M. A. Ciocci

We present a new measurement of the inclusive and differential production cross sections of $J/\psi$ mesons and $b$-hadrons in proton-antiproton collisions at $\sqrt{s}=1960$ GeV. The data correspond to an integrated luminosity of 39.7 pb$^{-1}$ collected by the CDF Run II detector. We find the integrated cross section for inclusive $J/\psi$ production for all transverse momenta from 0 to 20 GeV/$c$ in the rapidity range $|y|<0.6$ to be $4.08 \pm 0.02 (stat)^{+0.36}_{-0.33} (syst) \mu {\rm b}$. We separate the fraction of $J/\psi$ events from the decay of the long-lived $b$-hadrons using the lifetime distribution in all events with $p_T(J/\psi) > 1.25$ GeV/$c$. We find the total cross section for $b$-hadrons, including both hadrons and anti-hadrons, decaying to $J/\psi$ with transverse momenta greater than 1.25 GeV/$c$ in the rapidity range $|y(J/\psi)|<0.6$, is $ 0.330 \pm 0.005 (stat) ^{+0.036}_{-0.033} (syst) ~\mu{\rm b}$. Using a Monte Carlo simulation of the decay kinematics of $b$-hadrons to all final states containing a $J/\psi$, we extract the first measurement of the total single $b$-hadron cross section down to zero transverse momentum at $\sqrt{s}=1960$ GeV. We find the total single $b$-hadron cross section integrated over all transverse momenta for $b$-hadrons in the rapidity range $|y|<0.6$ to be $ 17.6 \pm 0.4 (stat)^{+2.5}_{-2.3} (syst) \mu{\rm b}$.

We report the observation of a narrow state decaying into $J/\ensuremath{\psi}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ and produced in $220\text{ }{\mathrm{p}\mathrm{b}}^{\ensuremath{-}1}$ of $\stackrel{\ifmmode \bar{}\else \={}\fi{}}{p}p$ collisions at $\sqrt{s}=1.96\text{ }\mathrm{T}\mathrm{e}\mathrm{V}$ in the CDF II experiment. We observe $730\ifmmode\pm\else\textpm\fi{}90$ decays. The mass is measured to be $3871.3\ifmmode\pm\else\textpm\fi{}0.7(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t})\ifmmode\pm\else\textpm\fi{}0.4(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})\text{ }\mathrm{M}\mathrm{e}\mathrm{V}/{c}^{2}$, with an observed width consistent with the detector resolution. This is in agreement with the recent observation by the Belle Collaboration of the $X(3872)$ meson.

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 $0.088\ifmmode\pm\else\textpm\fi{}0.013$.

Evidence is reported for a narrow structure near the J/psivarphi threshold in exclusive B;{+} --> J/psivarphiK;{+} decays produced in p[over]p collisions at sqrt[s] = 1.96 TeV. A signal of 14 +/- 5 events, with statistical significance in excess of 3.8 standard deviations, is observed in a data sample corresponding to an integrated luminosity of 2.7 fb;{-1}, collected by the CDF II detector. The mass and natural width of the structure are measured to be 4143.0 +/- 2.9(stat) +/- 1.2(syst) MeV/c;{2} and 11.7_{-5.0};{+8.3}(stat) +/- 3.7(syst) MeV/c;{2}.

We present a measurement of the $t\overline{t}$ production cross section using events with one charged lepton and jets from $p\overline{p}$ collisions at a center-of-mass energy of 1.96 TeV. In these events, heavy flavor quarks from top quark decay are identified with a secondary vertex tagging algorithm. From $162\text{ }\text{ }\mathrm{p}{\mathrm{b}}^{\ensuremath{-}1}$ of data collected by the Collider Detector at Fermilab, a total of 48 candidate events are selected, where $13.5\ifmmode\pm\else\textpm\fi{}1.8$ events are expected from background contributions. We measure a $t\overline{t}$ production cross section of ${5.6}_{\ensuremath{-}1.1}^{+1.2}(\mathrm{stat}.{)}_{\ensuremath{-}0.6}^{+0.9}(\mathrm{syst}.)\text{ }\text{ }\mathrm{pb}$.

We present a search for new particles which produce narrow two-jet (dijet) resonances using proton-antiproton collision data corresponding to an integrated luminosity of $1.13\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected with the CDF II detector. The measured dijet mass spectrum is found to be consistent with next-to-leading-order perturbative QCD predictions, and no significant evidence of new particles is found. We set upper limits at the 95% confidence level on cross sections times the branching fraction for the production of new particles decaying into dijets with both jets having a rapidity magnitude $|y|&lt;1$. These limits are used to determine the mass exclusions for the excited quark, axigluon, flavor-universal coloron, ${E}_{6}$ diquark, color-octet techni-$\ensuremath{\rho}$, ${W}^{\ensuremath{'}}$, and ${Z}^{\ensuremath{'}}$.

We present measurements of the forward-backward charge asymmetry in top pair production using 1.9 fb;{-1} of pp[over ] collisions at sqrt[s]=1.96 TeV recorded with the Collider Detector at Fermilab II. Correcting for acceptance and measurement dilutions we obtain parton-level asymmetries of A_{FB};{pp[over ]}=0.17+/-0.08 in the pp[over ] frame and A_{FB};{tt[over ]}=0.24+/-0.14 in the tt[over ] frame. The values are consistent with the standard model expectation and disfavor exotic production mechanisms with significant negative values.

We present an analysis of angular distributions and correlations of the X(3872) particle in the exclusive decay mode X(3872)->J/psi pi+ pi- with J/psi->mu+ mu-. We use 780 pb -1 of data from ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We derive constraints on spin, parity, and charge conjugation parity of the X(3872) particle by comparing measured angular distributions of the decay products with predictions for different JPC hypotheses. The assignments JPC = 1++ and 2-+ are the only ones consistent with the data.

We report on measurements of differential cross sections dsigma/dp(T) for prompt charm meson production in ppmacr; collisions at sqrt[s]=1.96 TeV using 5.8+/-0.3 pb(-1) of data from the CDF II detector at the Fermilab Tevatron. The data are collected with a new trigger that is sensitive to the long lifetime of hadrons containing heavy flavor. The charm meson cross sections are measured in the central rapidity region |y|</=1 in four fully reconstructed decay modes: D0-->K-pi(+), D(*+)-->D0pi(+), D+-->K-pi(+)pi(+), D(+)(s)-->phipi(+), and their charge conjugates. The measured cross sections are compared to theoretical calculations.

We present a measurement of the inclusive jet cross section in p¯p collisions at √s=1.96 TeV based on data collected by the CDF II detector with an integrated luminosity of 1.13 fb−1. The measurement was made using the cone-based midpoint jet clustering algorithm in the rapidity region of |y|<2.1. The results are consistent with next-to-leading-order perturbative QCD predictions based on recent parton distribution functions (PDFs), and are expected to provide increased precision in PDFs at high parton momentum fraction x. The results are also compared to the recent inclusive jet cross section measurement using the kT jet clustering algorithm, and we find that the ratio of the cross sections measured with the two algorithms is in agreement with theoretical expectations over a large range of jet transverse momentum and rapidity.10 MoreReceived 14 July 2008DOI:https://doi.org/10.1103/PhysRevD.78.052006©2008 American Physical Society

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.

In CDF we have observed the reactions p + p[over] --> p + X + p[over], with X being a centrally produced J/psi, psi(2S), or chi_{c0}, and gammagamma-->micro;{+}micro;{-} in pp[over] collisions at sqrt[s] = 1.96 TeV. The event signature requires two oppositely charged central muons, and either no other particles or one additional photon detected. Exclusive vector meson production is as expected for elastic photoproduction, gamma + p --> J/psi(psi(2S)) + p, observed here for the first time in hadron-hadron collisions. We also observe exclusive chi_{c0} --> J/psi + gamma. The cross sections dsigma/dy|_{y = 0} for J/psi, psi(2S), and chi_{c0} are 3.92 +/- 0.25(stat) +/- 0.52(syst) nb, 0.53 +/- 0.09(stat) +/- 0.10(syst) nb, and 76 +/- 10(stat) +/- 10(syst) nb, respectively, and the continuum is consistent with QED. We put an upper limit on the cross section for Odderon exchange in exclusive J/psi production.

We report an indirect search for nonstandard model physics using the flavor-changing neutral current decays B→K(*)μ(+)μ(-). We reconstruct the decays and measure their angular distributions, as a function of q(2)=M(μμ)(2)c(2), where M(μμ) is the dimuon mass, in pp¯ collisions at √s=1.96 TeV using a data sample corresponding to an integrated luminosity of 6.8 fb(-1). The transverse polarization asymmetry A(T)(2) and the time-reversal-odd charge-and-parity asymmetry A(im) are measured for the first time, together with the K* longitudinal polarization fraction F(L) and the muon forward-backward asymmetry A(FB) for the decays B(0)→K(*0)μ(+)μ(-) and B(+)→K(*+)μ(+)μ(-). The B→K*μ(+)μ(-) forward-backward asymmetry in the most sensitive kinematic regime, 1≤q(2)<6 GeV(2)/c(2), is measured to be A(FB)=0.29(-0.23)(+0.20)(stat)±0.07(syst), the most precise result to date. No deviations from the standard model predictions are observed.

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 report the first observation of the baryonic flavor-changing neutral current decay Λ(b)(0)→Λμ(+)μ(-) with 24 signal events and a statistical significance of 5.8 Gaussian standard deviations. This measurement uses a pp collisions data sample corresponding to 6.8 fb(-1) at √s = 1.96 TeV collected by the CDF II detector at the Tevatron collider. The total and differential branching ratios for Λ(b)(0)→Λμ(+)μ(-) are measured. We find B(Λ(b)(0)→Λμ(+)μ(-))=[1.73 ± 0.42(stat) ± (syst)] × 10(-6). We also report the first measurement of the differential branching ratio of B(s)(0)→ϕμ(+)μ(-), using 49 signal events. In addition, we report branching ratios for B(+)→K(+)μ(+)μ(-), B(0)→K(0)μ(+)μ(-), and B→K(*)(892)μ(+)μ(-) decays.

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.

We report on measurements of the inclusive jet production cross section as a function of the jet transverse momentum in pp¯ collisions at s=1.96 TeV, using the kT algorithm and a data sample corresponding to 1.0 fb−1 collected with the Collider Detector at Fermilab in run II. The measurements are carried out in five different jet rapidity regions with |yjet|<2.1 and transverse momentum in the range 54<pTjet<700 GeV/c. Next-to-leading order perturbative QCD predictions are in good agreement with the measured cross sections.4 MoreReceived 29 January 2007Publisher error corrected 25 May 2007DOI:https://doi.org/10.1103/PhysRevD.75.092006©2007 American Physical Society

We report the first measurements of inclusive W and Z cross sections times leptonic branching ratios for pp collisions at square root[s]=1.96 TeV, based on their decays to electrons and muons. The data correspond to an integrated luminosity of 72 pb(-1) recorded with the CDF detector at the Fermilab Tevatron. We test e-mu universality in W decays, and we measure the ratio of leptonic W and Z rates from which the leptonic branching fraction B(W-->lnu) can be extracted as well as an indirect value for the total width of the W and the Cabibbo-Kobayashi-Maskawa matrix element, |V(cs)|.

We present a measurement of the tt[over ] differential cross section with respect to the tt[over ] invariant mass, dsigma/dM_{tt[over ]}, in pp[over ] collisions at sqrt[s]=1.96 TeV using an integrated luminosity of 2.7 fb;{-1} collected by the CDF II experiment. The tt[over ] invariant mass spectrum is sensitive to a variety of exotic particles decaying into tt[over ] pairs. The result is consistent with the standard model expectation, as modeled by PYTHIA with CTEQ5L parton distribution functions.

We report on the first direct search for charged Higgs bosons decaying into c¯s in t¯t events produced by p¯p collisions at √s=1.96 TeV. The search uses a data sample corresponding to an integrated luminosity of 2.2 fb−1 collected by the CDF II detector at Fermilab and looks for a resonance in the invariant mass distribution of two jets in the lepton+jets sample of t¯t candidates. We observe no evidence of charged Higgs bosons in top quark decays. Hence, 95% upper limits on the top quark decay branching ratio are placed at B(t→H+b)< 0.1 to 0.3 for charged Higgs boson masses of 60 to 150 GeV/c2 assuming B(H+→c¯s)=1.0. The upper limits on B(t→H+b) are also used as model-independent limits on the decay branching ratio of top quarks to generic scalar charged bosons beyond the standard model.Received 8 July 2009DOI:https://doi.org/10.1103/PhysRevLett.103.101803©2009 American Physical Society

We present a search for high-mass neutral resonances using dimuon data corresponding to an integrated luminosity of 2.3 fb(-1) collected in pp[over ] collisions at sqrt[s]=1.96 TeV by the CDF II detector at the Fermilab Tevatron. No significant excess above the standard model expectation is observed in the dimuon invariant-mass spectrum. We set 95% confidence level upper limits on sigmaBR(pp-->X-->micromicro), where X is a boson with spin-0, 1, or 2. Using these cross section limits, we determine lower mass limits on sneutrinos in R-parity-violating supersymmetric models, Z' bosons, and Kaluza-Klein gravitons in the Randall-Sundrum model.

We report the observation of electroweak single top quark production in $3.2\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of $p\overline{p}$ collision data collected by the Collider Detector at Fermilab at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$. Candidate events in the $W+\mathrm{\text{jets}}$ topology with a leptonically decaying $W$ boson are classified as signal-like by four parallel analyses based on likelihood functions, matrix elements, neural networks, and boosted decision trees. These results are combined using a super discriminant analysis based on genetically evolved neural networks in order to improve the sensitivity. This combined result is further combined with that of a search for a single top quark signal in an orthogonal sample of events with missing transverse energy plus jets and no charged lepton. We observe a signal consistent with the standard model prediction but inconsistent with the background-only model by 5.0 standard deviations, with a median expected sensitivity in excess of 5.9 standard deviations. We measure a production cross section of ${2.3}_{\ensuremath{-}0.5}^{+0.6}(\mathrm{stat}+\mathrm{sys})\text{ }\text{ }\mathrm{pb}$, extract the value of the Cabibbo-Kobayashi-Maskawa matrix element $|{V}_{tb}|={0.91}_{\ensuremath{-}0.11}^{+0.11}(\mathrm{stat}+\mathrm{sys})\ifmmode\pm\else\textpm\fi{}0.07\text{ }\text{ }(\mathrm{\text{theory}})$, and set a lower limit $|{V}_{tb}|&gt;0.71$ at the 95% C.L., assuming ${m}_{t}=175\text{ }\text{ }\mathrm{GeV}/{c}^{2}$.

We present the first direct measurement of the W production charge asymmetry as a function of the W boson rapidity yW in p¯p collisions at √s=1.96 TeV. We use a sample of W→eν events in data from 1 fb−1 of integrated luminosity collected using the CDF II detector. In the region |yW|<3.0, this measurement is capable of constraining the ratio of up- and down-quark momentum distributions in the proton more directly than in previous measurements of the asymmetry that are functions of the charged-lepton pseudorapidity.Received 15 January 2009DOI:https://doi.org/10.1103/PhysRevLett.102.181801©2009 American Physical Society

We present an analysis of the mass of the X(3872) reconstructed via its decay to J/psi pi+ pi- using 2.4 fb^-1 of integrated luminosity from ppbar collisions at sqrt(s) = 1.96 TeV, collected with the CDF II detector at the Fermilab Tevatron. The possible existence of two nearby mass states is investigated. Within the limits of our experimental resolution the data are consistent with a single state, and having no evidence for two states we set upper limits on the mass difference between two hypothetical states for different assumed ratios of contributions to the observed peak. For equal contributions, the 95% confidence level upper limit on the mass difference is 3.6 MeV/c^2. Under the single-state model the X(3872) mass is measured to be 3871.61 +- 0.16 (stat) +- 0.19 (syst) MeV/c^2, which is the most precise determination to date.

We report the first observation of two narrow resonances consistent with states of orbitally excited (L=1) B_s mesons using 1 fb^{-1} of ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We use two-body decays into K^- and B^+ mesons reconstructed as B^+ \to J/\psi K^+, J/\psi \to \mu^+ \mu^- or B^+ \to \bar{D}^0 \pi^+, \bar{D}^0 \to K^+ \pi^-. We deduce the masses of the two states to be m(B_{s1}) = 5829.4 +- 0.7 MeV/c^2 and m(B_{s2}^*) = 5839.7 +- 0.7 MeV/c^2.

We present the results of searches for large extra dimensions in samples of events with large missing transverse energy ${\mathrm{E\ensuremath{\llap{\not\;}}}}_{T}$ and either a photon or a jet produced in $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ collected with the Collider Detector at Fermilab II. For $\ensuremath{\gamma}+{\mathrm{E\ensuremath{\llap{\not\;}}}}_{T}$ and $\mathrm{\text{jet}}+{\mathrm{E\ensuremath{\llap{\not\;}}}}_{T}$ candidate samples corresponding to 2.0 and $1.1\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity, respectively, we observe good agreement with standard model expectations and obtain a combined lower limit on the fundamental parameter of the large extra dimensions model ${M}_{D}$ as a function of the number of extra dimensions in the model.

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 $200\text{ }\text{ }\mathrm{GeV}/{c}^{2}$.

We present the results of a search for doubly charged Higgs bosons (H+/-+/-) decaying to dileptons (ll(')) using approximately 240 pb(-1) of pp collision data collected by the CDF II experiment at the Fermilab Tevatron. In our search region, given by same-sign ll(') mass m(ll('))>80 GeV/c(2) (100 GeV/c(2) for ee channel), we observe no evidence for H+/-+/- production. We set limits on sigma(pp -->H++H---->l(+)l('+)l(-)l('-)) as a function of the mass of the H+/-+/- and the chirality of its couplings. Assuming exclusive same-sign dilepton decays, we derive lower mass limits on H(+/-+/-)(L) of 133, 136, and 115 GeV/c(2) in the ee, mumu, and emu channels, respectively, and a lower mass limit of 113 GeV/c(2) on H(+/-+/-)(R) in the mumu channel, all at the 95% confidence level.

We measure the masses of $b$ hadrons in exclusively reconstructed final states containing a $J/\psi\to\mu^-\mu^+$ decay using $\rm 220 pb^{-1}$ of data collected by the CDF II experiment. We find: m(B^+) = 5279.10 \pm 0.41_{(stat.)} \pm 0.36_{(sys.)} MeVcc, m(B^0) = 5279.63 \pm 0.53_{(stat.)} \pm 0.33_{(sys.)} MeVcc, m(B^0_s) = 5366.01 \pm 0.73_{(stat.)} \pm 0.33_{(sys.)} MeVcc, m(\Lambda^0_b) = 5619.7 \pm 1.2_{(stat.)} \pm 1.2_{(sys.)} MeVcc. m(B^+) - m(B^0) = -0.53 \pm 0.67_{(stat.)} \pm 0.14_{(sys.)} MeVcc, m(B^0_s) - m(B^0) = 86.38 \pm 0.90_{(stat.)} \pm 0.06_{(sys.)} MeVcc m(\Lambda^0_b) - m(B^0) = 339.2 \pm 1.4_{(stat.)} \pm 0.1_{(sys.)} MeVcc. The measurements of the $B^0_s$, $\Lambda^0_b$ mass, $m(B^0_s)-m(B^0)$ and $m(\Lambda^0_b)-m(B^0)$ mass difference are of better precision than the current world averages.

We present the first observation of exclusive e+e− production in hadron-hadron collisions, using p¯p collision data at √s=1.96 TeV taken by the run II Collider Detector at Fermilab, and corresponding to an integrated luminosity of 532 pb−1. We require the absence of any particle signatures in the detector except for an electron and a positron candidate, each with transverse energy ET>5 GeV and pseudorapidity |η|<2. With these criteria, 16 events are observed compared to a background expectation of 1.9±0.3 events. These events are consistent in cross section and properties with the QED process p¯p→p+e+e−+¯p through two-photon exchange. The measured cross section is 1.6+0.5−0.3(stat)±0.3(syst) pb. This agrees with the theoretical prediction of 1.71±0.01 pb.Received 27 November 2006DOI:https://doi.org/10.1103/PhysRevLett.98.112001©2007 American Physical Society

We report on a search for inclusive production of squarks and gluinos in $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$, in events with large missing transverse energy and multiple jets of hadrons in the final state. The study uses a CDF Run II data sample corresponding to $2\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity. The data are in good agreement with the standard model predictions, giving no evidence for any squark or gluino component. In an $R$-parity conserving minimal supergravity scenario with ${A}_{0}=0$, $\ensuremath{\mu}&lt;0$, and $\mathrm{tan}\ensuremath{\beta}=5$, 95% C.L. upper limits on the production cross sections in the range between 0.1 and 1 pb are obtained, depending on the squark and gluino masses considered. For gluino masses below $280\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, arbitrarily large squark masses are excluded at the 95% C.L., while for mass degenerate gluinos and squarks, masses below $392\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ are excluded at the 95% C.L.

We report the most restrictive direct limits on masses of fourth-generation down-type quarks b′, and quarklike composite fermions (B or T5/3), decaying promptly to tW∓. We search for a significant excess of events with two same-charge leptons (e, μ), several hadronic jets, and missing transverse energy. An analysis of data from p¯p collisions with an integrated luminosity of 2.7 fb−1 collected with the CDF II detector at Fermilab yields no evidence for such a signal, setting mass limits mb′, mB>338 GeV/c2 and mT5/3>365 GeV/c2 at 95% confidence level.Received 5 December 2009DOI:https://doi.org/10.1103/PhysRevLett.104.091801©2010 American Physical Society

We report a set of measurements of particle production in inelastic p¯p collisions collected with a minimum-bias trigger at the Tevatron Collider with the CDF II experiment. The inclusive charged particle transverse momentum differential cross section is measured, with improved precision, over a range about ten times wider than in previous measurements. The former modeling of the spectrum appears to be incompatible with the high particle momenta observed. The dependence of the charged particle transverse momentum on the event particle multiplicity is analyzed to study the various components of hadron interactions. This is one of the observable variables most poorly reproduced by the available Monte Carlo generators. A first measurement of the event transverse energy sum differential cross section is also reported. A comparison with a pythia prediction at the hadron level is performed. The inclusive charged-particle differential production cross section is fairly well reproduced only in the transverse momentum range available from previous measurements. At higher momentum the agreement is poor. The transverse energy sum is poorly reproduced over the whole spectrum. The dependence of the charged particle transverse momentum on the particle multiplicity needs the introduction of more sophisticated particle production mechanisms, such as multiple parton interactions, in order to be better explained.3 MoreReceived 8 April 2009DOI:https://doi.org/10.1103/PhysRevD.79.112005©2009 American Physical Society

Data collected in run II of the Fermilab Tevatron are searched for indications of new electroweak-scale physics. Rather than focusing on particular new physics scenarios, CDF data are analyzed for discrepancies with the standard model prediction. A model-independent approach (Vista) considers gross features of the data, and is sensitive to new large cross-section physics. Further sensitivity to new physics is provided by two additional algorithms: a Bump Hunter searches invariant mass distributions for ``bumps'' that could indicate resonant production of new particles, and the Sleuth procedure scans for data excesses at large summed transverse momentum. This combined global search for new physics in $2.0\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ reveals no indication of physics beyond the standard model.

A search for high-mass resonances in the ${e}^{+}{e}^{\ensuremath{-}}$ final state is presented based on $2.5\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ $p\overline{p}$ collision data from the CDF II detector at the Fermilab Tevatron. The largest excess over the standard model prediction is at an ${e}^{+}{e}^{\ensuremath{-}}$ invariant mass of $240\text{ }\text{ }\mathrm{GeV}/{c}^{2}$. The probability of observing such an excess arising from fluctuations in the standard model anywhere in the mass range of $150--1000\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ is 0.6% (equivalent to $2.5\ensuremath{\sigma}$). We exclude the standard model coupling ${Z}^{\ensuremath{'}}$ and the Randall-Sundrum graviton for $k/{\overline{M}}_{\mathrm{Pl}}=0.1$ with masses below 963 and $848\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ at the 95% credibility level, respectively.

We report a search for the flavor changing neutral current (FCNC) decay of the top quark \tZq ($q=u,c$) in \ppbar collisions at $\sqrt{s} = 1.96\tev$ using a data sample corresponding to an integrated luminosity of 1.9\invfb collected by the CDF II detector. This decay is strongly suppressed in the standard model (SM) and an observation of a signal at the Tevatron would be an indication of physics beyond the SM. Using $Z+\ge4$ jet final state candidate events, both with and without an identified bottom quark jet, we discriminate signal from background by exploiting kinematic constraints present in FCNC events and obtain an upper limit of $\btZq < 3.7%$ at 95% C.L.

We performed a signature-based search for long-lived charged massive particles produced in $1.0\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$, collected with the CDF II detector using a high transverse-momentum (${p}_{T}$) muon trigger. The search used time of flight to isolate slowly moving, high-${p}_{T}$ particles. One event passed our selection cuts with an expected background of $1.9\ifmmode\pm\else\textpm\fi{}0.2$ events. We set an upper bound on the production cross section and, interpreting this result within the context of a stable scalar top-quark model, set a lower limit on the particle mass of $249\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ at 95% C.L.

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 report the observation of the bottom, doubly-strange baryon Omega^-_b through the decay chain Omega^-_b -> J/psi Omega^-, where J/psi -> mu^+ mu^-, Omega^- -> Lambda K^-, and Lambda -> p pi^-, using 4.2 fb^{-1} of data from p\bar p collisions at sqrt{s}=1.96 TeV, and recorded with the Collider Detector at Fermilab. A signal is observed whose probability of arising from a background fluctuation is 4.0 * 10^{-8}, or 5.5 Gaussian standard deviations. The Omega^-_b mass is measured to be 6054.4 +/- 6.8 (stat.) +/- 0.9 (syst.) MeV/c^2. The lifetime of the Omega^-_b baryon is measured to be 1.13^{+0.53}_{-0.40}(stat.) +/- 0.02(syst.)$ ps. In addition, for the \Xi^-_b baryon we measure a mass of 5790.9 +/- 2.6(stat.) +/- 0.8(syst.) MeV/c^2 and a lifetime of 1.56^{+0.27}_{-0.25}(stat.) +/-0.02(syst.) ps. Under the assumption that the \Xi_b^- and \Omega_b^- are produced with similar kinematic distributions to the \Lambda^0_b baryon, we find sigma(Xi_b^-) B(Xi_b^- -> J/psi Xi^-)}/ sigma(Lambda^0_b) B(Lambda^0_b -> J/psi Lambda)} = 0.167^{+0.037}_{-0.025}(stat.) +/-0.012(syst.) and sigma(Omega_b^-) B(Omega_b^- -> J/psi Omega^-)/ sigma(Lambda^0_b) B(Lambda^0_b -> J/psi Lambda)} = 0.045^{+0.017}_{-0.012}(stat.) +/- 0.004(syst.) for baryons produced with transverse momentum in the range of 6-20 GeV/c.

We report a measurement of the ratio of the tt to Z/γ{*} production cross sections in sqrt[s]=1.96 TeV pp collisions using data corresponding to an integrated luminosity of up to 4.6 fb{-1}, collected by the CDF II detector. The tt cross section ratio is measured using two complementary methods, a b-jet tagging measurement and a topological approach. By multiplying the ratios by the well-known theoretical Z/γ{*}→ll cross section predicted by the standard model, the extracted tt cross sections are effectively insensitive to the uncertainty on luminosity. A best linear unbiased estimate is used to combine both measurements with the result σ{tt}=7.70±0.52 pb, for a top-quark mass of 172.5 GeV/c{2}.

We study the underlying event in proton-antiproton collisions by examining the behavior of charged particles produced in association with a large transverse momentum jet ($\ensuremath{\sim}2.2\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$) or with a Drell-Yan lepton pair ($\ensuremath{\sim}2.7\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$) in the $Z$-boson mass region [$70&lt;M(\mathrm{\text{pair}})&lt;110\text{ }\text{ }\mathrm{GeV}/{c}^{2}$] as measured by CDF at 1.96 TeV center-of-mass energy. We use the direction of the lepton pair or the leading jet in each event to define regions of $\ensuremath{\eta}\mathrm{\text{\ensuremath{-}}}\ensuremath{\phi}$ space that are sensitive to the modeling of the underlying event. The data are corrected to the particle level to remove detector effects and are then compared with several QCD Monte Carlo models.

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}.$

This Letter describes the current most precise measurement of the $W$ boson pair production cross section and most sensitive test of anomalous $WW\ensuremath{\gamma}$ and $WWZ$ couplings in $p\overline{p}$ collisions at a center-of-mass energy of 1.96 TeV. The $WW$ candidates are reconstructed from decays containing two charged leptons and two neutrinos. Using data collected by the CDF II detector from $3.6\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity, a total of 654 candidate events are observed with an expected background of $320\ifmmode\pm\else\textpm\fi{}47$ events. The measured cross section is $\ensuremath{\sigma}(p\overline{p}\ensuremath{\rightarrow}{W}^{+}{W}^{\ensuremath{-}}+X)=12.1\ifmmode\pm\else\textpm\fi{}0.9(\mathrm{stat}{)}_{\ensuremath{-}1.4}^{+1.6}(\mathrm{syst})\text{ }\text{ }\mathrm{pb}$, which is in good agreement with the standard model prediction. The same data sample is used to place constraints on anomalous $WW\ensuremath{\gamma}$ and $WWZ$ couplings.

The cross section for jets from b quarks produced with a W boson has been measured in pp collision data from 1.9 fb(-1) of integrated luminosity recorded by the CDF II detector at the Tevatron. The W+b-jets process poses a significant background in measurements of top quark production and prominent searches for the Higgs boson. We measure a b-jet cross section of 2.74+/-0.27(stat)+/-0.42(syst) pb in association with a single flavor of leptonic W boson decay over a limited kinematic phase space. This measured result cannot be accommodated in several available theoretical predictions.

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.

We report on a study of jet shapes in inclusive jet production in p¯p collisions at √s=1.96 TeV using the upgraded collider detector at Fermilab in Run II (CDF II) and based on an integrated luminosity of 170 pb−1. Measurements are carried out on jets with rapidity 0.1<|Yjet|<0.7 and transverse momentum 37 GeV/c<PjetT<380 GeV/c. The jets have been corrected to the hadron level. The measured jet shapes are compared to leading-order QCD parton-shower Monte Carlo predictions as implemented in the PYTHIA and HERWIG programs. PYTHIA, tuned to describe the underlying event as measured in CDF Run I, provides a better description of the measured jet shapes than does PYTHIA or HERWIG with their default parameters.2 MoreReceived 9 May 2005DOI:https://doi.org/10.1103/PhysRevD.71.112002©2005 American Physical Society

We report a measurement of the forward-backward charge asymmetry of electrons from W boson decays in p anti-p collisions at s**(1/2) = 1.96 TeV using a data sample of 170 pb-1 collected by the Collider Detector at Fermilab. The asymmetry is measured as a function of electron rapidity and transverse energy and provides new input on the momentum fraction dependence of the u and d quark parton distribution within the proton.

We describe a measurement of the W boson mass mW using 200/pb of root-s = 1.96 TeV p-pbar collision data taken with the CDF II detector. With a sample of 63,964 W -> e nu candidates and 51,128 W -> mu nu candidates, we measure mW = [80.413 +- 0.034 (stat) +- 0.034 (sys) = 80.413 +- 0.048] GeV/c^2. This is the single most precise mW measurement to date. When combined with other measured electroweak parameters, this result further constrains the properties of unobserved particles coupling to W and Z bosons.

We use the three lepton and missing energy trilepton signature to search for chargino-neutralino production with 2.0 fb−1 of integrated luminosity collected by the CDF II experiment at the Tevatron p¯p collider. We expect an excess of approximately 11 supersymmetric events for a choice of parameters of the mSUGRA model, but our observation of 7 events is consistent with the standard model expectation of 6.4 events. We constrain the mSUGRA model of supersymmetry and rule out chargino masses up to 145 GeV/c2 for a specific choice of parameters.Received 19 August 2008DOI:https://doi.org/10.1103/PhysRevLett.101.251801©2008 American Physical Society

This Letter presents a search for exclusive $Z$ boson production in proton-antiproton collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$, using the CDF II detector. No exclusive $Z\ensuremath{\rightarrow}{l}^{+}{l}^{\ensuremath{-}}$ candidates are observed and the first upper limit on the exclusive $Z$ cross section in hadron collisions is found to be ${\ensuremath{\sigma}}_{\mathrm{excl}}(Z)&lt;0.96\text{ }\text{ }\mathrm{pb}$ at 95% confidence level. In addition, eight candidate exclusive dilepton events from the process $p\overline{p}\ensuremath{\rightarrow}p\ensuremath{\gamma}\ensuremath{\gamma}\overline{p}\ensuremath{\rightarrow}p{l}^{+}{l}^{\ensuremath{-}}\overline{p}$ are observed, and a measurement of the cross section for ${M}_{ll}&gt;40\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ and $|{\ensuremath{\eta}}_{l}|&lt;4$ is found to be $\ensuremath{\sigma}={0.24}_{\ensuremath{-}0.10}^{+0.13}\text{ }\text{ }\mathrm{pb}$, which is consistent with the standard model prediction.

We report on the first search for top-quark production via flavor-changing neutral-current (FCNC) interactions in the non-standard-model process u(c)+g -> t using ppbar collision data collected by the CDF II detector. The data set corresponds to an integrated luminosity of 2.2/fb. The candidate events feature the signature of semileptonic top-quark decays and are classified as signal-like or background-like by an artificial neural network trained on simulated events. The observed discriminant distribution is in good agreement with the one predicted by the standard model and provides no evidence for FCNC top-quark production, resulting in a Bayesian upper limit on the production cross section sigma (u(c)+g -> t) < 1.8 pb at the 95% confidence level. Using theoretical predictions we convert the cross-section limit to upper limits on FCNC branching ratios: BR (t -> u+g) < 3.9 x 10{-4}$ and BR (t -> c+g) < 5.7 x 10^{-3}.

We present new limits on resonant tb[over] production in pp[over] collisions at sqrt[s] = 1.96 TeV, using 1.9 fb;{-1} of data recorded with the CDF II detector at the Fermilab Tevatron. We reconstruct a candidate tb[over] mass in events with a lepton, neutrino candidate, and two or three jets, and search for anomalous tb[over] production as modeled by W;{'} --> tb[over]. We set a new limit on a right-handed W;{'} with standard model-like coupling, excluding any mass below 800 GeV/c;{2} at 95% C.L. The cross section for any narrow, resonant tb[over] production between 750 and 950 GeV/c;{2} is found to be less than 0.28 pb at 95% C.L. We also present an exclusion of the W;{'} coupling strength versus W;{'} mass over the range 300-950 GeV/c;{2}.

We report a measurement of the top-quark mass ${M}_{t}$ in the dilepton decay channel $t\overline{t}\ensuremath{\rightarrow}b{l}^{\ensuremath{'}+}{\ensuremath{\nu}}_{l}^{\ensuremath{'}}\overline{b}{l}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{l}$. Events are selected with a neural network which has been directly optimized for statistical precision in top-quark mass using neuroevolution, a technique modeled on biological evolution. The top-quark mass is extracted from per-event probability densities that are formed by the convolution of leading order matrix elements and detector resolution functions. The joint probability is the product of the probability densities from 344 candidate events in $2.0\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of $p\overline{p}$ collisions collected with the CDF II detector, yielding a measurement of ${M}_{t}=171.2\ifmmode\pm\else\textpm\fi{}2.7(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}2.9(\mathrm{syst})\text{ }\text{ }\mathrm{GeV}/{c}^{2}$.

We report a measurement of the single-top-quark production cross section in $2.2\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of $p\overline{p}$ collision data collected by the Collider Detector at Fermilab at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$. Candidate events are classified as signal-like by three parallel analyses which use likelihood, matrix element, and neural network discriminants. These results are combined in order to improve the sensitivity. We observe a signal consistent with the standard model prediction, but inconsistent with the background-only model by 3.7 standard deviations with a median expected sensitivity of 4.9 standard deviations. We measure a cross section of ${2.2}_{\ensuremath{-}0.6}^{+0.7}(\mathrm{stat}+\mathrm{syst})\text{ }\text{ }\mathrm{pb}$, extract the Cabibbo-Kobayashi-Maskawa matrix-element value $|{V}_{tb}|={0.88}_{\ensuremath{-}0.12}^{+0.13}(\mathrm{stat}+\mathrm{syst})\ifmmode\pm\else\textpm\fi{}0.07(\mathrm{theory})$, and set the limit $|{V}_{tb}|&gt;0.66$ at the 95% C.L.

Data collected in run II of the Fermilab Tevatron are searched for indications of new electroweak scale physics. Rather than focusing on particular new physics scenarios, CDF data are analyzed for discrepancies with respect to the standard model prediction. A model-independent approach (Vista) considers the gross features of the data and is sensitive to new large cross section physics. A quasi-model-independent approach (Sleuth) searches for a significant excess of events with large summed transverse momentum and is particularly sensitive to new electroweak scale physics that appears predominantly in one final state. This global search for new physics in over 300 exclusive final states in $927\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$ of $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ reveals no such significant indication of physics beyond the standard model.

We reconstruct the rare decays B(+)→K(+)μ(+0μ(-0, B90)→K*(892)(0)μ(+)μ(-), and B(s)(0)→ϕ(1020)μ(+)μ(-) in a data sample corresponding to 4.4 fb(-1) collected in pp collisions at √[s]=1.96 TeV by the CDF II detector at the Tevatron Collider. Using 121±16 B(+)→K(+)μ(+)μ(-) and 101±12 B(0)→K(*0)μ(+)μ(-) decays we report the branching ratios. In addition, we report the differential branching ratio and the muon forward-backward asymmetry in the B(+) and B(0) decay modes, and the K(*0) longitudinal polarization fraction in the B(0) decay mode with respect to the squared dimuon mass. These are consistent with the predictions, and most recent determinations from other experiments and of comparable accuracy. We also report the first observation of the B(s)(0)→ϕμ(+)μ(-) decay and measure its branching ratio BR(B(s)(0)→ϕμ(+)μ(-))=[1.44±0.33±0.46]×10(-6) using 27±6 signal events. This is currently the most rare B(s)(0) decay observed.

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.

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.

We report a measurement of the ttbar production cross section using dilepton events with jets and missing transverse energy in ppbar collisions at a center-of-mass energy of 1.96 TeV. Using a 197 +/- 12 pb-1 data sample recorded by the upgraded Collider Detector at Fermilab, we use two complementary techniques to select candidate events. We compare the number of observed events and selected kinematical distributions with the predictions of the Standard Model and find good agreement. The combined result of the two techniques yields a ttbar production cross section of 7.0 +2.4/-2.1(stat.) +1.6/-1.1(syst.) +/- 0.4(lum.) pb.

We report on a search for B(0)(s)-->micro(+)micro(-) and B(0)(d)-->micro(+)micro(-) decays in pp collisions at square root of s=1.96 TeV using 171 pb(-1) of data collected by the CDF II experiment at the Fermilab Tevatron Collider. The decay rates of these rare processes are sensitive to contributions from physics beyond the standard model. One event survives all our selection requirements, consistent with the background expectation. We derive branching ratio limits of B(B(0)(s)-->micro(+)micro(-))<5.8x10(-7) and B(B(0)(d)-->micro(+)micro(-))<1.5x10(-7) at 90% confidence level.

We present measurements of the lifetimes and polarization amplitudes for B(0)(s)-->J/psiphi and B(0)(d)-->J/psiK(*0) decays. Lifetimes of the heavy and light mass eigenstates in the B(0)(s) system are separately measured for the first time by determining the relative contributions of amplitudes with definite CP as a function of the decay time. Using 203+/-15 B(0)(s) decays we obtain tau(L) = (1.05(+0.16)(-0.13) +/- 0.02) ps and tau(H) = (2.07(+0.58)(-0.46) +/- 0.03) ps. Expressed in terms of the difference DeltaGamma(s) and average Gamma(s), of the decay rates of the two eigenstates, the results are DeltaGamma(s)/Gamma(s) = (65(+25)(-33) +/- 1)% and DeltaGamma(s) = (0.47(+0.19)(-0.24) +/- 0.01) ps(-1).

We measure the ratio of cross section times branching fraction, Rp=sigma chi c2 B(chi c2-->J/psi gamma)/sigma chi c1 B(chi c1-->J/psi gamma), in 1.1 fb(-1) of pp collisions at square root s=1.96 TeV. This measurement covers the kinematic range pT(J/psi)>4.0 GeV/c, |eta(J/psi)<1.0, and pT(gamma)>1.0 GeV/c. For events due to prompt processes, we find Rp=0.395+/-0.016(stat)+/-0.015(syst). This result represents a significant improvement in precision over previous measurements of prompt chi c1,2 hadro production.

We measure the mean lifetime tau=2/(Gamma_{L}+Gamma_{H}) and the decay-width difference DeltaGamma=Gamma_{L}-Gamma_{H} of the light and heavy mass eigenstates of the B_{s}{0} meson, B_{sL}{0} and B_{sH}{0}, in B_{s}{0}-->J/psivarphi decays using 1.7 fb;{-1} of data collected with the CDF II detector at the Fermilab Tevatron pp[over ] collider. Assuming CP conservation, a good approximation for the B_{s}{0} system in the standard model, we obtain DeltaGamma=0.076_{-0.063}{+0.059}(stat)+/-0.006(syst) ps{-1} and tau=1.52+/-0.04(stat)+/-0.02(syst) ps, the most precise measurements to date. Our constraints on the weak phase and DeltaGamma are consistent with CP conservation.

We search for new charmless decays of neutral b-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 report the first observation of the B0s-&gt;K-pi+ decay, with a significance of 8.2 sigma, and measure BR(B0s-&gt;K-pi+)= (5.0+-0.7(stat)+-0.8(syst))*10^{-6}. We also report the first observation of charmless b-baryon decays in the channels Lambda_b -&gt; p pi and Lambda_b -&gt; pK with significances of 6.0 sigma and 11.5 sigma respectively, and we measure BR(Lambda_b-&gt;p pi-) = (3.5+-0.6(stat)+-0.9(syst))*10^{-6} and BR(Lambda_b-&gt;p K-) = (5.6+-0.8(stat)+-1.5(syst))*10^{-6}. No evidence is found for the decays B0-&gt;K+K- and B0s -&gt; pi+pi-, and we set an improved upper limit BR(B0s -&gt; pi+pi-) &lt; 1.2*10^{-6}$ at the 90% confidence level. All quoted branching fractions are measured using BR(B0-&gt;K+pi-)$ as a reference.

We describe a search for anomalous production of events with two leptons (e or mu) of the same electric charge in pp[over ] collisions at a center-of-mass energy of 1.96 TeV. Many extensions to the standard model predict the production of two leptons of the same electric charge. This search has a significant increase in sensitivity compared to earlier searches. Using a data sample corresponding to 1 fb(-1) of integrated luminosity recorded by the CDF II detector, we observe no significant excess in an inclusive selection (expect 33.2+/-4.7 events, observe 44) or in a supersymmetry-optimized selection (expect 7.8+/-1.1 events, observe 13.).

A measurement of the cross section for the inclusive production of isolated photons by the CDF experiment at the Fermilab Tevatron collider is presented. The measurement covers the pseudorapidity region |ηγ|<1.0 and the transverse energy range EγT>30 GeV and is based on 2.5 fb−1 of integrated luminosity. The sample is almost a factor of 7 larger than those used for recent published results and extends the EγT coverage by 100 GeV. The result agrees with next-to-leading order perturbative QCD calculations within uncertainties over the range 50<EγT<400 GeV, though the energy spectrum in the data shows a steeper slope at lower EγT.Received 20 October 2009DOI:https://doi.org/10.1103/PhysRevD.80.111106©2009 American Physical Society

We report on a search for narrow-width particles decaying to a top and antitop quark pair. The data set used in the analysis corresponds to an integrated luminosity of 680 pb^{-1} collected with the Collider Detector at Fermilab in Run II. We present 95% confidence level upper limits on the cross section times branching ratio. Assuming a specific topcolor-assisted technicolor production model, the leptophobic Z' with width \Gamma_{Z'}=0.012M_{Z'}, we exclude the mass range M_{Z'} < 725 GeV/c^2 at the 95% confidence level.

We present a search for standard model (SM) Higgs boson production using ppbar collision data at sqrt(s) = 1.96 TeV, collected with the CDF II detector and corresponding to an integrated luminosity of 4.8 fb-1. We search for Higgs bosons produced in all processes with a significant production rate and decaying to two W bosons. We find no evidence for SM Higgs boson production and place upper limits at the 95% confidence level on the SM production cross section (sigma(H)) for values of the Higgs boson mass (m_H) in the range from 110 to 200 GeV. These limits are the most stringent for m_H > 130 GeV and are 1.29 above the predicted value of sigma(H) for mH = 165 GeV.

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.

We present the results of a search for pair production of a heavy toplike (t') quark decaying to Wq final states using data corresponding to an integrated luminosity of 5.6 fb(-1) collected by the CDF II detector in pp collisions at √s=1.96 TeV. We perform parallel searches for t'→Wb and t'→Wq (where q is a generic down-type quark) in events containing a lepton and four or more jets. By performing a fit to the two-dimensional distribution of total transverse energy versus reconstructed t' quark mass, we set upper limits on the t't' production cross section and exclude a standard model fourth-generation t' quark decaying to Wb (Wq) with mass below 358 (340) GeV/c(2) at 95% C.L.

We report a measurement of resonance parameters of the orbitally excited ($L=1$) narrow ${B}^{0}$ mesons in decays to ${B}^{(*)+}{\ensuremath{\pi}}^{\ensuremath{-}}$ using $1.7\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of data collected by the CDF II detector at the Fermilab Tevatron. The mass and width of the ${B}_{2}^{*0}$ state are measured to be $m({B}_{2}^{*0})={5740.2}_{\ensuremath{-}1.8}^{+1.7}(\mathrm{stat}{)}_{\ensuremath{-}0.8}^{+0.9}(\mathrm{syst})\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ and $\ensuremath{\Gamma}({B}_{2}^{*0})={22.7}_{\ensuremath{-}3.2}^{+3.8}(\mathrm{stat}{)}_{\ensuremath{-}10.2}^{+3.2}(\mathrm{syst})\text{ }\text{ }\mathrm{MeV}/{c}^{2}$. The mass difference between the ${B}_{2}^{*0}$ and ${B}_{1}^{0}$ states is measured to be ${14.9}_{\ensuremath{-}2.5}^{+2.2}(\mathrm{stat}{)}_{\ensuremath{-}1.4}^{+1.2}(\mathrm{syst})\text{ }\text{ }\mathrm{MeV}/{c}^{2}$, resulting in a ${B}_{1}^{0}$ mass of ${5725.3}_{\ensuremath{-}2.2}^{+1.6}(\mathrm{stat}{)}_{\ensuremath{-}1.5}^{+1.4}(\mathrm{syst})\text{ }\text{ }\mathrm{MeV}/{c}^{2}$. This is currently the most precise measurement of the masses of these states and the first measurement of the ${B}_{2}^{*0}$ width.

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 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 present a measurement of the ratio of top-quark branching fractions R=B(t→Wb)/B(t→Wq), where q can be a b, s, or a d quark, using lepton-plus-jets and dilepton data sets with an integrated luminosity of ∼162 pb−1 collected with the Collider Detector at Fermilab during Run II of the Tevatron. The measurement is derived from the relative numbers of t¯t events with different multiplicity of identified secondary vertices. We set a lower limit of R>0.61 at 95% confidence level.Received 27 May 2005DOI:https://doi.org/10.1103/PhysRevLett.95.102002©2005 American Physical Society

We present the results of a search for Higgs bosons predicted in two-Higgs-doublet models, in the case where the Higgs bosons decay to tau lepton pairs, using $1.8\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity of $p\overline{p}$ collisions recorded by the CDF II experiment at the Fermilab Tevatron. Studying the mass distribution in events where one or both tau leptons decay leptonically, no evidence for a Higgs boson signal is observed. The result is used to infer exclusion limits in the two-dimensional space of $\mathrm{tan}\ensuremath{\beta}$ versus ${m}_{A}$ (the ratio of the vacuum expectation values of the two Higgs doublets and the mass of the pseudoscalar boson, respectively).

We report the first observation of the associated production of a $W$ boson and a $Z$ boson. This result is based on $1.1\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ 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. We observe 16 $WZ$ candidates passing our event selection with an expected background of $2.7\ifmmode\pm\else\textpm\fi{}0.4$ events. A fit to the missing transverse energy distribution indicates an excess of events compared to the background expectation corresponding to a significance equivalent to 6 standard deviations. The measured cross section is $\ensuremath{\sigma}(p\overline{p}\ensuremath{\rightarrow}WZ)={5.0}_{\ensuremath{-}1.6}^{+1.8}\text{ }\text{ }\mathrm{pb}$, consistent with the standard model expectation.

We present the results of a search for supersymmetry with gauge-mediated breaking and $\NONE\to\gamma\Gravitino$ in the $\gamma\gamma$+missing transverse energy final state. In 2.6$\pm$0.2 \invfb of $p{\bar p}$ collisions at $\sqrt{s}$$=$1.96 TeV recorded by the CDF II detector we observe no candidate events, consistent with a standard model background expectation of 1.4$\pm$0.4 events. We set limits on the cross section at the 95% C.L. and place the world's best limit of 149\gevc on the \none mass at $\tau_{\tilde{\chi}_1^0}$$<<$1 ns. We also exclude regions in the \none\ mass-lifetime plane for $\tau_{\tilde{\chi}_1^0}$$\lesssim$2 ns.

A measurement of the b jet production cross section is presented for events containing a Z boson produced in p¯p collisions at √s=1.96 TeV, using data corresponding to an integrated luminosity of 2 fb−1 collected by the CDF II detector at the Tevatron. Z bosons are selected in the electron and muon decay modes. Jets are considered with transverse energy ET>20 GeV and pseudorapidity |η|<1.5 and are identified as b jets using a secondary vertex algorithm. The ratio of the integrated Z+b jet cross section to the inclusive Z production cross section is measured to be 3.32±0.53(stat)±0.42(syst)×10−3. This ratio is also measured differentially in jet ET, jet η, Z-boson transverse momentum, number of jets, and number of b jets. The predictions from leading-order Monte Carlo generators and next-to-leading-order QCD calculations are found to be consistent with the measurements within experimental and theoretical uncertainties.2 MoreReceived 21 January 2009DOI:https://doi.org/10.1103/PhysRevD.79.052008©2009 American Physical Society

We report results from a search for the lepton flavor violating decays B_{s};{0} --> e;{+} micro;{-} and B;{0} --> e;{+} micro;{-}, and the flavor-changing neutral-current decays B_{s};{0} --> e;{+} e;{-} and B;{0} --> e;{+} e;{-}. The analysis uses data corresponding to 2 fb;{-1} of integrated luminosity of pp[over ] collisions at sqrt[s] = 1.96 TeV collected with the upgraded Collider Detector (CDF II) at the Fermilab Tevatron. The observed number of B0 and B_{s};{0} candidates is consistent with background expectations. The resulting Bayesian upper limits on the branching ratios at 90% credibility level are B(B_{s};{0} --> e;{+} micro;{-}) < 2.0 x 10;{-7}, B(B;{0} --> e;{+} micro;{-}) < 6.4 x 10;{-8}, B(B_{s};{0} --> e;{+} e;{-}) < 2.8 x 10;{-7}, and B(B;{0} --> e;{+} e;{-}) < 8.3 x 10;{-8}. From the limits on B(B_{(s)};{0} --> e;{+} micro;{-}), the following lower bounds on the Pati-Salam leptoquark masses are also derived: M_{LQ}(B_{s};{0} --> e;{+} micro;{-}) > 47.8 TeV/c;{2}, and M_{LQ}(B;{0} --> e;{+} micro;{-}) > 59.3 TeV / c;{2}, at 90% credibility level.

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.

We report on a measurement of b-hadron lifetimes in the fully reconstructed decay modes B(+)→J/ψK(+), B⁰→J/ψK*(892)⁰, B⁰→J/ψK(s)⁰, and Λ(b)⁰→J/ψΛ⁰ using data corresponding to an integrated luminosity of 4.3 fb⁻¹, collected by the CDF II detector at the Fermilab Tevatron. The measured lifetimes are τ(B(+))=[1.639±0.009(stat)±0.009(syst)] ps, τ(B⁰)=[1.507±0.010(stat)±0.008(syst)] ps, and τ(Λ(b)⁰)=[1.537±0.045(stat)±0.014(syst)] ps. The lifetime ratios are τ(B(+))/τ(B⁰)=[1.088±0.009(stat)±0.004(syst)] and τ(Λ(b)⁰)/τ(B⁰)=[1.020±0.030(stat)±0.008(syst)]. These are the most precise determinations of these quantities from a single experiment.

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 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 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.