Jeffrey Berryhill

We present a study of J/ψ and ψ(2S) production in p¯p collisions, at √s=1.8TeV with the CDF detector at Fermilab. The J/ψ and ψ(2S) mesons are reconstructed using their μ+μ− decay modes. We have measured the inclusive production cross section for both mesons as a function of their transverse momentum in the central region, |η|<0.6. We also measure the fraction of these events originating from b hadrons. We thus extract individual cross sections for J/ψ and ψ(2S) mesons from b-quark decays and prompt production. We find a large excess (approximately a factor of 50) of direct ψ(2S) production compared with predictions from the color singlet model.Received 3 February 1997DOI:https://doi.org/10.1103/PhysRevLett.79.572©1997 American Physical Society

A strong signal for double parton (DP) scattering is observed in a $16{\mathrm{pb}}^{\mathrm{\ensuremath{-}}1}$ sample of $\overline{p}p\ensuremath{\rightarrow}\ensuremath{\gamma}/{\ensuremath{\pi}}^{0}+3\mathrm{jets}+X$ data from the CDF experiment at the Fermilab Tevatron. In DP events, two separate hard scatterings take place in a single $\overline{p}p$ collision. We isolate a large sample of data $(\ensuremath{\sim}14000\mathrm{events})$ of which 53% are found to be DP. The process-independent parameter of double parton scattering, ${\ensuremath{\sigma}}_{\mathrm{eff}},$ is obtained without reference to theoretical calculations by comparing observed DP events to events with hard scatterings in separate $\overline{p}p$ collisions. The result ${\ensuremath{\sigma}}_{\mathrm{eff}}=(14.5\ifmmode\pm\else\textpm\fi{}{1.7}_{\ensuremath{-}2.3}^{+1.7})\mathrm{mb}$ represents a significant improvement over previous measurements, and is used to constrain simple models of parton spatial density. The Feynman $x$ dependence of ${\ensuremath{\sigma}}_{\mathrm{eff}}$ is investigated and none is apparent. Further, no evidence is found for kinematic correlations between the two scatterings in DP events.

We have measured the fraction of $J/\ensuremath{\psi}$ mesons originating from ${\ensuremath{\chi}}_{c}$ meson decays in $p\overline{p}$ collisions at $\sqrt{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.8\mathrm{TeV}$. The fraction, for ${P}_{T}^{J/\ensuremath{\psi}}&gt;4.0\mathrm{GeV}/c$ and $|{\ensuremath{\eta}}^{J/\ensuremath{\psi}}|&lt;0.6$, not including contributions from $b$ flavored hadrons, is $29.7%\ifmmode\pm\else\textpm\fi{}1.7%(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}5.7%(\mathrm{syst})$. We have determined the cross sections for $J/\ensuremath{\psi}$ mesons originating from ${\ensuremath{\chi}}_{c}$ decays and for directly produced $J/\ensuremath{\psi}$ mesons. We have found that direct $J/\ensuremath{\psi}$ production is in excess of the prediction of the color singlet model by the same factor found for direct $\ensuremath{\psi}(2S)$ production.

We have measured the polarization of J/psi and psi(2S) mesons produced in pp collisions at sqrt[s] = 1.8 TeV, using data collected at the Collider Detector at Fermilab during 1992-1995. The polarization of promptly produced J/psi [psi(2S)] mesons is isolated from those produced in B-hadron decay, and measured over the kinematic range 4 [5.5]<P(T)<20 GeV/c and |y|<0.6. For P(T) greater than or approximately equal 12 GeV/c we do not observe significant polarization in the prompt component.

We present a study of the decays B0,+→J/ψωK0,+ using 383×106 B¯¯¯B events obtained with the BABAR detector at PEP-II. We observe Y(3940)→J/ψω, with mass 3914.6+3.8−3.4(stat)±2.0(syst) MeV/c2, and width 34+12−8(stat)±5(syst) MeV. The ratio of B0 and B+ decay to YK is 0.27+0.28−0.23(stat)+0.04−0.01(syst), and the relevant B0 and B+ branching fractions are reported.Received 14 November 2007DOI:https://doi.org/10.1103/PhysRevLett.101.082001©2008 American Physical Society

A bstract We describe a proposal to add a set of very forward detectors to the CMS experiment for the high-luminosity era of the Large Hadron Collider to search for beyond the standard model long-lived particles, such as dark photons, heavy neutral leptons, axion-like particles, and dark Higgs bosons. The proposed subsystem is called FACET for F orward- A perture C MS E x T ension, and will be sensitive to any particles that can penetrate at least 50 m of magnetized iron and decay in an 18 m long, 1 m diameter vacuum pipe. The decay products will be measured in detectors using identical technology to the planned CMS Phase-2 upgrade.

We report on measurements of the Upsilon(1S), Upsilon(2S), and Upsilon(3S) differential cross sections (d(2)sigma/dp(T)dy)(/y/<0.4), as well as on the Upsilon(1S) polarization in p p macro collisions at square root of s = 1.8 TeV using a sample of 77+/-3 pb(-1) collected by the collider detector at Fermilab. The three resonances were reconstructed through the decay Upsilon-->mu(+)mu(-). The measured angular distribution of the muons in the Upsilon(1S) rest frame is consistent with unpolarized meson production.

We have used 106 pb^-1 of data collected with the Collider Detector at Fermilab to search for new particles decaying to dijets. We exclude at the 95% confidence level models containing the following new particles: axigluons and flavor universal colorons with mass between 200 and 980 GeV/c, excited quarks with mass between 80 and 570 GeV/c^2 and between 580 and 760 GeV/c^2, color octet technirhos with mass between 260 and 480 GeV/c^2, W' bosons with mass between 300 and 420 GeV/c^2, and E_6 diquarks with mass between 290 and 420 GeV/c^2.

We present updated measurements of time-dependent CP asymmetries in fully reconstructed neutral B decays containing a charmonium meson. The measurements reported here use a data sample of (465±5)×106 Υ(4S)→B¯¯¯B decays collected with the BABAR detector at the PEP-II asymmetric energy e+e− storage rings operating at the SLAC National Accelerator Laboratory. The time-dependent CP asymmetry parameters measured from JψK0S, JψK0L, ψ(2S)K0S, ηcK0S, χc1K0S, and J/ψK∗(892)0 decays are: Cf=0.024±0.020(stat)±0.016(syst) and −ηfSf=0.687±0.028(stat)±0.012(syst).Received 10 February 2009DOI:https://doi.org/10.1103/PhysRevD.79.072009©2009 American Physical Society

A search for charmonium and other new states is performed in a study of exclusive initial-state-radiation production of D¯¯¯D events from electron-positron annihilations at a center-of-mass energy of 10.58 GeV. The data sample corresponds to an integrated luminosity of 384 fb−1 and was recorded by the BABAR experiment at the PEP-II storage ring. The D¯¯¯D mass spectrum shows clear evidence of the ψ(3770) plus other structures near 3.9, 4.1, and 4.4 GeV/c2. No evidence for Y(4260)→D¯¯¯D is observed, leading to an upper limit of B(Y(4260)→D¯¯¯D)/B(Y(4260)→J/ψπ+π−)<1.0 at 90% confidence level.Received 6 October 2007DOI:https://doi.org/10.1103/PhysRevD.76.111105©2007 American Physical Society

We present a study of excited charm-strange baryon states produced in $e^+e^-$ annihilations at or near a center-of-mass energy of $10.58\mathrm{Ge\kern -0.1em V}$, in a data sample with an integrated luminosity of $384 fb^{-1}$ recorded with the BABAR detector at the PEP-II $e^+e^-$ storage rings at the Stanford Linear Accelerator Center. We study strong decays of charm-strange baryons to $\Lambda_c^+K^0_{\scriptscriptstyle S}$, $\Lambda_c^+K^-$, $\Lambda_c^+K^-\pi^+$, $\Lambda_c^+K^0_{\scriptscriptstyle S}\pi^-$, $\Lambda_c^+K^0_{\scriptscriptstyle S}\pi^-\pi^+$, and $\Lambda_c^+K^-\pi^+\pi^-$. This study confirms the existence of the states $\Xi_c(2980)^+$, $\Xi_c(3077)^+$, and $\Xi_c(3077)^0$, with a more accurate determination of the $\Xi_c(2980)^+$ mass and width. We also present evidence for two new states, $\Xi_c(3055)^+$ and $\Xi_c(3123)^+$, decaying through the intermediate resonant modes $\Sigma_c(2455)^{++}K^-$ and $\Sigma_c(2520)^{++}K^-$, respectively. For each of these baryons, we measure the yield in each final state, determine the statistical significance, and calculate the product of the production cross-section and branching fractions. We also measure the masses and widths of these excited charm-strange baryons.

We describe a measurement of the charge asymmetry of leptons from W boson decays in the rapidity range 0 < |y l | < 2.5 using W → eν, µν events from 110 ± 7 pb -1 of data collected by the CDF detector during 1992-95.The asymmetry data constrain the ratio of d and u quark momentum distributions in the proton over the x range of 0.006 to 0.34 at Q 2 ≈ M 2 W .The asymmetry predictions that use parton distribution functions obtained from previously published CDF data in the central

We report results of a search for CPT and Lorentz violation in B0−¯¯¯B0 oscillations using inclusive dilepton events from 232×106 Υ(4S)→B¯¯¯B decays recorded by the BABAR detector at the PEP-II B Factory at SLAC. We find 2.8σ significance, compatible with no signal, for variations in the complex CPT violation parameter z at the Earth’s sidereal frequency and extract values for the quantities Δaμ in the general Lorentz-violating standard-model extension. The spectral powers for variations in z over the frequency range 0.26 yr−1 to 2.1 solar day−1 are also compatible with no signal.Received 19 November 2007DOI:https://doi.org/10.1103/PhysRevLett.100.131802©2008 American Physical Society

We have measured the cross sections $d^2\sigma/dP_T d\eta$ for production of isolated direct photons in \pbarp collisions at two different center-of-mass energies, 1.8 TeV and 0.63 TeV, using the Collider Detector at Fermilab (CDF). The normalization of both data sets agree with the predictions of Quantum Chromodynamics (QCD) for photon transverse momentum ($P_T$) of 25 GeV/c, but the shapes versus photon $P_T$ do not. These shape differences lead to a significant disagreement in the ratio of cross sections in the scaling variable $x_T (\equiv 2P_T/\sqrt{s}$). This disagreement in the $x_T$ ratio is difficult to explain with conventional theoretical uncertainties such as scale dependence and parton distribution parameterizations.

We present the results of a search for third generation leptoquark (LQ) pairs in $110\ifmmode\pm\else\textpm\fi{}8{\mathrm{pb}}^{\ensuremath{-}1}$of $\overline{p}p$ collisions at $\sqrt{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.8\mathrm{TeV}$ recorded by the Collider Detector at Fermilab. We assume third generation leptoquarks decay to a $\ensuremath{\tau}$ lepton and a $b$ quark with branching ratio $\ensuremath{\beta}$. We observe one candidate event, consistent with standard model background expectations. We place upper limits on $\ensuremath{\sigma}(\overline{p}p\ensuremath{\rightarrow}\mathrm{LQ}\overline{\mathrm{LQ}})\ifmmode \dot{}\else \.{}\fi{}{\ensuremath{\beta}}^{2}$ as a function of the leptoquark mass ${M}_{\mathrm{LQ}}$. We exclude at 95% confidence level scalar leptoquarks with ${M}_{\mathrm{LQ}}&lt;99\mathrm{GeV}{/c}^{2}$, gauge vector leptoquarks with ${M}_{\mathrm{LQ}}&lt;225\mathrm{GeV}{/c}^{2}$, and nongauge vector leptoquarks with ${M}_{\mathrm{LQ}}&lt;170\mathrm{GeV}{/c}^{2}$ for $\ensuremath{\beta}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1$.

We have searched for direct pair production of scalar top and scalar bottom quarks in 88 pb-1 of pp collisions at sqrt[s]=1.8 TeV with the CDF detector. We looked for events with a pair of heavy flavor jets and missing energy, consistent with scalar top (bottom) quark decays to a charm (bottom) quark and a neutralino. The numbers of events that pass our selections show no significant deviation from standard model expectations. We compare our results to the next-to-leading order scalar quark production cross sections to exclude regions in scalar quark-neutralino mass parameter space.

We perform the first three-dimensional measurement of the amplitudes of B→ψ(2S)K* and B→χc1K* decays and update our previous measurement for B→J/ψK*. We use a data sample collected with the BABAR detector at the PEP-II storage ring, corresponding to 232×106 BB¯ pairs. The longitudinal polarization of decays involving a JPC=1++ χc1 meson is found to be larger than that with a 1-- J/ψ or ψ(2S) meson. No direct CP-violating charge asymmetry is observed.Received 5 April 2007DOI:https://doi.org/10.1103/PhysRevD.76.031102©2007 American Physical Society

We present a study of p¯p collisions at √s=1800 and 630 GeV collected using a minimum bias trigger by the CDF experiment in which the data set is divided into two classes corresponding to “soft” and “hard” interactions. For each subsample, the analysis includes measurements of the multiplicity, transverse momentum (pT) spectrum, and the average pT and event-by-event pT dispersion as a function of multiplicity. A comparison of results shows distinct differences in the behavior of the two samples as a function of the center of mass (c.m.) energy. We find evidence that the properties of the soft sample are invariant as a function of c.m. energy.Received 26 October 2001DOI:https://doi.org/10.1103/PhysRevD.65.072005©2002 American Physical Society

This Technical Design Report describes the ongoing developments and plans towards the upgrade of the CMS Level-1 trigger for the High-Luminosity Large Hadron Collider.

We present results from the measurement of the inclusive jet cross section for jet transverse energies from 40 to 465 GeV in the pseudo-rapidity range $0.1<|\eta|<0.7$. The results are based on 87 $pb^{-1}$ of data collected by the CDF collaboration at the Fermilab Tevatron Collider. The data are consistent with previously published results. The data are also consistent with QCD predictions given the flexibility allowed from current knowledge of the proton parton distributions. We develop a new procedure for ranking the agreement of the parton distributions with data and find that the data are best described by QCD predictions using the parton distribution functions which have a large gluon contribution at high $E_T$ (CTEQ4HJ).

We report the results of a search for a W' boson produced in pp; collisions at a center-of-mass energy of 1.8 TeV using a 106 pb(-1) data sample recorded by the Collider Detector at Fermilab. We observe no significant excess of events above background for a W' boson decaying to a top and bottom quark pair. In a model where this boson would mediate interactions involving a massive right-handed neutrino (nu(R)) and have standard model strength couplings, we use these data to exclude a W' boson with mass between 225 and 536 GeV/c(2) at 95% confidence level for M(W')>>M(nu(R)) and between 225 and 566 GeV/c(2) at 95% confidence level for M(W')<M(nu(R)).

We have searched for pair production of the supersymmetric partner of the top quark (stop) in 107 pb(-1) of pp collisions at square root of s=1.8 TeV collected by the Collider Detector at Fermilab (CDF). Each stop is assumed to decay into a lepton, bottom quark, and supersymmetric neutrino. Such a scenario would give rise to events with two leptons, two hadronic jets, and a substantial imbalance of transverse energy. No evidence of such a stop signal has been found. We exclude stop masses in the region (80</=m(t)</=135 GeV/c(2)) in the mass plane of stop versus sneutrino.

The prospects of searches for anomalous production of hadronically decaying weak boson pairs at proposed high-energy muon colliders are reported. Muon-muon collision events are simulated at $\sqrt{s}=6$, 10, and 30 TeV, corresponding to an integrated luminosity of 4, 10, and $10\text{ }\text{ }{\mathrm{ab}}^{\ensuremath{-}1}$, respectively. Simulated $\ensuremath{\mu}\ensuremath{\mu}\ensuremath{\rightarrow}\mathrm{W}\mathrm{W}+\ensuremath{\nu}\ensuremath{\nu}/\ensuremath{\mu}\ensuremath{\mu}$ events are used to set expected constraints on the structure of quartic vector boson interactions in the framework of a dimension-8 effective field theory. Similarly, $\ensuremath{\mu}\ensuremath{\mu}\ensuremath{\rightarrow}\mathrm{W}\mathrm{W}/\mathrm{Z}\mathrm{Z}+\ensuremath{\nu}\ensuremath{\nu}$ events are used to report constraints on the product of the cross section and branching fraction for vector boson fusion production of a heavy neutral Higgs boson decaying to weak boson pairs. These results are interpreted in the context of the Georgi-Machacek model.

We present a study of events with $Z$ bosons and hadronic jets produced in $\overline{p}p$ collisions at a center-of-mass energy of 1.8 TeV. The data consist of 6708 $Z\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}$ decays from $106{\mathrm{pb}}^{\ensuremath{-}1}$ of integrated luminosity collected using the CDF detector at the Fermilab Tevatron Collider. The $Z+\ensuremath{\ge}n$ jet cross sections and jet production properties have been measured for $n\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1$ to 4. The data are compared to predictions of leading-order QCD matrix element calculations with added gluon radiation and simulated parton fragmentation.

We determine the relative branching fractions of semileptonic $B$ decays to charmed final states. The measurement is performed on the recoil from a fully reconstructed $B$ meson in a sample of $362\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected at the $\ensuremath{\Upsilon}(4S)$ resonance with the BABAR detector. A simultaneous fit to a set of discriminating variables is performed on a sample of $\overline{B}\ensuremath{\rightarrow}DX{\ensuremath{\ell}}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{\ensuremath{\ell}}$ decays to determine the contributions from the different channels. We measure $\ensuremath{\Gamma}({B}^{\ensuremath{-}}\ensuremath{\rightarrow}D{\ensuremath{\ell}}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{\ensuremath{\ell}})/\ensuremath{\Gamma}({B}^{\ensuremath{-}}\ensuremath{\rightarrow}DX{\ensuremath{\ell}}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{\ensuremath{\ell}})=0.227\ifmmode\pm\else\textpm\fi{}0.014\ifmmode\pm\else\textpm\fi{}0.016$, $\ensuremath{\Gamma}({B}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}^{*}{\ensuremath{\ell}}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{\ensuremath{\ell}})/\ensuremath{\Gamma}({B}^{\ensuremath{-}}\ensuremath{\rightarrow}DX{\ensuremath{\ell}}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{\ensuremath{\ell}})=0.582\ifmmode\pm\else\textpm\fi{}0.018\ifmmode\pm\else\textpm\fi{}0.030$, and $\ensuremath{\Gamma}({B}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}^{**}{\ensuremath{\ell}}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{\ensuremath{\ell}})/\ensuremath{\Gamma}({B}^{\ensuremath{-}}\ensuremath{\rightarrow}DX{\ensuremath{\ell}}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{\ensuremath{\ell}})=0.191\ifmmode\pm\else\textpm\fi{}0.013\ifmmode\pm\else\textpm\fi{}0.019$ for the charged $B$ sample, and $\ensuremath{\Gamma}(\overline{{B}^{0}}\ensuremath{\rightarrow}D{\ensuremath{\ell}}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{\ensuremath{\ell}})/\ensuremath{\Gamma}(\overline{{B}^{0}}\ensuremath{\rightarrow}DX{\ensuremath{\ell}}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{\ensuremath{\ell}})=0.215\ifmmode\pm\else\textpm\fi{}0.016\ifmmode\pm\else\textpm\fi{}0.013$, $\ensuremath{\Gamma}(\overline{{B}^{0}}\ensuremath{\rightarrow}{D}^{*}{\ensuremath{\ell}}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{\ensuremath{\ell}})/\ensuremath{\Gamma}(\overline{{B}^{0}}\ensuremath{\rightarrow}DX{\ensuremath{\ell}}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{\ensuremath{\ell}})=0.537\ifmmode\pm\else\textpm\fi{}0.031\ifmmode\pm\else\textpm\fi{}0.036$, and $\ensuremath{\Gamma}(\overline{{B}^{0}}\ensuremath{\rightarrow}{D}^{**}{\ensuremath{\ell}}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{\ensuremath{\ell}})/\ensuremath{\Gamma}(\overline{{B}^{0}}\ensuremath{\rightarrow}DX{\ensuremath{\ell}}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{\ensuremath{\ell}})=0.248\ifmmode\pm\else\textpm\fi{}0.032\ifmmode\pm\else\textpm\fi{}0.030$ for the neutral $B$ sample, where uncertainties are statistical and systematic, respectively.

We search for Higgs bosons produced in association with a massive vector boson in 91±7pb−1 of p¯p collisions at √s=1.8TeV recorded by the Collider Detector at Fermilab. We assume the Higgs scalar H0 decays to a b¯b pair with branching ratio β, and we consider the hadronic decays of the vector boson V ( W or Z). Observations are consistent with background expectations. We place 95% confidence level upper limits on σ(p¯p→H0V)β as a function of the scalar mass (MH0) over the range 70<MH0<140GeV/c2. When combined with an analysis of the case where V is a leptonically decaying W, these limits vary from 23 pb at MH0=70GeV/c2 to 17 pb at MH0=140GeV/c2.Received 10 August 1998DOI:https://doi.org/10.1103/PhysRevLett.81.5748©1998 American Physical Society

We report the results of a search for technicolor using 110pb−1 of p¯p collisions recorded by the Collider Detector at Fermilab (CDF). In technicolor models containing a technifamily, color-octet technirhos enhance the pair production of color-triplet technipions, which behave as third-generation leptoquarks. From our previously reported search for third-generation leptoquarks, we present constraints on the production of color-triplet technipions and color-octet technirhos as a function of their masses.Received 5 November 1998DOI:https://doi.org/10.1103/PhysRevLett.82.3206©1999 American Physical Society

The inclusive cross section for J/ψ production times the branching ratio B(J/→ψμ+μ−) has been measured in the forward pseudorapidity region: B×dσ[¯p+→pJ/ψ(pT>10GeV/c,2.1<|η|<2.6)+X]/dη=192±9(stat)±29(syst)pb. The results are based on 74.1±5.2pb−1 of data collected by the CDF Collaboration at the Fermilab Tevatron Collider. The measurements extend earlier measurements of the D0 Collaboration to higher pJ/ψT. In the kinematic range where the experiments partially overlap, these data are in good agreement with previous measurements.Received 8 August 2002DOI:https://doi.org/10.1103/PhysRevD.66.092001©2002 American Physical Society

The CMS Level-1 calorimeter trigger is being upgraded in two stages to maintain performance as the LHC increases pile-up and instantaneous luminosity in its second run. In the first stage, improved algorithms including event-by-event pile-up corrections are used. New algorithms for heavy ion running have also been developed. In the second stage, higher granularity inputs and a time-multiplexed approach allow for improved position and energy resolution. Data processing in both stages of the upgrade is performed with new, Xilinx Virtex-7 based AMC cards.

The prospects of searches for anomalous production of hadronically decaying weak boson pairs at proposed high-energy muon colliders are reported. Muon-muon collision events are simulated at $\sqrt{s}=6$, 10, and 30 TeV, corresponding to an integrated luminosity of $4$, $10$, and $10$ ab$^{-1}$, respectively. Simulated $\mu\mu\rightarrow\mathrm{W}\mathrm{W}+\nu\nu/\mu\mu$ events are used to set expected constraints on the structure of quartic vector boson interactions in the framework of a dimension-8 effective field theory. Similarly, $\mu\mu\rightarrow\mathrm{W}\mathrm{W}/\mathrm{Z}\mathrm{Z}+\nu\nu$ events are used to report constraints on the product of the cross section and branching fraction for vector boson fusion production of a heavy neutral Higgs boson decaying to weak boson pairs. These results are interpreted in the context of the Georgi-Machacek model.

Prospects for searches of anomalous quartic gauge couplings at a future high-energy muon collider using the production of $\mathrm{WW}$ boson pairs are reported. Muon-muon collision events are simulated at $\sqrt{s}=6$ TeV corresponding to an integrated luminosity of $4$ ab$^{-1}$. The simulated events are used to study the $\mathrm{W}\mathrm{W}\nu\nu$ and $\mathrm{W}\mathrm{W}\mu\mu$ final states with the $\mathrm{W}$ bosons decaying hadronically. The events are analyzed to report expected constraints on the structure of quartic vector boson interactions in the framework of dimension-8 effective field theory operators.

We have performed a search for radiative b-hadron decays using events produced in p (p) over bar collisions at roots=1.8 TeV and collected by the Collider Detector at Fermilab. The decays we considered were (B) over bar (0)(d)→(K) over bar*(0)(→K(-)pi(+))gamma, (B) over bar (0)(s)→phi(→K+K-)gamma, Lambda(b)(0)→Lambda(→ppi(-))gamma, and their charge conjugates. Two independent methods to identify photons from such decays were employed. In the first method, the photon was detected in the electromagnetic calorimeter. In the second method, the photon was identified by an electron-positron pair produced through the external photon conversion before the tracking detector volume. By combining the two methods we obtain upper limits on the branching fractions for the (B) over bar (0)(d), (B) over bar (0)(s), and Lambda(b)(0) radiative decays which, at the 95% confidence level, are found to be B((B) over bar (0)(d)→(K) over bar*(0)gamma) lt 1.4x10(-4), B((B) over bar (0)(s)→phigamma) lt 1.6x10(-4), and B(Λ(0)(b)→Lambdagamma) lt 1.9x10(-3).

The Compact Muon Solenoid (CMS) experiment is currently installing upgrades to their Calorimeter Trigger for LHC Run 2 to ensure that the trigger thresholds can stay low, and physics data collection will not be compromised. The electronics will be upgraded in two stages. Stage-1 for 2015 will upgrade some electronics and links from copper to optical in the existing calorimeter trigger so that the algorithms can be improved and we do not lose valuable data before stage-2 can be fully installed by 2016. Stage-2 will fully replace the calorimeter trigger at CMS with a micro-TCA and optical link system. It requires that the updates to the calorimeter back-ends, the source of the trigger primitives, be completed. The new system's boards will utilize Xilinx Virtex-7 FPGAs and have hundreds of high-speed links operating at up to 10 Gbps to maximize data throughput. The integration, commissioning, and installation of stage-1 in 2015 will be described, as well as the integration and parallel installation of the stage-2 in 2015, for a fully upgraded CMS calorimeter trigger in operation by 2016.

Author(s): Aubert, B; Bona, M; Boutigny, D; Karyotakis, Y; Lees, JP; Poireau, V; Prudent, X; Tisserand, V; Zghiche, A; Garra Tico, J; Grauges, E; Lopez, L; Palano, A; Pappagallo, M; Eigen, G; Stugu, B; Sun, L; Abrams, GS; Battaglia, M; Brown, DN; Button-Shafer, J; Cahn, RN; Groysman, Y; Jacobsen, RG; Kadyk, JA; Kerth, LT; Kolomensky, YG; Kukartsev, G; Lopes Pegna, D; Lynch, G; Mir, LM; Orimoto, TJ; Osipenkov, IL; Ronan, MT; Tackmann, K; Tanabe, T; Wenzel, WA; Del Amo Sanchez, P; Hawkes, CM; Watson, AT; Koch, H; Schroeder, T; Walker, D; Asgeirsson, DJ; Cuhadar-Donszelmann, T; Fulsom, BG; Hearty, C; Mattison, TS; McKenna, JA; Khan, A; Saleem, M; Teodorescu, L; Blinov, VE; Bukin, AD; Druzhinin, VP; Golubev, VB; Onuchin, AP; Serednyakov, SI; Skovpen, YI; Solodov, EP; Todyshev, KY; Bondioli, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, AJ; Lund, P; Mandelkern, M; Martin, EC; Stoker, DP; Abachi, S; Buchanan, C; Foulkes, SD; Gary, JW; Liu, F; Long, O; Shen, BC; Vitug, GM; Zhang, L; Paar, HP; Rahatlou, S; Sharma, V; Berryhill, JW; Campagnari, C; Cunha, A | Abstract: We study the decay B 0 → ρ 0 ρ 0 in a sample of about 427 million γ(4S) → BB decays collected with the BABAR detector at the PEP-II asymmetric-energy e + e - collider at SLAC. We find the branching fraction B = (0.84 ± 0.29 ± 0.17) × 10-6 and longitudinal polarization fraction of fL = 0.70 ± 0.14 ± 0.05, where the first uncertainty is statistical, and the second is systematic. The evidence for the B 0 → ρ 0 ρ 0 signal has 3.6σ significance. We investigate the proper-time dependence of the longitudinal component in the decay and measure the CP-violating coefficients S00 L = (0.5± 0.9 ± 0.2) and C00 L = (0.4 ± 0.9 ± 0.2), corresponding to the sine and cosine terms in the time evolution of asymmetry. We study the implication of these results for penguin contributions in B → ρρ decays and for the CKM unitarity angle α.

Author(s): Aubert, B; Bona, M; Boutigny, D; Karyotakis, Y; Lees, JP; Poireau, V; Prudent, X; Tisserand, V; Zghiche, A; Garra Tico, J; Grauges, E; Lopez, L; Palano, A; Pappagallo, M; Eigen, G; Stugu, B; Sun, L; Abrams, GS; Battaglia, M; Brown, DN; Button-Shafer, J; Cahn, RN; Groysman, Y; Jacobsen, RG; Kadyk, JA; Kerth, LT; Kolomensky, YG; Kukartsev, G; Lopes Pegna, D; Lynch, G; Mir, LM; Orimoto, TJ; Osipenkov, IL; Ronan, MT; Tackmann, K; Tanabe, T; Wenzel, WA; Del Amo Sanchez, P; Hawkes, CM; Watson, AT; Koch, H; Schroeder, T; Walker, D; Asgeirsson, DJ; Cuhadar-Donszelmann, T; Fulsom, BG; Hearty, C; Mattison, TS; McKenna, JA; Khan, A; Saleem, M; Teodorescu, L; Blinov, VE; Bukin, AD; Druzhinin, VP; Golubev, VB; Onuchin, AP; Serednyakov, SI; Skovpen, YI; Solodov, EP; Todyshev, KY; Bondioli, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, AJ; Lund, P; Mandelkern, M; Martin, EC; Stoker, DP; Abachi, S; Buchanan, C; Foulkes, SD; Gary, JW; Liu, F; Long, O; Shen, BC; Vitug, GM; Zhang, L; Paar, HP; Rahatlou, S; Sharma, V; Berryhill, JW; Campagnari, C; Cunha, A | Abstract: We present preliminary results of a search for B → Xdγ decays with a hadronic mass 1.0 GeV/c2 l M(Xd) l 1.8 GeV/c2. We consider seven final states with up to four charged pions and one neutral pion or η, which correspond to about 50% of the total Xd fragmentation in this mass range. Based on a sample of 383 million B B events collected by the BaBar experiment at PEPII, we measure a partial branching fraction P7 Xd=1 B(B → Xdγ)|(1.0GeV/c2 l M(Xd) l 1.8GeV/c2) = (3.1±0.9+0.6 -0.5 ±0.5) · 10-6, where the uncertainties are statistical, systematic and model-dependent respectively.

The silicon vertex tracker (SVT) of the BaBar experiment at PEP II is briefly described. It consists of five layers of double-sided AC-coupled silicon strip detectors, constituting the core of the BaBar tracking system. After six years of operation, some unexpected effects have appeared. In particular, a shift in the pedestal for the channels of the AToM readout chips that are most exposed to radiation has been observed. The behavior has been understood and reproduced in AToM chip irradiations with 1-GeV electrons at Elettra (Trieste) and the results of the studies are presented here. A second unexpected behavior has been detected, consisting of an anomalous increase in the bias leakage current for the modules in the outer layers. The effect is beam-related but not directly linked to radiation damage, as suggested by the fact that it is not present in the inner layers. The cause has been understood and the conclusions are presented here. The effect has been reproduced in a qualitative way in the laboratory. Over the next three years the luminosity is predicted to increase by a factor of three, leading to radiation and occupancy levels significantly exceeding the detector design. Estimates of future radiation doses and occupancies are shown together with the extrapolated detector performance and lifetime, in light of the new observations. Upgrade scenarios to deal with the increased luminosity and backgrounds are discussed.

Using a sample of 227 million $\Upsilon(4S) \to B \bar{B}$ events collected with the $BABAR$ detector at the PEP-II $B$ Factory in 1999--2004, we study $B^- \to D^0 K^*(892)^-$ decays where $K^{*-} \to K^0_S \pi^-$ and $D^0 \to K^-\pi^+, K^- \pi^+ \pi^0, K^-\pi^+ \pi^+ \pi^-$ (non-CP final states), $K^+ K^-, \pi^+ \pi^- (CP+$ eigenstates), $K^0_S~\pi^0, K^0_S \phi$ and $K^0_S \omega (CP-$ eigenstates). The partial rate charge asymmetries $\mathcal{A}_{CP}$ and the ratios $\mathcal{R}_{CP}$ defined in the literature as the sum of the $B^+$ and $B^-$ partial rates to a charged $K^*$ and a $D^0 CP$-eigenstate divi ded by the $B \to D^0 K^*$ decay rate, %of the \ensuremath{\Bu}\xspace\xspace m \ensuremath{\to}\xspace \Dcp \ensuremath{K^*}\xspacepm branch ing fractions summed over %\B charge to the \ensuremath{B^-}\xspace \xspace\ensuremath{\to}\xspace \ensuremath{D^0}\xspace \ensu remath{K^{*-}}\xspace branching fraction are sensitive to the angle $\gamma$ of the CKM unitarity triangle. We measure: \mathcal{A}_{CP+} &=&-0.09 \pm 0.20 (stat.) \pm 0.06 (syst.) \mathcal{A}_{CP-} &=& -0.33 \pm 0.34 (stat.) \pm 0.10 (syst.) (+1.15 \pm 0.12) \cdot (\mathcal{A}_{CP-} - \mathcal{A}_{CP+}) \mathcal{R}_{CP+} &=& +1.77 \pm 0.37 (stat.) \pm 0.12 (syst.) \mathcal{R}_{CP-} &=& +0.76 \pm 0.29 (stat.) \pm 0.06 (syst.) ^{- 0.04}_{- 0.14} The third uncertainty quoted for the CP- measurements reflects possible interference effects in the final states with $\phi$ and $\omega$ resonances. All results are preliminary.

We present evidence for the flavor-changing neutral current decay B {yields} K*{ell}{sup +}{ell}{sup -} and a measurement of the branching fraction for the related process B {yields} K{ell}{sup +}{ell}{sup -}, where {ell}{sup +}{ell}{sup -} is either an e{sup +}e{sup -} or {mu}{sup +}{mu}{sup -} pair. These decays are highly suppressed in the Standard Model, and they are sensitive to contributions from new particles in the intermediate state. The data sample comprises 123 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II e{sup +}e{sup -} storage ring. Averaging over K* isospin and lepton flavor, we obtain the branching fractions {Beta}(B {yields} K{ell}{sup +}{ell}{sup -}) = (0.65{sub -0.13}{sup +0.14} {+-} 0.04) x 10{sup -6} {Beta}(B {yields} K*{ell}{sup +}{ell}{sup -}) = (0.88{sub -0.29}{sup +0.33} {+-} 0.10) x 10{sup -6}, where the uncertainties are statistical and systematic, respectively. The significance of the B {yields} K{ell}{sup +}{ell}{sup -} signal is over 8{sigma}, while for B {yields} K*{ell}{sup +}{ell}{sup -} it is 3.3{sigma}.

We have measured the polarization of J/psi and psi(2S) mesons produced in p (p) over bar collisions at root s = 1.8 TeV. using data collected at the Collider Detector at Fermilab during 1992-1995. The polarization of promptly produced J/psi [psi(2S)] mesons is isolated from those produced in B-hadron decay, and measured over the kinematic range 4 [5.5] < P-T < 20 GeV/c and \y < 0.6. For P-T greater than or similar to 12 GeV/c we do not observe significant polarization in the prompt component.

We present the results of a search in p$\bar{b}$ collisions at √s = 1.8 TeV for anomalous production of events containing a photon with large transverse energy and a lepton (e or μ) with large transverse energy, using 86 pb-1 of data collected at the Collider Detector at Fermilab during the 1994-95 collider run at the Fermilab Tevatron. The presence of large missing transverse energy (ET), additional photons, or additional leptons in these events is also analyzed. The results are consistent with standard model expectations, with the possible exception of photon-lepton events with large ET, for which the probability of a statistical fluctuation of the standard model expectation up to and above the observed level is 0.7%.

This Letter describes a direct measurement of the W boson total decay width, Gamma(W), using the Collider Detector at Fermilab. The measurement uses an integrated luminosity of 90 pb-L, collected during the 1994-1995 run of the Fermilab Tevatron pr collider. The width is determined by normalizing predicted signal and background distributions to 49 843 W --> ev candidates and 21 806 W --> mu nu candidates in the transverse-mass region M-T < 200 GeV and then fitting the predicted shape to the 438 electron events and 196 muon events in the high-M-T region, 100 < M-T < 200 GeV. The result is Gamma(W) = 2.04 +/- 0.11(stat) +/- 0.09(syst) GeV.

Reference EPFL-ARTICLE-173148 URL: http://arxiv.org/abs/hep-ph/0112141 Record created on 2011-12-23, modified on 2017-05-12

We present the results of a search in $p\overline{p}$ collisions at $sqrt{s}$ = 1:8 TeV for anomalous production of events containing a photon with large transverse energy and a lepton (e or $\mu$) with large transverse energy, using 86 $pb^{-1}$ of data collected at the Collider Detector at Fermilab during the 1994-95 collider run at the Fermilab Tevatron. The presence of large missing transverse energy slash-($E_T$), additional photons, or additional leptons in these events is also analyzed. The results are consistent with standard model expectations, with the possible exception of photon-lepton events with large slash-$E_T$, for which the probability of a statistical uctuation of the standard model expectation up to and above the observed level is 0.7%.

We present the results of a search for third generation leptoquark (LQ) pairs in 110{plus_minus}8pb{sup -1} of {bar p}p collisions at {radical}(s)=1.8TeV recorded by the Collider Detector at Fermilab. We assume third generation leptoquarks decay to a {tau} lepton and a b quark with branching ratio {beta}. We observe one candidate event, consistent with standard model background expectations. We place upper limits on {sigma}({bar p} p{r_arrow}LQ{ovr LQ}){center_dot}{beta}{sup 2} as a function of the leptoquark mass M{sub LQ}. We exclude at 95{percent} confidence level scalar leptoquarks with M{sub LQ}{lt}99GeV/c{sup 2}, gauge vector leptoquarks with M{sub LQ}{lt}225GeV/c{sup 2}, and nongauge vector leptoquarks with M{sub LQ}{lt}170GeV/c{sup 2} for {beta}=1. {copyright} {ital 1997} {ital The American Physical Society}

We present a measurement of the B{sup 0}{leftrightarrow}{bar B}{sup 0} oscillation frequency using a flavor tagging method based on correlations of B meson flavor with the charge of other particles produced in p{bar p} collisions at {radical}(s)=1.8 TeV. Such correlations are expected to arise from b quark hadronization and from B{sup {asterisk}{asterisk}} decays. We partially reconstruct B mesons using the semileptonic decays B{sup 0}{r_arrow}l{sup +}D{sup ({asterisk}){minus}} X and B{sup +}{r_arrow}l{sup +}{bar D}{sup 0}X. From the oscillation frequency, we obtain the mass difference between the two B{sup 0} mass eigenstates, {Delta}m{sub d}=0.471{sup +0.078}{sub {minus}0.068} (stat){plus_minus}0.034(syst ){h_bar} ps{sup {minus}1}, and measure the efficiency and purity of this flavor tagging method for both charged and neutral B mesons. {copyright} {ital 1998} {ital The American Physical Society}

A new technique to measure the ratio of [ital b] quark fragmentation fractions in p[bar p] collisions is described. Using a 70-pb[sup [minus]1] sample of low-mass dimuon trigger data recorded with the Collider Detector at Fermilab, we identify [ital B] mesons by observing the double semileptonic decays b[r arrow]c[mu]X with c[r arrow]s[mu]X. By counting the numbers of K[sup [asterisk]](892)[sup 0], K[sup [asterisk]](892)[sup +], and [phi](1020) mesons produced in association with these muon pairs, we measure the ratio of strange to nonstrange [ital B] meson production to be f[sub s]/(f[sub u]+f[sub d])=[21.0[plus minus]3.6(stat)[sub [minus]3.0][sup +3.8](syst)][percent]. This measurement is the most precise available from hadron collisions to date. Limits on the branching fractions of semileptonic charm meson decays with K[sub 1](1270), K[sub 1][sup [asterisk]](1410), and K[sub 2][sup [asterisk]](1430) mesons in the final state are also obtained. [copyright] [ital 1999] [ital The American Physical Society]

We search for new long-lived particles which decay to Z{sup 0} bosons by looking for Z{sup 0}{r_arrow}e{sup +}e{sup {minus}} decays with displaced vertices. We find no evidence for parent particles of the Z{sup 0} with long lifetimes in 90thinsppb{sup {minus}1} of data from the CDF experiment at Fermilab. We set a cross section limit as a function of the lifetime of the parent particle for both a generic Z{sup 0} parent and a fourth-generation, charge {minus} (1) /(3) quark that decays into Z{sup 0}b. {copyright} {ital 1998} {ital The American Physical Society}

A search for B{sup 0}{sub s}-{ovr B}{sup 0}{sub s} oscillations is performed in a sample of B{sup 0}{sub s} semileptonic decays collected using dilepton triggers at the Tevatron Collider during 1992{endash}1995. The B{sup 0}{sub s} is reconstructed using {phi} meson-lepton correlations; its initial production flavor is determined with the second lepton in the event. From a signal of 1068 with a B{sup 0}{sub s} purity of 61{percent} , we obtain a limit on the B{sup 0}{sub s}-{ovr B}{sup 0}{sub s} oscillation frequency of {Delta}m{sub s}{gt}5.8 ps{sup {minus}1} at 95{percent} confidence level. {copyright} {ital 1999} {ital The American Physical Society}

We present a study of J/{psi} and {psi}(2S) production in p{bar p} collisions, at {radical}(s)=1.8 TeV with the CDF detector at Fermilab. The J/{psi} and {psi}(2S) mesons are reconstructed using their {mu}{sup +}{mu}{sup {minus}} decay modes. We have measured the inclusive production cross section for both mesons as a function of their transverse momentum in the central region, {vert_bar}{eta}{vert_bar}{lt}0.6 . We also measure the fraction of these events originating from b hadrons. We thus extract individual cross sections for J/{psi} and {psi}(2S) mesons from b -quark decays and prompt production. We find a large excess (approximately a factor of 50) of direct {psi}(2S) production compared with predictions from the color singlet model. {copyright} {ital 1997} {ital The American Physical Society}

A strong signal for double parton (DP) scattering is observed in a 16pb{sup {minus}1} sample of {bar p}p{r_arrow}{gamma}/{pi}{sup 0}+3jets+X data from the CDF experiment at the Fermilab Tevatron. In DP events, two separate hard scatterings take place in a single {bar p}p collision. We isolate a large sample of data ({approximately}14000 events) of which 53{percent} are found to be DP. The process-independent parameter of double parton scattering, {sigma}{sub eff}, is obtained without reference to theoretical calculations by comparing observed DP events to events with hard scatterings in separate {bar p}p collisions. The result {sigma}{sub eff}=(14.5{plus_minus}1.7{sub {minus}2.3}{sup +1.7})mb represents a significant improvement over previous measurements, and is used to constrain simple models of parton spatial density. The Feynman x dependence of {sigma}{sub eff} is investigated and none is apparent. Further, no evidence is found for kinematic correlations between the two scatterings in DP events. {copyright} {ital 1997} {ital The American Physical Society}

We report the observations of the decays B{sup +}{r_arrow}{psi}(2S)K{sup +} and B{sup 0}{r_arrow}{psi}(2S)K{sup {asterisk}}(892){sup 0} in p{bar p} collisions at a center-of-mass energy of 1.8 TeV using a 110thinsppb{sup {minus}1} data sample recorded by the Collider Detector at Fermilab. We also reconstruct the decays B{sup +}{r_arrow}J/{psi}K{sup +} and B{sup 0}{r_arrow}J/{psi}K{sup {asterisk}}(892){sup 0} and measure the six ratios of branching fractions of these four decays. The relative branching-fraction results are shown to be consistent with phenomenological factorization calculations of hadronic B-meson decays. We use the world-average branching fraction B(B{sup +}{r_arrow}J/{psi}K{sup +}) to derive B{bold (}B{sup +}{r_arrow}{psi}(2S)K{sup +}{bold )}=(0.56{plus_minus}0.08{plus_minus}0.10){times}10{sup {minus}3}, B{bold (}B{sup 0}{r_arrow}{psi}(2S)K{sup {asterisk}}(892){sup 0}{bold )}=(0.92{plus_minus}0.20{plus_minus}0.16){times}10{sup {minus}3}, and B{bold (}B{sup 0}{r_arrow}J/{psi}K{sup {asterisk}}(892){sup 0}{bold )}=(1.78{plus_minus}0.14{plus_minus}0.29){times}10{sup {minus}3}, where the first and second uncertainties are statistical and systematic, respectively. {copyright} {ital 1998} {ital The American Physical Society}

We present a measurement of the time-dependent asymmetry in the rate for {ovr B}{sup thinsp0}{sub d} versus B{sup 0}{sub d} decays to J/{psi}K{sup 0}{sub S} . A nonzero asymmetry would be an indication of CP violation, and within the standard model this may be used to measure the CP -violation parameter sin(2{beta}) . A total of 198{plus_minus}17 B{sup 0}{sub d}/{ovr B}{sup thinsp0}{sub d} decays were observed in p{ovr p} collisions at {radical} (s) =1.8 TeV by the CDF detector at the Fermilab Tevatron. B{sup 0}{sub d} and {ovr B}{sup thinsp0}{sub d} are distinguished by a technique based on charge correlations from hadronization of the b quark. Our analysis results in sin(2{beta})=1.8{plus_minus}1.1(stat ){plus_minus}0.3(syst) . {copyright} {ital 1998} {ital The American Physical Society }

We present results of a search for W{sup +}W{sup -} production through the leptonic decay channel W{sup +}W{sup -}{r_arrow}l{sup +}l{sup -}{nu}{ovr {nu}} in {ovr p}p collisions at {radical}(s)=1.8TeV. In a 108pb{sup -1} data sample recorded with the Collider Detector at Fermilab, five W{sup +}W{sup -} candidates are found with an expected standard model background of 1.2{plus_minus}0.3 events. The W{sup +}W{sup -} production cross section is measured to be {sigma}({ovr p}p{r_arrow} W{sup +}W{sup -})=10.2{sup +6.3}{sub -5.1}(stat){plus_minus}1.6(syst)pb, in agreement with the standard model prediction. Limits on WW{gamma} and WWZ anomalous couplings are presented. {copyright} {ital 1997} {ital The American Physical Society}

We report the results of a search for technicolor using 110 pb{sup {minus}1} of p{ovr p} collisions recorded by the Collider Detector at Fermilab (CDF). In technicolor models containing a technifamily, color-octet technirhos enhance the pair production of color-triplet technipions, which behave as third-generation leptoquarks. From our previously reported search for third-generation leptoquarks, we present constraints on the production of color-triplet technipions and color-octet technirhos as a function of their masses. {copyright} {ital 1999} {ital The American Physical Society}

We present measurements of correlated b{bar b} cross sections, {mu}-{mu} correlations, the average B{sup 0}{bar B}{sup 0} mixing parameter {bar {chi}}, and a limit on the {ital CP}-violating parameter {epsilon}{sub B}. For these measurements, we use muon pairs from b{bar b} double semileptonic decays. The data used in this analysis were taken with the Collider Detector at Fermilab and represent an integrated luminosity of 17.4{plus_minus}0.6 pb{sup {minus}1}. The results concerning b{bar b} production correlations are compared to predictions of next-to-leading order QCD computations. {copyright} {ital 1997} {ital The American Physical Society}

We have searched for heavy neutral gauge bosons (Z{sup {prime}}) in dielectron and dimuon decay modes using 110 pb{sup {minus}1} of {ital {bar p}}{ital p} collisions at {radical}(s)=1.8 TeV collected with the Collider Detector at Fermilab. We present a limit on the production cross section times branching ratio of a Z{sup {prime}} boson decaying into dileptons as a function of Z{sup {prime}} mass. For mass M{sub Z{sup {prime}}}{gt}600 GeV /c{sup 2}, the upper limit is 40fb at 95% confidence level. We set the lower mass limits of 690, 590, 620, 595, 565, 630, and 600 GeV/c{sup 2} for Z{sup {prime}}{sub SM}, Z{sub {psi}}, Z{sub {eta}}, Z{sub {chi}}, Z{sub I}, Z{sub LR}, and Z{sub ALRM}, respectively. {copyright} {ital 1997} {ital The American Physical Society}

We present a measurement of Z{sup 0} boson and Drell-Yan production cross sections in {bar p}p collisions at {radical} (s) =1.8 TeV using a sample of 107 pb{sup {minus}1} accumulated by the Collider Detector at Fermilab. The Drell-Yan cross section is measured in the mass range of M{sub {mu}{mu}}{gt}40 GeV/c{sup 2}. We compare the measurements with the predictions of quantum chromodynamics in both leading order and next-to-leading order, incorporating the recent parton distribution functions. The measurements are consistent with the standard model expectations. {copyright} {ital 1999} {ital The American Physical Society}

We present a measurement of the mass difference [Delta]m[sub d] for the B[sup 0] meson and the statistical power of the [ital b] flavor tagging methods used. The measurement uses 90 pb[sup [minus]1] of data from p[bar p] collisions at [radical] (s) =1.8 TeV collected with the CDF detector. An inclusive lepton trigger is used to collect a large sample of [ital B] hadron semileptonic decays. The mass difference [Delta]m[sub d] is determined from the proper time dependence of the fraction of [ital B] hadrons that undergo flavor oscillations. The flavor at decay is inferred from the charge of the lepton from semileptonic [ital B] decay. The initial flavor is inferred by determining the flavor of the other [ital B] hadron produced in the collision, either from its semileptonic decay (soft-lepton tag) or from its jet charge. The measurement yields [Delta]m[sub d]=(0.500[plus minus]0.052[plus minus]0.043)[h bar] ps[sup [minus]1], where the first uncertainty is statistical and the second uncertainty is systematic. The statistical powers ([epsilon]D[sup 2]) of the soft-lepton and jet-charge flavor taggers are (0.91[plus minus]0.10[plus minus]0.11)[percent] and (0.78[plus minus]0.12[plus minus]0.08)[percent], respectively. [copyright] [ital 1999] [ital The American Physical Society]

B{sub d}{sup 0}-{bar B}{sub d}{sup 0} oscillations are observed in {open_quotes}self-tagged{close_quotes} samples of partially reconstructed B mesons decaying into a lepton and a charmed meson collected in p{bar p} collisions at {radical} (s) =1.8thinspTeV. A flavor tagging technique is employed which relies upon the correlation between the flavor of B mesons and the charge of a nearby particle. We measure the flavor oscillation frequency to be {Delta}m{sub d}=0.471{sub {minus}0.068}{sup +0.078}{plus_minus}0.034thinspps{sup {minus}1}. The tagging method is also demonstrated in exclusive samples of B{sub u}{sup +}{r_arrow}J/{psi}K{sup +} and B{sub d}{sup 0}{r_arrow}J/{psi}K{sup {asterisk}0}(892), where similar flavor-charge correlations are observed. The tagging characteristics of the various samples are compared with each other, and with Monte Carlo simulations. {copyright} {ital 1998} {ital The American Physical Society}

The SVT is an online tracker for the CDF upgrade which will reconstruct 2D tracks using information from the Silicon VerteX detector (SVXII) and Central Outer Tracker (COT). The precision measurement of the track impact parameter will then be used to select and record large samples of B hadrons. We discuss the overall architecture, algorithms, and hardware implementation of the system.

We present a measurement of the t{bar t} production cross section in p{bar p} collisions at {radical}(s)=1.8 TeV using an integrated luminosity of 109 pb{sup {minus}1} collected with the Collider Detector at Fermilab. The measurement uses t{bar t} decays into final states which contain one or two high transverse momentum leptons and multiple jets, and final states which contain only jets. Using acceptances appropriate for a top quark mass of 175 GeV/c{sup 2} , we find {sigma}{sub t{bar t}}=7.6{sup +1 .8}{sub {minus}1.5} pb . {copyright} {ital 1998} {ital The American Physical Society}

We present a search for the flavor-changing neutral current decays B{sub d}{sup 0}{r_arrow}{mu}{sup +}{mu}{sup {minus}} and B{sub s}{sup 0}{r_arrow}{mu}{sup +}{mu}{sup {minus}} in p{bar p} collisions at {radical} (s) =1.8TeV, using 98pb{sup {minus}1} of data collected at the Collider Detector at Fermilab. We find one candidate event for these decays, which is consistent with the background estimates, and set upper limits on the branching fractions of B(B{sub d}{sup 0}{r_arrow}{mu}{sup +}{mu}{sup {minus}}){lt}8.6{times}10{sup {minus}7} and B(B{sub s}{sup 0}{r_arrow}{mu}{sup +}{mu}{sup {minus}}){lt}2.6{times}10{sup {minus}6} at 95{percent} confidence level. {copyright} {ital 1998} {ital The American Physical Society}