respectively. The parameters of this resonance-like structure are consistent with values reported from an earlier CDF analysis.

We report the most sensitive direct search for pair production of fourth-generation bottomlike chiral quarks (b') each decaying promptly to tW. We search for an excess of events with an electron or muon, at least five jets (one identified as due to a b or c quark), and an imbalance of transverse momentum by using data from pp collisions collected by the CDF II detector at Fermilab with an integrated luminosity of 4.8 fb(-1). We observe events consistent with background expectation, calculate upper limits on the b' pair-production cross section (σ(bb')) ≲30 fb for m(b') > 375 GeV/c2), and exclude m(b') < 372 GeV/c2 at 95% confidence level assuming a 100% branching ratio of b' to tW.

We present a study of Bs0 decays to the CP-odd final state J/psi f0(980) with J/psi -> mu+ mu- and f0(980) -> pi+ pi-. Using ppbar collision data with an integrated luminosity of 3.8/fb collected by the CDF II detector at the Tevatron we measure a Bs0 lifetime of tau(Bs0 -> J/psi f0(980)) = 1.70 -0.11+0.12(stat) +-0.03(syst) ps. This is the first measurement of the Bs0 lifetime in a decay to a CP eigenstate and corresponds in the standard model to the lifetime of the heavy Bs0 eigenstate. We also measure the product of branching fractions of Bs0 -> J/psi f0(980) and f0(980) -> pi+ pi- relative to the product of branching fractions of Bs0 -> J/psi phi and phi -> K+ K- to be R_f0/phi = 0.257 +_0.020(stat) +-0.014(syst), which is the most precise determination of this quantity to date.

We present a precision measurement of the top-quark mass using the full sample of Tevatron $\sqrt{s}=1.96$ TeV proton-antiproton collisions collected by the CDF II detector, corresponding to an integrated luminosity of 8.7 $fb^{-1}$. Using a sample of $t\bar{t}$ candidate events decaying into the lepton+jets channel, we obtain distributions of the top-quark masses and the invariant mass of two jets from the $W$ boson decays from data. We then compare these distributions to templates derived from signal and background samples to extract the top-quark mass and the energy scale of the calorimeter jets with {\it in situ} calibration. The likelihood fit of the templates from signal and background events to the data yields the single most-precise measurement of the top-quark mass, $\mtop = 172.85 $\pm$ 0.71 (stat) $\pm$ 0.85 (syst) GeV/c^{2}.$

We report measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb-1 of integrated luminosity, we obtain the first measurements of direct CP violation in bottom strange mesons, A_CP(BsKpi) = +0.39 +- 0.15 stat +- 0.08 syst, and bottom baryons, A_CP(Lb->ppi) = +0.03 +- 0.17 stat +- 0.05 syst and A_CP(Lb->pK) = +0.37 +- 0.17 +- 0.03 syst. In addition, we measure CP violation in Bd-->Kpi decays with 3.5sigma significance, A_CP(B->Kpi) = -0.086 +- 0.023 stat +- 0.009 syst, in agreement with the current world average. Measurements of branching fractions of Bs-->K+K- and B0-->pi+pi- decays are also updated.

The stopping power of ${\mathrm{H}}_{2}$ gas for the atomic component of a hydrogen beam in charge equilibrium has been measured by placing the stopping cell in an intense transverse magnetic field. This allows only those particles to reach the exit which have entered as neutrals and have not experienced any collision, as a result of which they became electrically charged. These neutrals are partially converted to protons in a subsequent gas stripper cell, and their energy measured in an electrostatic deflector. As ${\mathrm{H}}_{2}$ gas is admitted to the stripping cell, there is a rapid decay in beam intensity, since at each charge-changing collision the particle is extracted from the beam by the magnetic field. By counting individual exit particles, however, a beam diminution factor of ${10}^{\ensuremath{-}7}$ is acceptable and a well-defined energy group is detected which has experienced a loss of approximately 1% of its energy, and for which the stopping power ${\ensuremath{\epsilon}}_{0}$ of ${\mathrm{H}}_{2}$ gas, for instance at 50 keV, is only 0.42 of the conventional $\ensuremath{\epsilon}$, measured with the field off. The values of $\ensuremath{\epsilon}$ reported agree with those of Reynolds, Dunbar, Wenzel, and Whaling. The results for ${\ensuremath{\epsilon}}_{0}$ and $\frac{{\ensuremath{\epsilon}}_{0}}{\ensuremath{\epsilon}}$ are: Above 50 keV the experimental ${\ensuremath{\epsilon}}_{0}$ values agree well with those theoretically calculated by Dalgarno and Griffing for atomic hydrogen gas; at lower energies the experimental values are somewhat higher.

Beams of ${\mathrm{Li}}^{+}$ ions accelerated to kinetic energies in the range 10-475 kev were brought into charge equilibrium in the gases ${\mathrm{H}}_{2}$, He, and ${\mathrm{N}}_{2}$ and the fractional amounts of ${\mathrm{Li}}^{\ensuremath{-}}$, ${\mathrm{Li}}^{0}$, ${\mathrm{Li}}^{+}$, ${\mathrm{Li}}^{++}$, ${\mathrm{Li}}^{+++}$ measured. Because of the relatively large amount of ${\mathrm{Li}}^{\ensuremath{-}}$ in an equilibrated beam below 40 kev in energy in propane and nitrous oxide, limited investigations were carried out in these gases. The anomalously large ${\mathrm{Li}}^{++}$ yield in helium at ${\mathrm{Li}}^{7}$ energies below 100 kev was noted.By holding each separated charged constituent successively in an orbit in a magnetic field, admitting gas, and observing the beam attenuation, the total cross section for all charge-changing collisions was observed. Through application of the differential equations for growth or decay of a charged component, certain individual charge-changing cross sections can be deduced from these observed sums. Values are given for (${\ensuremath{\sigma}}_{\overline{1}0}+{\ensuremath{\sigma}}_{\overline{1}1}$), ${\ensuremath{\sigma}}_{01}$, ${\ensuremath{\sigma}}_{10}$, ${\ensuremath{\sigma}}_{12}$, ${\ensuremath{\sigma}}_{21}$, and (${\ensuremath{\sigma}}_{32}+{\ensuremath{\sigma}}_{31}$) in ${\mathrm{H}}_{2}$, He, and ${\mathrm{N}}_{2}$ target gases throughout the energy range. Upper limits can be assigned to ${\ensuremath{\sigma}}_{0\overline{1}}$, ${\ensuremath{\sigma}}_{1\overline{1}}$, ${\ensuremath{\sigma}}_{13}$, and ${\ensuremath{\sigma}}_{23}$. Use of data on ${\ensuremath{\sigma}}_{1\overline{1}}$ in ${\mathrm{H}}_{2}$ from other sources provides values of ${\ensuremath{\sigma}}_{0\overline{1}}$ in that gas. Values for ${\ensuremath{\sigma}}_{21}$ for ${\mathrm{Li}}^{++}$ in helium gas, compared, at common velocities, with ${\ensuremath{\sigma}}_{10}$ for ${\mathrm{He}}^{+}$ in helium, and ${\ensuremath{\sigma}}_{0\overline{1}}$ for ${\mathrm{H}}^{0}$ in helium, show the exchange nature of the ${\mathrm{He}}^{+}$He interaction compared to that of the other isoelectronic structures.

The silicon strip microvertex detector of the DELPHI experiment at the CERN LEP collider has been recently upgraded from two coordinates (RΦ only) to three coordinates reconstruction (RΦ and z). The new Microvertex detector consists of 125 952 readout channels, and uses novel techniques to obtain the third coordinate. These include the use of AC coupled double sided silicon detectors with strips orthogonal to each other on opposite sides of the detector wafer. The routing of signals from the z strips to the end of the detector modules is done with a second metal layer on the detector surface, thus keeping the material in the sensitive area to a minimum. Pairs of wafers are daisy chained, with the wafers within each pair flipped with respect to each other in order to minimize the load capacitance on the readout amplifiers. The design of the detector and its various components are described. Results on the performance of the new detector are presented, with special emphasis on alignment, intrinsic precision and impact parameter resolution. The new detector has been taking data since spring of 1994, performing up to design specifications.

Assessing genetic biodiversity and population structure of minor breeds through the information provided by neutral molecular markers, allows determination of their extinction risk and to design strategies for their management and conservation. Analysis of microsatellite loci is known to be highly informative in the reconstruction of the historical processes underlying the evolution and differentiation of animal populations. Guadarrama goat is a threatened Spanish breed which actual census (2008) consists of 3057 females and 203 males distributed in 22 populations more or less isolated. The aim of this work is to study the genetic status of this breed through the analysis of molecular data from 10 microsatellites typed in historic and actual live animals. The mean expected heterozygosity across loci within populations ranged from 0.62 to 0.77. Genetic differentiation measures were moderate, with a mean FST of 0.074, GST of 0.081 and RST of 0.085. Percentages of variation among and within populations were 7.5 and 92.5, respectively. Bayesian clustering analyses pointed out a population subdivision in 16 clusters, however, no correlation between geographical distances and genetic differences was found. Management factors such as the limited exchange of animals between farmers (estimated gene flow Nm = 3.08) mostly due to sanitary and social constraints could be the major causes affecting Guadarrama goat population subdivision. Genetic diversity measures revealed a good status of biodiversity in the Guadarrama goat breed. Since diseases are the first cause affecting the census in this breed, population subdivision would be an advantage for its conservation. However, to maintain private alleles present at low frequencies in such small populations minimizing the inbreeding rate, it would necessitate some mating designs of animals carrying such alleles among populations. The systematic use of molecular markers will facilitate the comprehensive management of these populations, which in combination with the actual breeding program to increase milk yield, will constitute a good strategy to preserve the breed.

We report measurements of the resonance properties of ${\ensuremath{\Lambda}}_{c}(2595{)}^{+}$ and ${\ensuremath{\Lambda}}_{c}(2625{)}^{+}$ baryons in their decays to ${\ensuremath{\Lambda}}_{c}^{+}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ as well as ${\ensuremath{\Sigma}}_{c}(2455{)}^{++,0}$ and ${\ensuremath{\Sigma}}_{c}(2520{)}^{++,0}$ baryons in their decays to ${\ensuremath{\Lambda}}_{c}^{+}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$ final states. These measurements are performed using data corresponding to $5.2\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity from $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$, collected with the CDF II detector at the Fermilab Tevatron. Exploiting the largest available charmed baryon sample, we measure masses and decay widths with uncertainties comparable to the world averages for ${\ensuremath{\Sigma}}_{c}$ states, and significantly smaller uncertainties than the world averages for excited ${\ensuremath{\Lambda}}_{c}^{+}$ states.

The transverse momentum cross section of ${e}^{+}{e}^{\ensuremath{-}}$ pairs in the $Z$-boson mass region of $66--116\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ is precisely measured using Run II data corresponding to $2.1\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity recorded by the Collider Detector at Fermilab. The cross section is compared with two quantum chromodynamic calculations. One is a fixed-order perturbative calculation at $\mathcal{O}({\ensuremath{\alpha}}_{s}^{2})$, and the other combines perturbative predictions at high transverse momentum with the gluon resummation formalism at low transverse momentum. Comparisons of the measurement with calculations show reasonable agreement. The measurement is of sufficient precision to allow refinements in the understanding of the transverse momentum distribution.

The angular distributions of muons from Υ(1S,2S,3S) → μ+ μ- decays are measured using data from pp collisions at sqrt[s] = 1.96 TeV corresponding to an integrated luminosity of 6.7 fb(-1) and collected with the CDF II detector at the Fermilab Tevatron. This analysis is the first to report the full angular distributions as functions of transverse momentum p(T) for Υ mesons in both the Collins-Soper and s-channel helicity frames. This is also the first measurement of the spin alignment of Υ(3S) mesons. Within the kinematic range of Υ rapidity |y|<0.6 and p(T) up to 40 GeV/c, the angular distributions are found to be nearly isotropic.

The $t\overline{t}$ spin correlation at production is a fundamental prediction of QCD and a potentially incisive test of new physics coupled to top quarks. We measure the $t\overline{t}$ spin state in $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ using 1001 candidate events in the lepton plus jets decay channel reconstructed in the CDF II detector. In the helicity basis, for a top-quark mass of $172.5\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, we find a spin correlation coefficient $\ensuremath{\kappa}=0.60\ifmmode\pm\else\textpm\fi{}0.50\text{ }\text{ }(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.16\text{ }\text{ }(\mathrm{syst})$, consistent with the QCD prediction, $\ensuremath{\kappa}\ensuremath{\approx}0.40$.

We report on the first measurement of the angular distributions of final state electrons in $p\bar{p}\to \gamma^{*}/Z\to e^{+}e^{-}+X$ events produced in the $Z$ boson mass region at $\sqrt{s}=1.96$ TeV. The data sample collected by the CDF II detector for this result corresponds to 2.1 fb$^{-1}$ of integrated luminosity. The angular distributions are studied as a function of the transverse momentum of the electron-positron pair and show good agreement with the Lam-Tung relation, consistent with a spin-1 description of the gluon, and demonstrate that at high values of the transverse momentum, $Z$ bosons are produced via quark anti-quark annihilation and quark-gluon Compton processes.

The partial stopping power of a target material for an ion or an atom is the energy lost per target particle per ${\mathrm{cm}}^{2}$ in all types of collisions in which the ion or the atom is the projectile, with the exception of those collisions in which the projectile leaves with its charge changed. Partial atomic stopping powers of target gases for atoms are measured by imposing a strong transverse magnetic field on the stopping cell. For partial ionic stopping-power measurements, the ion beam is held in a circular orbit, closely defined by vanes and slits, as it traverses the stopping cell. The partial stopping powers ${\ensuremath{\epsilon}}_{0}$ (for ${\mathrm{He}}^{0}$ traversing ${\mathrm{H}}_{2}$ gas), ${\ensuremath{\epsilon}}_{1}$ (for ${\mathrm{He}}^{+}$), ${\ensuremath{\epsilon}}_{2}$ (for ${\mathrm{He}}^{++}$) have been measured in the kinetic energy range 40-460 keV, and new measurements of the ordinary, or total stopping power of ${\mathrm{H}}_{2}$ gas for helium from 40 to 220 keV have been made. Using the known charge composition of He beams in ${\mathrm{H}}_{2}$, it is possible to deduce the fraction of the stopping power losses due to charge changing collisions, and this varies from 37% at 140 keV to 27% at 400 keV. At 120 keV, the total energy loss in completing the charge changing cycle ${\mathrm{He}}^{+}$ \ensuremath{\rightarrow} ${\mathrm{He}}^{0}$ \ensuremath{\rightarrow} ${\mathrm{He}}^{+}$ is 95\ifmmode\pm\else\textpm\fi{}9 eV, rising to 117\ifmmode\pm\else\textpm\fi{}10 at 160 keV.

We report final measurements of direct $\mathit{CP}$--violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using the complete $\sqrt{s}=1.96$ TeV proton-antiproton collisions data set, corresponding to 9.3 fb$^{-1}$ of integrated luminosity, we measure $\mathcal{A}(\Lambda^0_b \rightarrow p\pi^{-}) = +0.06 \pm 0.07\mathrm{(stat)} \pm 0.03\mathrm{(syst)}$ and $\mathcal{A}(\Lambda^0_b \rightarrow pK^{-}) = -0.10 \pm 0.08\mathrm{(stat)} \pm 0.04\mathrm{(syst)}$, compatible with no asymmetry. In addition we measure the $\mathit{CP}$--violating asymmetries in $B^0_s \rightarrow K^{-}\pi^{+}$ and $B^0 \rightarrow K^{+}\pi^{-}$ decays to be $\mathcal{A}(B^0_s \rightarrow K^{-}\pi^{+}) = +0.22 \pm 0.07\mathrm{stat)} \pm 0.02\mathrm{(syst)}$ and $\mathcal{A}(B^0 \rightarrow K^{+}\pi^{-}) = -0.083\pm 0.013 \mathrm{(stat)} \pm 0.004\mathrm{(syst)}$, respectively, which are significantly different from zero and consistent with current world averages.

We measure the inclusive forward-backward asymmetry of the charged-lepton pseudorapidities from top-quark pairs produced in proton-antiproton collisions and decaying to final states that contain two charged leptons (electrons or muons). The data are collected with the Collider Detector at Fermilab and correspond to an integrated luminosity of 9.1 fb(-1). We measure the leptonic forward-backward asymmetry, A(FB)(ℓ), to be 0.072 ± 0.060 and the leptonic pair forward-backward asymmetry, A(FB)(ℓℓ), to be 0.076 ± 0.082. The measured values can be compared with the standard model predictions of A(FB)(ℓ) = 0.038 ± 0.003 and A(FB)(ℓℓ) = 0.048 ± 0.004, respectively. Additionally, we combine the A(FB)(ℓ) result with a previous determination from a final state with a single lepton and hadronic jets and obtain A(FB)(ℓ) = 0.090(-0.026)(+0.028).

A study of the substructure of jets with transverse momentum greater than 400 GeV/c produced in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron Collider and recorded by the CDF II detector is presented. The distributions of the jet mass, angularity, and planar flow are measured for the first time in a sample with an integrated luminosity of 5.95 fb^-1. The observed substructure for high mass jets is consistent with predictions from perturbative quantum chromodynamics.

A search for the exotic meson $X(5568)$ decaying into the $B^0_s \pi^{\pm}$ final state is performed using data corresponding to $9.6 \textrm{fb}^{-1}$ from $p{\bar p}$ collisions at $\sqrt{s} = 1960$ GeV recorded by the Collider Detector at Fermilab. No evidence for this state is found and an upper limit of 6.7\% at the 95\% confidence level is set on the fraction of $B^0_s$ produced through the $X(5568) \rightarrow B^0_s \, \pi^{\pm}$ process.

Ion beams of ${\mathrm{He}}^{+}$ and ${\mathrm{He}}^{++}$, in the kinetic energy range 100 to 450 kev, are held in arcs of circular orbits in a magnetic field. When a few microns of gas are admitted the beam is attenuated by charge-changing collisions, since with change of charge the ion is lost from its orbit. Cross sections for such charge-changing collisions are designated by ${\ensuremath{\sigma}}_{\mathrm{if}}$, where $i$ is the initial positive ionic charge in electron units and $f$ the charge after the collision. (${\ensuremath{\sigma}}_{10}+{\ensuremath{\sigma}}_{12}$) has been directly measured for ${\mathrm{He}}^{+}$ in hydrogen, helium, and air, and (${\ensuremath{\sigma}}_{21}+{\ensuremath{\sigma}}_{20}$) for ${\mathrm{He}}^{++}$ in the same gases.Other observers have measured the equilibrium ratio ${\mathrm{He}}^{+}$/${\mathrm{He}}^{++}$ attained in a field-free beam after many collisions, and combining these data with our observations allows calculation of ${\ensuremath{\sigma}}_{10}$ and ${\ensuremath{\sigma}}_{12}$ separately if one assumes ${\ensuremath{\sigma}}_{02}$ negligible compared to the other cross sections. The electron loss cross sections ${\ensuremath{\sigma}}_{12}$ increase with energy for helium and air throughout the measured region and are of the order ${10}^{\ensuremath{-}17}$ ${\mathrm{cm}}^{2}$; ${\ensuremath{\sigma}}_{12}$ for hydrogen vs energy shows a broad maximum at about 370 kev and 0.98\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}17}$ ${\mathrm{cm}}^{2}$ per hydrogen atom.The capture cross sections ${\ensuremath{\sigma}}_{10}$ decrease rapidly in the measured energy range and in the region 200-450 kev those measured in helium agree, within the estimated experimental error, with theoretical calculations of H. Schiff.In attempting the resolution of the sums (${\ensuremath{\sigma}}_{21}+{\ensuremath{\sigma}}_{20}$) into the separate cross sections it is found that the errors in the measurements accumulate to such an extent that the individual values become very unreliable. An auxiliary experiment designed to increase the accuracy of our knowledge of the separated capture cross sections ${\ensuremath{\sigma}}_{20}$ and ${\ensuremath{\sigma}}_{21}$ is in progress.

A search for pair-produced doubly charged Higgs bosons has been performed using the data collected by the DELPHI detector at LEP at centre-of-mass energies between 189 and 209 GeV. No excess is observed in the data with respect to the Standard Model background. A lower limit for the mass of 97.3 GeV/c2 at the 95% confidence level has been set for doubly charged Higgs bosons in left–right symmetric models for any value of the Yukawa coupling between the Higgs bosons and the τ leptons.

The DELPHI detector at LEP has been used to measure multi-muon bundles originating from cosmic ray interactions with air. The cosmic events were recorded in “parasitic mode” between individual e+e− interactions and the total live time of this data taking is equivalent to 1.6 × 106 s. The DELPHI apparatus is located about 100 m underground and the 84 metres rock overburden imposes a cutoff of about 52 GeV/c on muon momenta. The data from the large volume Hadron Calorimeter allowed the muon multiplicity of 54,201 events to be reconstructed. The resulting muon multiplicity distribution is compared with the prediction of the Monte Carlo simulation based on CORSIKA/QGSJET01. The model fails to describe the abundance of high multiplicity events. The impact of QGSJET internal parameters on the results is also studied.

Single photons detected by the DELPHI experiment at LEP2 in the years 1997–2000 are reanalysed to investigate the existence of a single extra dimension in a modified ADD scenario with slightly warped large extra dimensions. The data collected at centre-of-mass energies between 180 and 209 GeV for an integrated luminosity of ∼650 pb−1 agree with the predictions of the Standard Model and allow a limit to be set on graviton emission in one large extra dimension. The limit obtained on the fundamental mass scale M D is 1.69 TeV/c 2 at 95% CL, with an expected limit of 1.71 TeV/c 2.

A measurement of the W boson mass and width has been performed by the DELPHI collaboration using the data collected during the full LEP2 programme (1996–2000). The data sample has an integrated luminosity of 660 pb-1 and was collected over a range of centre-of-mass energies from 161 to 209 GeV. Results are obtained by applying the method of direct reconstruction of the mass of the W from its decay products in both the W+W-→ℓν̄ℓqq̄’ and W+W-→qq̄’q̄q’ channels. The W mass result for the combined data set is $M_W = 80.336 \pm0.055 ({\text{Stat.}}) \pm0.028 ({\text{Syst.}}) \pm0.025 ({\text{FSI}}) \pm0.009 ({\text{LEP}}) \text{GeV}/c^2, $ where FSI represents the uncertainty due to final state interaction effects in the qq̄’q̄q’ channel, and LEP represents that arising from the knowledge of the collision energy of the accelerator. The combined value for the W width is ${\Gamma_{W}} = 2.404 \pm0.140 ({\text{Stat.}}) \pm0.077 ({\text{Syst.}}) \pm0.065 ({\text{FSI}}) \text{GeV}/c^2. $ These results supersede all values previously published by the DELPHI collaboration.

A precision measurement of the top quark mass ${m}_{t}$ is obtained using a sample of $t\overline{t}$ events from $p\overline{p}$ collisions at the Fermilab Tevatron with the CDF II detector. Selected events require an electron or muon, large missing transverse energy, and exactly four high-energy jets, at least one of which is tagged as coming from a $b$ quark. A likelihood is calculated using a matrix element method with quasi-Monte Carlo integration taking into account finite detector resolution and jet mass effects. The event likelihood is a function of ${m}_{t}$ and a parameter ${\ensuremath{\Delta}}_{\mathrm{JES}}$ used to calibrate the jet energy scale in situ. Using a total of 1087 events in $5.6\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity, a value of ${m}_{t}=173.0\ifmmode\pm\else\textpm\fi{}1.2\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ is measured.

The nature of b-quark jet hadronisation has been investigated using data taken at the Z peak by the DELPHI detector at LEP. Two complementary methods are used to reconstruct the energy of weakly decaying b-hadrons, $E_{\mathrm{B}}^{\mathrm{weak}}$ . The average value of $x^{\mathrm{weak}}_{\mathrm{B}} = E_{\mathrm{B}}^{\mathrm{weak}}/E_{\mathrm{beam}}$ is measured to be 0.699±0.011. The resulting $x^{\mathrm{weak}}_{\mathrm{B}}$ distribution is then analysed in the framework of two choices for the perturbative contribution (parton shower and Next to Leading Log QCD calculation) in order to extract measurements of the non-perturbative contribution to be used in studies of b-hadron production in other experimental environments than LEP. In the parton shower framework, data favour the Lund model ansatz and corresponding values of its parameters have been determined within PYTHIA 6.156 from DELPHI data: $$a= 1.84^{+0.23}_{-0.21}\quad\mbox{and}\quad b=0.642^{+0.073}_{-0.063}~\mathrm{GeV}^{-2},$$ with a correlation factor ρ=92.2%. Combining the data on the b-quark fragmentation distributions with those obtained at the Z peak by ALEPH, OPAL and SLD, the average value of $x^{\mathrm{weak}}_{\mathrm{B}}$ is found to be 0.7092±0.0025 and the non-perturbative fragmentation component is extracted. Using the combined distribution, a better determination of the Lund parameters is also obtained: $$a= 1.48^{+0.11}_{-0.10}\quad\mbox{and}\quad b=0.509^{+0.024}_{-0.023}~\mathrm{GeV}^{-2},$$ with a correlation factor ρ=92.6%.

We present the first model independent search for three-jet hadronic resonances within multijet events in sqrt(s) = 1.96 TeV pp collisions at the Fermilab Tevatron using the CDF II detector. Pair production of supersymmetric gluinos and squarks with hadronic R-parity violating decays is employed as an example of a new physics benchmark for this signature. Selection criteria based on the kinematic properties of an ensemble of jet combinations within each event help to extract signal from copious QCD background. No significant excess outside the top quark mass window is observed in data with an integrated luminosity of 3.2 fb(-1). We place 95% confidence level limits on the production cross section σ(pp → XX')×BR(gg → 3 jet + 3 jet) where X, X' = g, q, or q, with q, q → g + jet, as a function of gluino mass, in the range of 77 GeV/c2 to 240 GeV/c2.

We present a measurement of the \CP-violating parameter \betas using approximately 6500 $\BsJpsiPhi$ decays reconstructed with the CDF\,II detector in a sample of $p\bar p$ collisions at $\sqrt{s}=1.96$ TeV corresponding to 5.2 fb$^{-1}$ integrated luminosity produced by the Tevatron Collider at Fermilab. We find the \CP-violating phase to be within the range $\betas \in [0.02, 0.52] \cup [1.08, 1.55]$ at 68% confidence level where the coverage property of the quoted interval is guaranteed using a frequentist statistical analysis. This result is in agreement with the standard model expectation at the level of about one Gaussian standard deviation. We consider the inclusion of a potential $S$-wave contribution to the $\Bs\to J/\psi K^+K^-$ final state which is found to be negligible over the mass interval $1.009 < m(K^+K^-)<1.028 \gevcc$. Assuming the standard model prediction for the \CP-violating phase \betas, we find the \Bs decay width difference to be $\deltaG = 0.075 \pm 0.035\,\textrm{(stat)} \pm 0.006\,\textrm{(syst)} \ps$. We also present the most precise measurements of the \Bs mean lifetime $\tau(\Bs) = 1.529 \pm 0.025\,\textrm{(stat)} \pm 0.012\,\textrm{(syst)}$ ps, the polarization fractions $|A_0(0)|^2 = 0.524 \pm 0.013\,\textrm{(stat)} \pm 0.015\,\textrm{(syst)}$ and $|A_{\parallel}(0)|^2 = 0.231 \pm 0.014\,\textrm{(stat)} \pm 0.015\,\textrm{(syst)}$, as well as the strong phase $\delta_{\perp}= 2.95 \pm 0.64\,\textrm{(stat)} \pm 0.07\,\textrm{(syst)} \textrm{rad}$. In addition, we report an alternative Bayesian analysis that gives results consistent with the frequentist approach.

We search for annihilation decay modes of neutral $b$ mesons into pairs of charmless charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 6 fb$^{-1}$ of integrated luminosity, we obtain the first evidence for the $B^0_s \to \pi^+\pi^-$ decay, with a significance of $3.7\sigma$, and a measured branching ratio $\mathcal{B}(B^0_s \to \pi^+\pi^-)= (0.57 \pm 0.15 (stat) \pm 0.10 (syst))\times 10^{-6}$. A search for the $B^0 \to K^+K^-$ mode in the same sample yields a significance of $2.0\sigma$, and a central value estimate $\mathcal{B}(B^0 \to K^+K^-)= (0.23 \pm 0.10 (stat) \pm 0.10 (syst))\times 10^{-6}$.

Using data from proton-antiproton collisions at Ecms=1.96 TeV recorded by the CDF II detector at the Fermilab Tevatron, evidence for the excited resonance state Lambda_b* is presented in its Lambda_b0 pi+ pi- decay, followed by the Lambda_b0 -->Lambda_c+ (-->proton K- pi+) pi- decays. The analysis is based on a data sample corresponding to an integrated luminosity of 9.6/fb collected by an online event selection based on charged-particle tracks displaced from the proton-antiproton interaction point. The significance of the observed signal is 3.5 Gaussian sigmas. The mass of the observed state is found to be 5919.22 +- 0.76 MeV in agreement with similar findings in proton-proton collision experiments.

We present a measurement of the total decay width of the top quark using events with top-antitop-quark pair candidates reconstructed in the final state with one charged lepton and four or more hadronic jets. We use the full Tevatron Run II data set of $\sqrt{s} = 1.96$ TeV proton-antiproton collisions recorded by the CDF II detector. The top-quark mass and the mass of the hadronically-decaying $W$ boson are reconstructed for each event and compared with distributions derived from simulated signal and background samples to extract the top-quark width (\gmt) and the energy scale of the calorimeter jets with {\it in-situ} calibration. For a top-quark mass $\mtop = \gevcc{172.5}$, we find $1.10<\gmt<\gev{4.05}$ at 68% confidence level, which is in agreement with the standard-model expectation of \gev{1.3} and is the most precise direct measurement of the top-quark width to date.

We present a search for neutral Higgs bosons $\ensuremath{\phi}$ decaying into $b\overline{b}$, produced in association with $b$ quarks in $p\overline{p}$ collisions. This process could be observable in supersymmetric models with high values of $\mathrm{tan}\ensuremath{\beta}$. The event sample corresponds to $2.6\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity collected with the CDF II detector at the Fermilab Tevatron collider. We search for an enhancement in the mass of the two leading jets in events with three jets identified as coming from $b$ quarks using a displaced vertex algorithm. A data-driven procedure is used to estimate the dijet mass spectrum of the nonresonant multijet background. The contributions of backgrounds and a possible Higgs boson signal are determined by a two-dimensional fit of the data, using the dijet mass together with an additional variable which is sensitive to the flavor composition of the three tagged jets. We set mass-dependent limits on $\ensuremath{\sigma}(p\overline{p}\ensuremath{\rightarrow}\ensuremath{\phi}b)\ifmmode\times\else\texttimes\fi{}\mathcal{B}(\ensuremath{\phi}\ensuremath{\rightarrow}b\overline{b})$ which are applicable for a narrow scalar particle $\ensuremath{\phi}$ produced in association with $b$ quarks. We also set limits on $\mathrm{tan}\ensuremath{\beta}$ in supersymmetric Higgs models including the effects of the Higgs boson width.

This Letter reports a measurement of the cross section for producing pairs of central prompt isolated photons in proton-antiproton collisions at a total energy of 1.96 TeV using data corresponding to 9.5/fb integrated luminosity collected with the CDF II detector at the Fermilab Tevatron. The measured differential cross section is compared to three calculations derived from the theory of strong interactions. These include a prediction based on a leading order matrix element calculation merged with parton shower, a next-to-leading order, and a next-to-next-to-leading order calculation. The first and last calculations reproduce most aspects of the data, thus showing the importance of higher-order contributions for understanding the theory of strong interaction and improving measurements of the Higgs boson and searches for new phenomena in diphoton final states.

We measure the asymmetry in the charge-weighted rapidity of the lepton in semileptonic ttbar decays recorded with the CDF II detector using the full Tevatron Run II sample, corresponding to an integrated luminosity of 9.4/fb. A parametrization of the asymmetry as a function of the charge-weighted rapidity is used to correct for the finite acceptance of the detector and recover the production-level asymmetry. The result of afb(lep) = 0.094 +0.032 -0.029 is to be compared to the standard model next-to-leading-order prediction of afb(lep) = 0.038 +-0.003.

We study charged particle production in proton-antiproton collisions at 300 GeV, 900 GeV, and 1.96 TeV. We use the direction of the charged particle with the largest transverse momentum in each event to define three regions of eta-phi space; toward, away, and transverse. The average number and the average scalar pT sum of charged particles in the transverse region are sensitive to the modeling of the underlying event. The transverse region is divided into a MAX and MIN transverse region, which helps separate the hard component (initial and final-state radiation) from the beam-beam remnant and multiple parton interaction components of the scattering. The center-of-mass energy dependence of the various components of the event are studied in detail. The data presented here can be used to constrain and improve QCD Monte Carlo models, resulting in more precise predictions at the LHC energies of 13 and 14 TeV.

Soft photons inside hadronic jets converted in front of the DELPHI main tracker (TPC) in events of qq̄ disintegrations of the Z0 were studied in the kinematic range 0.2<Eγ<1 GeV and transverse momentum with respect to the closest jet direction pT<80 MeV/c. A clear excess of photons in the experimental data as compared to the Monte Carlo predictions is observed. This excess (uncorrected for the photon detection efficiency) is (1.17±0.06±0.27)×10-3 γ/jet in the specified kinematic region, while the expected level of the inner hadronic bremsstrahlung (which is not included in the Monte Carlo) is (0.340±0.001±0.038)×10-3 γ/jet. The ratio of the excess to the predicted bremsstrahlung rate is then (3.4±0.2±0.8), which is similar in strength to the anomalous soft photon signal observed in fixed target experiments with hadronic beams.

A determination of the single W spin density matrix (SDM) elements in the reaction e+e-→W+W-→lνqq̄(l=e/μ) is reported at centre-of-mass energies between 189 and 209 GeV. The data sample used corresponds to an integrated luminosity of 520 pb-1 taken by DELPHI between 1998 and 2000. The single W SDM elements, ρττ' W± (τ,τ'=± 1 or 0), are determined as a function of the W- production angle with respect to the e- beam direction and are obtained from measurements of the W decay products by the application of suitable projection operators, Λττ', which assume the V-A coupling of the W-boson to fermions. The measured SDM elements are used to obtain the fraction of longitudinally polarised Ws, with the result: $\frac{\sigma_{\text{L}}}{\sigma_{{\text{tot}}}} = 24.9 \pm4.5({\text{stat}}) \pm2.2({\text{syst}})\%$ at a mean energy of 198 GeV. The SDM elements are also used to determine the triple gauge couplings Δg1 Z,Δκγ,λγ and g4 Z, $\tilde{\kappa}_{Z}$ and $\tilde{\lambda}_{Z}$ . For the CP-violating couplings the results of single parameter fits are: $g_4^{{Z}} = -0.39^{+0.19}_{-0.20}$ $\tilde{\kappa}_{{Z}} = -0.09^{+0.08}_{-0.05}$ $\tilde{\lambda}_{{Z}} = -0.08\pm0.07 .$ The errors are a combination of statistical and systematic errors. All results are consistent with the Standard Model.

Received 16 November 2011DOI:https://doi.org/10.1103/PhysRevLett.107.239903© 2011 American Physical Society

We present a search for a new narrow, spin-1, high mass resonance decaying to μ(+)μ⁻+X, using a matrix-element-based likelihood and a simultaneous measurement of the resonance mass and production rate. In data with 4.6 fb⁻¹ of integrated luminosity collected by the CDF detector in pp collisions at √s=1960 GeV, the most likely signal cross section is consistent with zero at 16% confidence level. We therefore do not observe evidence for a high mass resonance and place limits on models predicting spin-1 resonances, including M>1071 GeV/c² at 95% confidence level for a Z' boson with the same couplings to fermions as the Z boson.

An analysis of the direct soft photon production rate as a function of the parent jet characteristics is presented, based on hadronic events collected by the DELPHI experiment at LEP1. The dependences of the photon rates on the jet kinematic characteristics (momentum, mass, etc.) and on the jet charged, neutral and total hadron multiplicities are reported. Up to a scale factor of about four, which characterizes the overall value of the soft photon excess, a similarity of the observed soft photon behaviour to that of the inner hadronic bremsstrahlung predictions is found for the momentum, mass, and jet charged multiplicity dependences. However for the dependence of the soft photon rate on the jet neutral and total hadron multiplicities a prominent difference is found for the observed soft photon signal as compared to the expected bremsstrahlung from final state hadrons. The observed linear increase of the soft photon production rate with the jet total hadron multiplicity and its strong dependence on the jet neutral multiplicity suggest that the rate is proportional to the number of quark pairs produced in the fragmentation process, with the neutral pairs being more effectively radiating than the charged ones.

This article reports a measurement of the production cross section of prompt isolated photon pairs in proton-antiproton collisions at \sqrt{s} = 1.96 TeV using the CDF II detector at the Fermilab Tevatron collider. The data correspond to an integrated luminosity of 5.36/fb. The cross section is presented as a function of kinematic variables sensitive to the reaction mechanisms. The results are compared with three perturbative QCD calculations: (1) a leading order parton shower Monte Carlo, (2) a fixed next-to-leading order calculation and (3) a next-to-leading order/next-to-next-to-leading-log resummed calculation. The comparisons show that, within their known limitations, all calculations predict the main features of the data, but no calculation adequately describes all aspects of the data.

We measure the time dependence of the ratio of decay rates for ${D}^{0}\ensuremath{\rightarrow}{K}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ to the Cabibbo-favored decay ${D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$. The charge conjugate decays are included. A signal of $3.3\ifmmode\times\else\texttimes\fi{}{10}^{4}$ ${D}^{*+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{D}^{0}$, ${D}^{0}\ensuremath{\rightarrow}{K}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ decays is obtained with ${D}^{0}$ proper decay times between 0.75 and 10 mean ${D}^{0}$ lifetimes. The data were recorded with the CDF II detector at the Fermilab Tevatron and correspond to an integrated luminosity of $9.6\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ for $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$. Assuming $CP$ conservation, we search for ${D}^{0}$-${\overline{D}}^{0}$ mixing and measure the mixing parameters to be ${R}_{D}=(3.51\ifmmode\pm\else\textpm\fi{}0.35)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, ${y}^{\ensuremath{'}}=(4.3\ifmmode\pm\else\textpm\fi{}4.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, and ${x}^{\ensuremath{'}2}=(0.08\ifmmode\pm\else\textpm\fi{}0.18)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$. We report Bayesian probability intervals in the ${x}^{\ensuremath{'}2}$-${y}^{\ensuremath{'}}$ plane and find that the significance of excluding the no-mixing hypothesis is equivalent to 6.1 Gaussian standard deviations, providing the second observation of ${D}^{0}$-${\overline{D}}^{0}$ mixing from a single experiment.

We present a search for a new particle T' decaying to a top quark via T' -> t + X, where X goes undetected. We use a data sample corresponding to 5.7 fb-1 of integrated luminosity of ppbar collisions with sqrt{s} = 1.96 TeV, collected at Fermilab by the CDF II detector. Our search for pair production of T' is focused on the hadronic decay channel, ppbar -> T'T' -> tt +XX -> bbqqqq + XX. We interpret our results in terms of a model where T' is an exotic fourth generation quark and X is a dark matter candidate. The data are consistent with standard model expectations. We set a limit on the generic production of T'T'->tt+XX, excluding the fourth generation exotic quarks T' at 95% confidence level up to m_T' = 400 GeV/c2 for m_X < 70 GeV/c2.

We present a search for the pair production of a narrow nonstandard-model strongly interacting particle that decays to a pair of quarks or gluons, leading to a final state with four hadronic jets. We consider both nonresonant production via an intermediate gluon as well as resonant production via a distinct nonstandard-model intermediate strongly interacting particle. We use data collected by the CDF experiment in proton-antiproton collisions at √[s]=1.96 TeV corresponding to an integrated luminosity of 6.6 fb(-1). We find the data to be consistent with nonresonant production. We report limits on σ(pp[over ¯]→jjjj) as a function of the masses of the hypothetical intermediate particles. Upper limits on the production cross sections for nonstandard-model particles in several resonant and nonresonant processes are also derived.

We have observed exclusive γγ production in proton-antiproton collisions at √s=1.96 TeV, using data from 1.11±0.07 fb(-1) integrated luminosity taken by the Run II Collider Detector at Fermilab. We selected events with two electromagnetic showers, each with transverse energy E(T)>2.5 GeV and pseudorapidity |η|<1.0, with no other particles detected in -7.4<η<+7.4. The two showers have similar E(T) and azimuthal angle separation Δφ~π; 34 events have two charged particle tracks, consistent with the QED process pp¯→p+e(+)e(-)+p¯ by two-photon exchange, while 43 events have no charged tracks. The number of these events that are exclusive π(0)π(0) is consistent with zero and is <15 at 95% C.L. The cross section for pp¯→p+γγ+p¯ with |η(γ)|<1.0 and E(T)(γ)>2.5 GeV is 2.48(-0.35)(+0.40)(stat)(-0.51)(+0.40)(syst) pb.

We present the first measurement of polarization and CP-violating asymmetries in a B(s)(0) decay into two light vector mesons, B(s)(0)→φφ, and an improved determination of its branching ratio using 295 decays reconstructed in a data sample corresponding to 2.9 fb(-1) of integrated luminosity collected by the CDF experiment at the Fermilab Tevatron collider. The fraction of longitudinal polarization is determined to be f(L)=0.348±0.041(stat)±0.021(syst), and the branching ratio B(B(s)(0)→φφ)=[2.32±0.18(stat)±0.82(syst)]×10(-5). Asymmetries of decay angle distributions sensitive to CP violation are measured to be A(u)=-0.007±0.064(stat)±0.018(syst) and A(v)=-0.120±0.064(stat)±0.016(syst).

We present a search for a new particle T′ decaying to top quark via T′→t+X, where X is an invisible particle. In a data sample with 4.8 fb−1 of integrated luminosity collected by the CDF II detector at Fermilab in p¯p collisions with √s=1.96 TeV, we search for pair production of T′ in the lepton+jets channel, p¯p→t¯t+X+X→ℓνbqq′b+X+X. We interpret our results primarily in terms of a model where T′ are exotic fourth generation quarks and X are dark matter particles. Current direct and indirect bounds on such exotic quarks restrict their masses to be between 300 and 600 GeV/c2, the dark matter particle mass being anywhere below mT′. The data are consistent with standard model expectations, and we set 95% confidence level limits on the generic production of T′¯¯¯T′→t¯t+X+X. For the dark matter model we exclude T′ at 95% confidence level up to mT′=360 GeV/c2 for mX≤100 GeV/c2.Received 12 March 2011DOI:https://doi.org/10.1103/PhysRevLett.106.191801© 2011 American Physical Society

We combine the results of searches for the standard model Higgs boson based on the full CDF Run II data set obtained from sqrt(s) = 1.96 TeV p-pbar collisions at the Fermilab Tevatron corresponding to an integrated luminosity of 9.45/fb. The searches are conducted for Higgs bosons that are produced in association with a W or Z boson, have masses in the range 90-150 GeV/c^2, and decay into bb pairs. An excess of data is present that is inconsistent with the background prediction at the level of 2.5 standard deviations (the most significant local excess is 2.7 standard deviations).

We present a search for the standard model Higgs boson produced in association with a $W$ boson in $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ $p\overline{p}$ collision data collected with the CDF II detector at the Tevatron corresponding to an integrated luminosity of $9.45\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. In events consistent with the decay of the Higgs boson to a bottom-quark pair and the $W$ boson to an electron or muon and a neutrino, we set 95% credibility level upper limits on the $WH$ production cross section times the $H\ensuremath{\rightarrow}b\overline{b}$ branching ratio as a function of Higgs boson mass. At a Higgs boson mass of $125\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, we observe (expect) a limit of 4.9 (2.8) times the standard model value.

This Letter reports a search for a narrow resonant state decaying into two W bosons and two b quarks where one W boson decays leptonically and the other decays into a quark-antiquark pair. The search is particularly sensitive to top-antitop resonant production. We use the full data sample of proton-antiproton collisions at a center-of-mass energy of 1.96 TeV collected by the CDF II detector at the Fermilab Tevatron, corresponding to an integrated luminosity of 9.45 fb(-1). No evidence for resonant production is found, and upper limits on the production cross section times branching ratio for a narrow resonant state are extracted. Within a specific benchmark model, we exclude a Z' boson with mass, M(Z'), below 915 GeV/c(2) decaying into a top-antitop pair at the 95% credibility level assuming a Z' boson decay width of Γ(Z') = 0.012 M(Z'). This is the most sensitive search for a narrow qq-initiated tt resonance in the mass region below 750 GeV/c(2).

This Letter describes the current most precise measurement of the $WZ$ production cross section as well as limits on anomalous $WWZ$ couplings at a center-of-mass energy of 1.96 TeV in proton-antiproton collisions for the Collider Detector at Fermilab (CDF). $WZ$ candidates are reconstructed from decays containing three charged leptons and missing energy from a neutrino, where the charged leptons are either electrons or muons. Using data collected by the CDF II detector (7.1 fb$^{-1}$ of integrated luminosity), 63 candidate events are observed with the expected background contributing $8 \pm 1$ events. The measured total cross section $\sigma (p \bar p \to WZ) = 3.93_{-0.53}^{+0.60}(\text{stat})_{-0.46}^{+0.59}(\text{syst}) $ pb is in good agreement with the standard model prediction of $3.50\pm 0.21$. The same sample is used to set limits on anomalous $WWZ$ couplings.

Using data corresponding to $6.0\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ collected by the CDF II detector, we present a cross section measurement of top-quark pair production with an additional radiated photon in the central region with 10 GeV or more of transverse energy $t\overline{t}\ensuremath{\gamma}$. The events are selected by looking for a lepton ($\ensuremath{\ell}$ or $\ensuremath{\mu}$), a photon ($\ensuremath{\gamma}$), significant transverse momentum imbalance (${\mathrm{E\ensuremath{\llap{\not\;}}}}_{T}$), large total transverse energy, and three or more jets, with at least one identified as containing a $b$ quark ($b$). Using an event selection optimized for the $t\overline{t}\ensuremath{\gamma}$ candidate sample, we also measure the cross section of $t\overline{t}$ (${\ensuremath{\sigma}}_{t\overline{t}}$). We measure the $t\overline{t}\ensuremath{\gamma}$ cross section (${\ensuremath{\sigma}}_{t\overline{t}\ensuremath{\gamma}}$) to be $0.18\ifmmode\pm\else\textpm\fi{}0.08\text{ }\text{ }\mathrm{pb}$, and the ratio of ${\ensuremath{\sigma}}_{t\overline{t}\ensuremath{\gamma}}$ to ${\ensuremath{\sigma}}_{t\overline{t}}$ to be $0.024\ifmmode\pm\else\textpm\fi{}0.009$. We observe a probability of 0.0015 (3.0 standard deviations) of the background (non-$t\overline{t}\ensuremath{\gamma}$ events alone producing 30 events or more.

The observation of the bottom, strange baryon Ξ(b)(0) through the decay chain Ξ(b)(0)→Ξ(c)(+)π-, where ΞΞ(c)(+)→Ξ- π+ π+, Ξ-→Λπ-, and Λ→pπ-, is reported by using data corresponding to an integrated luminosity of 4.2 fb(-1) from pp collisions at square root(s)=1.96 TeV recorded with the Collider Detector at Fermilab. A signal of 25.3(-5.4)(+5.6) candidates is observed whose probability of arising from a background fluctuation is 3.6×10(-12), corresponding to 6.8 gaussian standard deviations. The Ξ(b)(0) mass is measured to be 5787.8±5.0(stat)±1.3(syst) MeV/c2. In addition, the Ξ(b)- baryon is observed through the process Ξ(b)-→Ξ(c)(0)π-, where Ξ(c)(0)→Ξ- π+, Ξ-→Λπ-, and Λ→pπ-.

We report on mass and lifetime measurements of several ground state charmed and bottom baryons, using a data sample corresponding to $9.6\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ from $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ and recorded with the Collider Detector at Fermilab. Baryon candidates are reconstructed from data collected with an online event selection designed for the collection of long-lifetime heavy-flavor decay products and a second event selection designed to collect $J/\ensuremath{\psi}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ candidates. First evidence for the process ${\mathrm{\ensuremath{\Omega}}}_{b}^{\ensuremath{-}}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Omega}}}_{c}^{0}{\ensuremath{\pi}}^{\ensuremath{-}}$ is presented with a significance of $3.3\ensuremath{\sigma}$. We measure the following baryon masses: $M({\mathrm{\ensuremath{\Xi}}}_{c}^{0})=2470.85\ifmmode\pm\else\textpm\fi{}0.24(\text{stat})\ifmmode\pm\else\textpm\fi{}0.55(\text{syst})\text{ }\text{ }\mathrm{MeV}/{c}^{2},\phantom{\rule{0ex}{0ex}}M({\mathrm{\ensuremath{\Xi}}}_{c}^{+})=2468.00\ifmmode\pm\else\textpm\fi{}0.18(\text{stat})\ifmmode\pm\else\textpm\fi{}0.51(\text{syst})\text{ }\text{ }\mathrm{MeV}/{c}^{2},\phantom{\rule{0ex}{0ex}}M({\mathrm{\ensuremath{\Lambda}}}_{b})=5620.15\ifmmode\pm\else\textpm\fi{}0.31(\text{stat})\ifmmode\pm\else\textpm\fi{}0.47(\text{syst})\text{ }\text{ }\mathrm{MeV}/{c}^{2},\phantom{\rule{0ex}{0ex}}M({\mathrm{\ensuremath{\Xi}}}_{b}^{\ensuremath{-}})=5793.4\ifmmode\pm\else\textpm\fi{}1.8(\text{stat})\ifmmode\pm\else\textpm\fi{}0.7(\text{syst})\text{ }\text{ }\mathrm{MeV}/{c}^{2},\phantom{\rule{0ex}{0ex}}M({\mathrm{\ensuremath{\Xi}}}_{b}^{0})=5788.7\ifmmode\pm\else\textpm\fi{}4.3(\text{stat})\ifmmode\pm\else\textpm\fi{}1.4(\text{syst})\text{ }\text{ }\mathrm{MeV}/{c}^{2},\phantom{\rule[-0.0ex]{1em}{0.0ex}}\text{and}\phantom{\rule{0ex}{0ex}}M({\mathrm{\ensuremath{\Omega}}}_{b}^{\ensuremath{-}})=6047.5\ifmmode\pm\else\textpm\fi{}3.8(\text{stat})\ifmmode\pm\else\textpm\fi{}0.6(\text{syst})\text{ }\text{ }\mathrm{MeV}/{c}^{2}.$The isospin splitting of the ${\mathrm{\ensuremath{\Xi}}}_{b}^{\ensuremath{-},0}$ states is found to be $M({\mathrm{\ensuremath{\Xi}}}_{b}^{\ensuremath{-}})\ensuremath{-}M({\mathrm{\ensuremath{\Xi}}}_{b}^{0})=4.7\ifmmode\pm\else\textpm\fi{}4.7(\text{stat})\ifmmode\pm\else\textpm\fi{}0.7(\text{syst})\text{ }\mathrm{MeV}/{c}^{2}$. The isospin splitting of the ${\mathrm{\ensuremath{\Xi}}}_{c}^{0,+}$ states is found to be $M({\mathrm{\ensuremath{\Xi}}}_{c}^{0})\ensuremath{-}M({\mathrm{\ensuremath{\Xi}}}_{c}^{+})=2.85\ifmmode\pm\else\textpm\fi{}0.30(\text{stat})\ifmmode\pm\else\textpm\fi{}\phantom{\rule{0ex}{0ex}}0.04(\text{syst})\text{ }\mathrm{MeV}/{c}^{2}$. The following lifetime measurements are made: $\ensuremath{\tau}({\mathrm{\ensuremath{\Lambda}}}_{b})=1.565\ifmmode\pm\else\textpm\fi{}0.035(\text{stat})\ifmmode\pm\else\textpm\fi{}0.020(\text{syst})\text{ }\text{ }\mathrm{ps},\phantom{\rule{0ex}{0ex}}\ensuremath{\tau}({\mathrm{\ensuremath{\Xi}}}_{b}^{\ensuremath{-}})=1.32\ifmmode\pm\else\textpm\fi{}0.14(\text{stat})\ifmmode\pm\else\textpm\fi{}0.02(\text{syst})\text{ }\text{ }\mathrm{ps},\phantom{\rule{0ex}{0ex}}\ensuremath{\tau}({\mathrm{\ensuremath{\Omega}}}_{b}^{\ensuremath{-}})=1.6{6}_{\ensuremath{-}0.40}^{+0.53}(\text{stat})\ifmmode\pm\else\textpm\fi{}0.02(\text{syst})\text{ }\text{ }\mathrm{ps}.$

The first observation of the production of a W boson with a single charm quark (c) jet in pp[over ¯] collisions at √s=1.96 TeV is reported. The analysis uses data corresponding to 4.3 fb(-1), recorded with the CDF II detector at the Fermilab Tevatron. Charm quark candidates are selected through the identification of an electron or muon from charm-hadron semileptonic decay within a hadronic jet, and a Wc signal is observed with a significance of 5.7 standard deviations. The production cross section σ(Wc)(p(Tc)>20 GeV/c,|η(c)|<1.5)×B(W→ℓν) is measured to be 13.6(-3.1)(+3.4) pb and is in agreement with theoretical expectations. From this result the magnitude of the quark-mixing matrix element V(cs) is derived, |V(cs)|=1.08±0.16 along with a lower limit of |V(cs)|>0.71 at the 95% confidence level, assuming that the Wc production through c to s quark coupling is dominant.

We measure exclusive $\pi^+\pi^-$ production in proton-antiproton collisions at center-of-mass energies $\sqrt{s}$ = 0.9 and 1.96 TeV in the Collider Detector at Fermilab. We select events with two oppositely charged particles, assumed to be pions, with pseudorapidity $|\eta| < 1.3$ and with no other particles detected in $|\eta| < 5.9$. We require the $\pi^+\pi^-$ system to have rapidity $|y|<$ 1.0. The production mechanism of these events is expected to be dominated by double pomeron exchange, which constrains the quantum numbers of the central state. The data are potentially valuable for isoscalar meson spectroscopy and for understanding the pomeron in a region of transition between nonperturbative and perturbative quantum chromodynamics. The data extend up to dipion mass $M(\pi^+\pi^-)$ = 5000 MeV/$c^2$ and show resonance structures attributed to $f_0$ and $f_2(1270)$ mesons. From the $\pi^+\pi^-$ and $K^+K^-$ spectra, we place upper limits on exclusive $\chi_{c0}(3415)$ production.

This document summarises the talks and discussions happened during the VBSCan Split17 workshop, the first general meeting of the VBSCan COST Action network. This collaboration is aiming at a consistent and coordinated study of vector-boson scattering from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

A search for single top production (e+e−→tc̄) via flavour changing neutral currents (FCNC) was performed using the data taken by the DELPHI detector at LEP2. The data analyzed have been accumulated at center-of-mass energies ranging from 189 to 208 GeV. Limits at 95% confidence level were obtained on the anomalous coupling parameters κγ and κZ.

This paper presents DELPHI measurements and interpretations of cross-sections, forward-backward asymmetries, and angular distributions, for the e+e- -&gt; ffbar process for centre-of-mass energies above the Z resonance, from sqrt(s) ~ 130 - 207 GeV at the LEP collider. The measurements are consistent with the predictions of the Standard Model and are used to study a variety of models including the S-Matrix ansatz for e+e- -&gt; ffbar scattering and several models which include physics beyond the Standard Model: the exchange of Z' bosons, contact interactions between fermions, the exchange of gravitons in large extra dimensions and the exchange of sneutrino in R-parity violating supersymmetry.

We present a direct measurement of the mass difference between t and ¯t quarks using t¯t candidate events in the lepton+jets channel, collected with the CDF II detector at Fermilab’s 1.96 TeV Tevatron p¯p Collider. We make an event by event estimate of the mass difference to construct templates for top quark pair signal events and background events. The resulting mass difference distribution of data is compared to templates of signals and background using a maximum likelihood fit. From a sample corresponding to an integrated luminosity of 5.6 fb−1, we measure a mass difference, ΔMtop=Mt−M¯t=−3.3±1.4(stat)±1.0(syst) GeV/c2, approximately 2 standard deviations away from the CPT hypothesis of zero mass difference.Received 14 March 2011DOI:https://doi.org/10.1103/PhysRevLett.106.152001© 2011 American Physical Society

We present a measurement of the top quark mass in the $\mathrm{\text{lepton}}+\mathrm{\text{jets}}$ and dilepton channels of $t\overline{t}$ decays using the data sample corresponding to an integrated luminosity of $5.6\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of $p\overline{p}$ collisions at Tevatron with $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$, collected with the CDF II detector. We construct templates of two reconstructed top quark masses from different jets-to-quarks combinations and the invariant mass of two jets from the $W$ decays in the $\mathrm{\text{lepton}}+\mathrm{\text{jets}}$ channel, and a reconstructed top quark mass and ${m}_{T2}$, a variable related to the transverse mass in events with two missing particles, in the dilepton channel. The simultaneous fit of the templates from signal and background events in the $\mathrm{\text{lepton}}+\mathrm{\text{jets}}$ and dilepton channels to the data yields a measured top quark mass of ${\mathrm{M}}_{\mathrm{top}}=172.1\ifmmode\pm\else\textpm\fi{}1.1(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.9(\mathrm{syst})\text{ }\text{ }\mathrm{GeV}/{c}^{2}$.

Using \Zg\ candidate events collected by the CDF detector at the Tevatron Colli\der, we search for potential anomalous (non-standard-model) couplings between t\he $Z$ boson and the photon. \Zg\ couplings vanish at tree level and are heavil\y suppressed at higher orders; hence any evidence of couplings indicates new ph\ysics. Measurements are performed using data corresponding to an integrated lum\inosity of 4.9 \invfb\ in the $Z \rightarrow \nu\bar{\nu}$ decay channel and 5.\1 \invfb\ in the \Zll\ ($l=\mu, e$) decay channels. The combination of these me\asurements provides the most stringent limits to date on \Zg\ trilinear gauge c\ouplings. Using an energy scale of $\Lambda = 1.5$\ TeV to allow for a direct c\omparison with previous measurements, we find limits on the CP-conserving param\eters that describe \Zg\ couplings to be $|h_3^{\gamma,Z}| < 0.022 $ and $|h_4^\{\gamma,Z}| < 0.0009$. These results are consistent with standard model predict\ions.

We present a search for the standard model Higgs boson produced in association with a Z boson in data collected with the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.45/fb. In events consistent with the decay of the Higgs boson to a bottom-quark pair and the Z boson to electron or muon pairs, we set 95% credibility level upper limits on the ZH production cross section times the H -> bb branching ratio as a function of Higgs boson mass. At a Higgs boson mass of 125 GeV/c^2 we observe (expect) a limit of 7.1 (3.9) times the standard model value.

Drell-Yan lepton pairs are produced in the process $p\overline{p}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}+X$ through an intermediate ${\ensuremath{\gamma}}^{*}/Z$ boson. The lepton angular distributions are used to provide information on the electroweak-mixing parameter ${sin}^{2}{\ensuremath{\theta}}_{W}$ via its observable effective-leptonic ${sin}^{2}{\ensuremath{\theta}}_{W}$, or ${sin}^{2}{\ensuremath{\theta}}_{\mathrm{eff}}^{\mathrm{lept}}$. A new method to infer ${sin}^{2}{\ensuremath{\theta}}_{W}$ or, equivalently, the $W$-boson mass ${M}_{W}$ in the on-shell scheme, is developed and tested using a previous CDF Run II measurement of angular distributions from electron pairs in a sample corresponding to $2.1\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity from $p\overline{p}$ collisions at a center-of-momentum energy of 1.96 TeV. The value of ${sin}^{2}{\ensuremath{\theta}}_{\mathrm{eff}}^{\mathrm{lept}}$ is found to be $0.2328\ifmmode\pm\else\textpm\fi{}0.0011$. Within a specified context of the standard model, this results in ${sin}^{2}{\ensuremath{\theta}}_{W}=0.2246\ifmmode\pm\else\textpm\fi{}0.0011$, which corresponds to a $W$-boson mass of $80.297\ifmmode\pm\else\textpm\fi{}0.055\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, in agreement with previous determinations in electron-position collisions and at the Tevatron collider.

A search for new dielectron-mass resonances using data recorded by the CDF II detector and corresponding to an integrated luminosity of 5.7 fb(-1) is presented. No significant excess over the expected standard model prediction is observed. In this data set, an event with the highest dielectron mass ever observed (960 GeV/c(2)) was recorded. The results are interpreted in the Randall-Sundrum (RS) model. Combined with the 5.4 fb(-1) diphoton analysis, the RS-graviton lower-mass limit for the coupling k/M¯(Pl)=0.1 is 1058 GeV/c(2), making it the strongest limit to date.

Using data from $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ recorded by the CDF II detector at the Fermilab Tevatron, we present improved measurements of the masses and first measurements of natural widths of the four bottom baryon resonance states ${\ensuremath{\Sigma}}_{b}^{+}$, ${\ensuremath{\Sigma}}_{b}^{*+}$ and ${\ensuremath{\Sigma}}_{b}^{\ensuremath{-}}$, ${\ensuremath{\Sigma}}_{b}^{*\ensuremath{-}}$. These states are fully reconstructed in their decay modes to ${\ensuremath{\Lambda}}_{b}^{0}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$ where ${\ensuremath{\Lambda}}_{b}^{0}\ensuremath{\rightarrow}{\ensuremath{\Lambda}}_{c}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ with ${\ensuremath{\Lambda}}_{c}^{+}\ensuremath{\rightarrow}p{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$. The analysis is based on a data sample corresponding to an integrated luminosity of $6.0\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected by an online event selection based on tracks displaced from the $p\overline{p}$ interaction point.

We report a measurement of the differential cross section $d\ensuremath{\sigma}/d(\mathrm{cos}{\ensuremath{\theta}}_{t})$ for top-quark pair production as a function of the top-quark production angle in proton-antiproton collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$. This measurement is performed using data collected with the CDF II detector at the Tevatron, corresponding to an integrated luminosity of $9.4\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. We employ the Legendre polynomials to characterize the shape of the differential cross section at the parton level. The observed Legendre coefficients are in good agreement with the prediction of the next-to-leading-order standard-model calculation, with the exception of an excess linear-term coefficient ${a}_{1}=0.40\ifmmode\pm\else\textpm\fi{}0.12$, compared to the standard-model prediction of ${a}_{1}={0.15}_{\ensuremath{-}0.03}^{+0.07}$.

We present a measurement of the $W$-boson mass, $M_W$, using data corresponding to 2.2/fb of integrated luminosity collected in ppbar collisions at $\sqrt{s}$ = 1.96 TeV with the CDF II detector at the Fermilab Tevatron. The selected sample of 470126 $W\to e\nu$ candidates and 624708 $W\to\mu\nu$ candidates yields the measurement $M_W = 80387\pm 12$ (stat) $\pm 15$ (syst)$ = 80387 \pm 19$ MeV$/c^2$ . This is the most precise single measurement of the $W$-boson mass to date.

We report on a measurement of the cross section for direct-photon production in association with a heavy quark using the full data set of sqrt[s]=1.96 TeV proton-antiproton collisions corresponding to 9.1 fb-1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron. The measurements are performed as a function of the photon transverse momentum, covering a photon transverse momentum between 30 and 300 GeV, photon rapidities |yγ|<1.0, a heavy-quark-jet transverse momentum pTjet>20 GeV, and jet rapidities |yjet|<1.5. The results are compared with several theoretical predictions.

Differential cross sections for the production of $Z$ bosons or off-shell photons $\gamma^*$ in association with jets are measured in proton-antiproton collisions at center-of-mass energy $\sqrt{s}=1.96$ TeV using the full data set collected with the Collider Detector at Fermilab in Tevatron Run II, and corresponding to 9.6 fb$^{-1}$ of integrated luminosity. Results include first measurements at CDF of differential cross sections in events with a $Z/\gamma^*$ boson and three or more jets, the inclusive cross section for production of $Z/\gamma^*$ and four or more jets, and cross sections as functions of various angular observables in lower jet-multiplicity final states. Measured cross sections are compared to several theoretical predictions.

We report evidence for s-channel single-top-quark production in proton-antiproton collisions at center-of-mass energy sqrt[s] = 1.96 TeV using a data set that corresponds to an integrated luminosity of 9.4 fb(-1) collected by the Collider Detector at Fermilab. We select events consistent with the s-channel process including two jets and one leptonically decaying W boson. The observed significance is 3.8 standard deviations with respect to the background-only prediction. Assuming a top-quark mass of 172.5 GeV/c(2), we measure the s-channel cross section to be 1.41(-0.42)(+0.44) pb.

Drell-Yan lepton pairs are produced in the process $p\bar{p} \rightarrow \mu^+\mu^- + X$ through an intermediate $\gamma^*/Z$ boson. The forward-backward asymmetry in the polar-angle distribution of the $\mu^-$ as a function of the invariant mass of the $\mu^+\mu^-$ pair is used to obtain the effective leptonic determination $\sin^2 \theta^{lept}_{eff}$ of the electroweak-mixing parameter $\sin^2 \theta_W$, from which the value of $\sin^2 \theta_W$ is derived assuming the standard model. The measurement sample, recorded by the Collider Detector at Fermilab (CDF), corresponds to 9.2 fb-1 of integrated luminosity from $p\bar{p}$ collisions at a center-of-momentum energy of 1.96 TeV, and is the full CDF Run II data set. The value of $\sin^2 \theta^{lept}_{eff}$ is found to be 0.2315 +- 0.0010, where statistical and systematic uncertainties are combined in quadrature. When interpreted within the context of the standard model using the on-shell renormalization scheme, where $\sin^2 \theta_W = 1 - M_W^2/M_Z^2$, the measurement yields $\sin^2 \theta_W$ = 0.2233 +- 0.0009, or equivalently a W-boson mass of 80.365 +- 0.047 GeV/c^2. The value of the W-boson mass is in agreement with previous determinations in electron-positron collisions and at the Tevatron collider.

Inclusive J/psi production in photon-photon collisions has been observed at LEP II beam energies. A clear signal from the reaction gamma gamma -&gt; J/psi+X is seen. The number of observed N(J/psi -&gt; mu+mu-) events is 36 +/- 7 for an integrated luminosity of 617 pb^{-1}, yielding a cross-section of sigma(J/psi+X) = 45 +/- 9 (stat) +/- 17 (syst) pb. Based on a study of the event shapes of different types of gamma gamma processes in the PYTHIA program, we conclude that (74 +/- 22)% of the observed J/psi events are due to `resolved' photons, the dominant contribution of which is most probably due to the gluon content of the photon.

We present a search for a new heavy charged vector boson ${W}^{\ensuremath{'}}$ decaying to an electron-neutrino pair in $p\overline{p}$ collisions at a center-of-mass energy of 1.96 TeV. The data were collected with the CDF II detector and correspond to an integrated luminosity of $5.3\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. No significant excess above the standard model expectation is observed and we set upper limits on $\ensuremath{\sigma}\ifmmode\cdot\else\textperiodcentered\fi{}\mathcal{B}({W}^{\ensuremath{'}}\ensuremath{\rightarrow}e\ensuremath{\nu})$. Assuming standard model couplings to fermions and the neutrino from the ${W}^{\ensuremath{'}}$ boson decay to be light, we exclude a ${W}^{\ensuremath{'}}$ boson with mass less than $1.12\text{ }\text{ }\mathrm{TeV}/{c}^{2}$ at the 95% confidence level.

We report the first observation of two Cabibbo-suppressed decay modes of the ${B}_{s}^{0}$ meson. Using a sample of $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ corresponding to $5.9\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity collected with the CDF II, the collider detector at the Fermilab Tevatron, we search for new ${B}_{s}^{0}$ decay modes in a sample of events containing $J/\ensuremath{\psi}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ decays. We reconstruct a ${B}_{s}^{0}\ensuremath{\rightarrow}J/\ensuremath{\psi}{K}^{*}(892{)}^{0}$ signal with ${K}^{*}(892{)}^{0}\ensuremath{\rightarrow}{K}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$, observing a yield of $151\ifmmode\pm\else\textpm\fi{}25$ events with a statistical significance of $8.0\ensuremath{\sigma}$. We also reconstruct a ${B}_{s}^{0}\ensuremath{\rightarrow}J/\ensuremath{\psi}{K}_{S}^{0}$ signal with ${K}_{S}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$, observing a yield of $64\ifmmode\pm\else\textpm\fi{}14$ events with a statistical significance of $7.2\ensuremath{\sigma}$. From these yields, we extract the branching ratios $\mathcal{B}({B}_{s}^{0}\ensuremath{\rightarrow}J/\ensuremath{\psi}{K}^{*}(892{)}^{0})=(8.3\ifmmode\pm\else\textpm\fi{}3.8)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ and $\mathcal{B}({B}_{s}^{0}\ensuremath{\rightarrow}J/\ensuremath{\psi}{K}^{0})=(3.5\ifmmode\pm\else\textpm\fi{}0.8)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, where statistical, systematic, and fragmentation-fraction uncertainties are included in the combined uncertainty.

In this Letter, we present a precise measurement of the total ZZ production cross section in pp collisions at sqrt[s]=1.96 TeV, using data collected with the CDF II detector corresponding to an integrated luminosity of approximately 6 fb(-1). The result is obtained by combining separate measurements in the four-charged (ℓℓℓ' ℓ') and two-charged-lepton and two-neutral-lepton (ℓℓνν) decay modes of the Z boson pair. The combined measured cross section for pp → ZZ is 1.64(-0.38)(+0.44) pb. This is the most precise measurement of the ZZ production cross section in 1.96 TeV pp collisions to date.

We present a search for new physics in events with two high $p_T$ leptons of the same electric charge, using data with an integrated luminosity of 6.1 fb$^{-1}$. The observed data are consistent with standard model predictions. We set 95% C.L. lower limits on the mass of doubly-charged scalars decaying to like-sign dileptons, $m_{H^{\pm\pm}}> 190-245$ GeV/$c^2$, depending on the decay mode and coupling.

We report on a search for \bsmm\ and \bdmm\ decays using proton-antiproton collision data at $\sqrt{s}=1.96$ TeV corresponding to $10 \fb$ of integrated luminosity collected by the CDF detector at the Fermilab Tevatron collider. The observed number of \bd\ candidates is consistent with background-only expectations and yields an upper limit on the branching fraction of $\brbdmm < 4.6\times 10^{-9}$ at 95% confidence level. We observe an excess of \bs\ candidates. The probability that the background processes alone could produce such an excess or larger is 0.94%. The probability that the combination of background and the expected standard model rate of \bsmm\ could produce such an excess or larger is 6.8%. These data are used to determine a branching fraction $\brbsmm = (1.3^{+0.9}_{-0.7}) \times 10^{-8} $ and provide an upper limit of $\brbsmm < 3.1\times 10^{-8}$ at 95% confidence level.

We search for resonant production of tt pairs in 4.8 fb^{-1} integrated luminosity of ppbar collision data at sqrt{s}=1.96 TeV in the lepton+jets decay channel, where one top quark decays leptonically and the other hadronically. A matrix element reconstruction technique is used; for each event a probability density function (pdf) of the ttbar candidate invariant mass is sampled. These pdfs are used to construct a likelihood function, whereby the cross section for resonant ttbar production is estimated, given a hypothetical resonance mass and width. The data indicate no evidence of resonant production of ttbar pairs. A benchmark model of leptophobic Z \rightarrow ttbar is excluded with m_{Z'} < 900 GeV at 95% confidence level.

We report on a search for new particles in the diphoton channel using a data sample of $p\bar p$ collisions at $\sqrt{s} = 1.96$ TeV collected by the CDF II detector at the Fermilab Tevatron, with an integrated luminosity of 5.4 fb$^{-1}$. The diphoton invariant mass spectrum of the data agrees well with the standard model expectation. We set upper limits on the production cross section times branching ratio for the Randall-Sundrum graviton, as a function of diphoton mass. We subsequently derive lower limits on the graviton mass of 459 GeV$/c^{2}$ and 963 GeV$/c^{2}$, at the 95% confidence level, for coupling parameters ($k/\bar{M}_{Pl}$) of 0.01 and 0.1 respectively.

We measure the polarization of $W$ bosons from top-quark ($t$) decays into final states with a charged lepton and jets, $t\overline{t}\ensuremath{\rightarrow}{W}^{+}b{W}^{\ensuremath{-}}\overline{b}\ensuremath{\rightarrow}\ensuremath{\ell}\ensuremath{\nu}bq{\overline{q}}^{\ensuremath{'}}\overline{b}$, using the full Run II data set collected by the CDF II detector, corresponding to an integrated luminosity of $8.7\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. A model-independent method simultaneously determines the fraction of longitudinal (${f}_{0}$) and right-handed (${f}_{+}$) $W$ bosons to yield ${f}_{0}=0.726\ifmmode\pm\else\textpm\fi{}0.066(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.067(\mathrm{syst})$ and ${f}_{+}=\ensuremath{-}0.045\ifmmode\pm\else\textpm\fi{}0.044(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.058(\mathrm{syst})$ with a correlation coefficient of $\ensuremath{-}0.69$. Additional results are presented under various standard model assumptions. No significant discrepancies with the standard model are observed.

We report on a measurement of the top-quark electric charge in $t\overline{t}$ events in which one $W$ boson originating from the top-quark pair decays into leptons and the other into hadrons. The event sample was collected by the CDF II detector in $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ proton-antiproton collisions and corresponds to $5.6\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. We find the data to be consistent with the standard model and exclude the existence of an exotic quark with $\ensuremath{-}4/3$ electric charge and mass of the conventional top quark at the 99% confidence level.

We report a measurement of the indirect $CP$-violating asymmetries (${A}_{\mathrm{\ensuremath{\Gamma}}}$) between effective lifetimes of anticharm and charm mesons reconstructed in ${D}^{0}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}$ and ${D}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ decays. We use the full data set of proton-antiproton collisions collected by the Collider Detector at Fermilab experiment and corresponding to $9.7\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity. The strong-interaction decay ${D}^{*+}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{+}$ is used to identify the meson at production as ${D}^{0}$ or ${\overline{D}}^{0}$. We statistically subtract ${D}^{0}$ and ${\overline{D}}^{0}$ mesons originating from $b$-hadron decays and measure the yield asymmetry between anticharm and charm decays as a function of decay time. We measure ${A}_{\mathrm{\ensuremath{\Gamma}}}({K}^{+}{K}^{\ensuremath{-}})=(\ensuremath{-}0.19\ifmmode\pm\else\textpm\fi{}0.15(\text{stat})\ifmmode\pm\else\textpm\fi{}0.04(\text{syst}))%$ and ${A}_{\mathrm{\ensuremath{\Gamma}}}({\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})=\phantom{\rule{0ex}{0ex}}(\ensuremath{-}0.01\ifmmode\pm\else\textpm\fi{}0.18(\text{stat})\ifmmode\pm\else\textpm\fi{}0.03(\text{syst}))%$. The results are consistent with the hypothesis of $CP$ symmetry and their combination yields ${A}_{\mathrm{\ensuremath{\Gamma}}}=(\ensuremath{-}0.12\ifmmode\pm\else\textpm\fi{}0.12)%$.

We report on a study of diffractive dijet production in $\bar{p}p$ collisions at $\sqrt{s}=1.96$ TeV using the CDF II detector at the Fermilab Tevatron $\bar{p}p$ collider. A data sample from 310 pb$^{-1}$ of integrated luminosity collected by triggering on a high transverse energy jet, $E_T^{jet}$, in coincidence with a recoil antiproton detected in a Roman pot spectrometer is used to measure the ratio of single-diffractive to inclusive-dijet event rates as a function of $x^{\bar p}$ of the interacting parton in the antiproton, the Bjorken-$x$, $x^{\bar p}_{Bj}$, and a $Q^2\approx (E_T^{jet})^2$ in the ranges $10^{-3}<x^{\bar p}_{Bj}<10^{-1}$ and $10^2<Q^2 <10^4$ GeV$^2$, respectively. Results are presented for the region of $\bar p$-momentum-loss fraction $0.03<\xi_{\bar p}<0.09$ and a four-momentum transfer squared $t_{\bar p}>-4$ GeV$^2$. The $t_{\bar p}$ dependence is measured as a function of $Q^2$ and $x_{Bj}^{\bar p}$ and compared with that of inclusive single diffraction dissociation. We find weak $x^{\bar p}_{Bj}$ and $Q^2$ dependencies in the ratio of single diffractive to inclusive event rates, and no significant $Q^2$ dependence in the diffractive $t_{\bar p}$ distributions.

We present a combination of searches for the standard model Higgs boson using the full CDF run II data set, which corresponds to an integrated luminosity of $9.45--10.0\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected from $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ $p\overline{p}$ collisions at the Fermilab Tevatron. The searches consider Higgs boson production from gluon-gluon fusion, vector-boson fusion, and associated production with either a $W$ or $Z$ boson or a $t\overline{t}$ pair. Depending on the production mode, Higgs boson decays to ${W}^{+}{W}^{\ensuremath{-}}$, $ZZ$, $b\overline{b}$, ${\ensuremath{\tau}}^{+}{\ensuremath{\tau}}^{\ensuremath{-}}$, and $\ensuremath{\gamma}\ensuremath{\gamma}$ are examined. We search for a Higgs boson with masses (${m}_{H}$) in the range $90--200\text{ }\text{ }\mathrm{GeV}/{c}^{2}$. In the absence of a signal, we expect based on combined search sensitivity to exclude at the 95% credibility level the mass regions $90&lt;{m}_{H}&lt;94\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, $96&lt;{m}_{H}&lt;106\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, and $153&lt;{m}_{H}&lt;175\text{ }\text{ }\mathrm{GeV}/{c}^{2}$. The observed exclusion regions are $90&lt;{m}_{H}&lt;102\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ and $149&lt;{m}_{H}&lt;172\text{ }\text{ }\mathrm{GeV}/{c}^{2}$. A moderate excess of signal-like events relative to the background expectation at the level of 2.0 standard deviations is present in the data for the ${m}_{H}=125\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ search hypothesis. We also present interpretations of the data within the context of a fermiophobic model and an alternative standard model incorporating a fourth generation of fermions. Finally, for the hypothesis of a new particle with mass $125\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, we constrain the coupling strengths of the new particle to ${W}^{\ifmmode\pm\else\textpm\fi{}}$ bosons, $Z$ bosons, and fermions.

The Compact Muon Solenoid (CMS) experiment prepares its Phase-2 upgrade for the high-luminosity era of the LHC operation (HL-LHC). Due to the increase of occupancy, trigger latency and rates, the full electronics of the CMS Drift Tube (DT) chambers will need to be replaced. In the new design, the time bin for the digitization of the chamber signals will be of around 1 ns, and the totality of the signals will be forwarded asynchronously to the service cavern at full resolution. The new backend system will be in charge of building the trigger primitives of each chamber. These trigger primitives contain the information at chamber level about the muon candidates position, direction, and collision time, and are used as input in the L1 CMS trigger. The added functionalities will improve the robustness of the system against ageing. An algorithm based on analytical solutions for reconstructing the DT trigger primitives, called Analytical Method, has been implemented both as a software C++ emulator and in firmware. Its performance has been estimated using the software emulator with simulated and real data samples, and through hardware implementation tests. Measured efficiencies are 96 to 98% for all qualities and time and spatial resolutions are close to the ultimate performance of the DT chambers. A prototype chain of the HL-LHC electronics using the Analytical Method for trigger primitive generation has been installed during Long Shutdown 2 of the LHC and operated in CMS cosmic data taking campaigns in 2020 and 2021. Results from this validation step, the so-called Slice Test, are presented.