A. Beretvas

We establish the existence of the top quark using a 67 pb^-1 data sample of Pbar-P collisions at Sqrt(s) = 1.8 TeV collected with the Collider Detector at Fermilab (CDF). Employing techniques similar to those we previously published, we observe a signal consistent with t-tbar decay to WW b-bbar, but inconsistent with the background prediction by 4.8 sigma. Additional evidence for the top quark is provided by a peak in the reconstructed mass distribution. We measure the top quark mass to be 176 +/-8(stat) +/- 10(sys.) GeV/c^2, and the t-tbar production cross section to be 6.8 +3.6 -2.4 pb.

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.

The Collider Detector at Fermilab (CDF) is a 5000 t magnetic detector built to study 2 TeV pp collisions at the Fermilab Tevatron. Event analysis is based on charged particle tracking, magnetic momentum analysis and fine-grained calorimetry. The combined electromagnetic and hadron calorimetry has approximately uniform granularity in rapidity-azimuthal angle and extends down to 2° from the beam direction. Various tracking chambers cover the calorimeter acceptance and extend charged particle tracking down to 2 mrad from the beam direction. Charged particle momenta are analyzed in a 1.5 T solenoidal magnetic field, generated by a superconducting coil which is 3 m in diameter and 5 m in length. The central tracking chamber measures particle momenta with a resolution better then δpT/pT2 = 2 × 10−3 (GeV/c)−1 in the region 40° < θ < 140° and δPT/pT2 ≤ 4 × 10−3 for 21° < θ < 40° and 140° < θ < 159°. The calorimetry, which has polar angle coverage from 2° to 178° and full azimuthal coverage, consists of electromagnetic shower counters and hadron calorimeters, and is segmented into about 5000 projective “towers” or solid angle elements. Muon coverage is provided by drift chambers in the region 56° < θ < 124°, and by large forward toroid systems in the range 3° < θ < 16° and 164° < θ < 177°. Isolated high momentum muons can be identified in the intermediate angular range by a comparison of the tracking and calorimeter information in many cases. A custom front-end electronics system followed by a large Fastbus network provides the readout of the approximately 100 000 detector channels. Fast Level 1 and Level 2 triggers make a detailed pre-analysis of calorimetry and tracking information; a Level 3 system of on-line processors will do parallel processing of events. This paper provides a summary of the aspects of the detector which are relevant to its physics capabilities, with references to more detailed descriptions of the subsystems.

We present the results of a search for the top quark in 19.3 pb−1 of p¯p collisions at √s =1.8 TeV. The data were collected at the Fermilab Tevatron collider using the Collider Detector at Fermilab (CDF). The search includes standard model tt¯ decays to final states eeνν¯, eμνν¯, and μμνν¯ as well as e+ν+jets or μ+ν+jets. In the (e,μ)+ν+jets channel we search for b quarks from t decays via secondary vertex identification and via semileptonic decays of the b and cascade c quarks. In the dilepton final states we find two events with a background of 0.56+0.25−0.13 events. In the e,μ+ν+jets channel with a b identified via a secondary vertex, we find six events with a background of 2.3±0.3. With a b identified via a semileptonic decay, we find seven events with a background of 3.1±0.3. The secondary vertex and semileptonic-decay samples have three events in common. The probability that the observed yield is consistent with the background is estimated to be 0.26%. The statistics are too limited to firmly establish the existence of the top quark; however, a natural interpretation of the excess is that it is due to tt¯ production. We present several cross-checks. Some support this hypothesis; others do not. Under the assumption that the excess yield over background is due to tt¯, constrained fitting on a subset of the events yields a mass of 174±10+13−12 GeV/c2 for the top quark. The tt¯ cross section, using this top quark mass to compute the acceptance, is measured to be 13.9+6.1−4.8 pb.Received 25 April 1994DOI:https://doi.org/10.1103/PhysRevD.50.2966©1994 American Physical Society

We summarize a search for the top quark with the Collider Detector at Fermilab (CDF) in a sample of $\bar{p}p$ collisions at $\sqrt{s}$= 1.8 TeV with an integrated luminosity of 19.3~pb$^{-1}$. We find 12 events consistent with either two $W$ bosons, or a $W$ boson and at least one $b$ jet. The probability that the measured yield is consistent with the background is 0.26%. Though the statistics are too limited to establish firmly the existence of the top quark, a natural interpretation of the excess is that it is due to $t\bar{t}$ production. Under this assumption, constrained fits to individual events yield a top quark mass of $174 \pm 10^{+13}_{-12}$ GeV/c$^2$. The $t\bar{t}$ production cross section is measured to be $13.9^{+6.1}_{-4.8}$~pb. (Submitted to Physical Review Letters on May 16, 1994).

We report the observation of B0s−¯¯¯B0s oscillations from a time-dependent measurement of the B0s−¯¯¯B0s oscillation frequency Δms. Using a data sample of 1 fb−1 of p¯p collisions at √s=1.96 TeV collected with the CDF II detector at the Fermilab Tevatron, we find signals of 5600 fully reconstructed hadronic Bs decays, 3100 partially reconstructed hadronic Bs decays, and 61 500 partially reconstructed semileptonic Bs decays. We measure the probability as a function of proper decay time that the Bs decays with the same, or opposite, flavor as the flavor at production, and we find a signal for B0s−¯¯¯B0s oscillations. The probability that random fluctuations could produce a comparable signal is 8×10−8, which exceeds 5σ significance. We measure Δms=17.77±0.10(stat)±0.07(syst) ps−1 and extract |Vtd/Vts|=0.2060±0.0007(Δms)+0.0081−0.0060(Δmd+theor).Received 18 September 2006DOI:https://doi.org/10.1103/PhysRevLett.97.242003©2006 American Physical Society

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

We report the observation of single top-quark production using 3.2 fb−1 of pp¯ collision data with s=1.96 TeV collected by the Collider Detector at Fermilab. The significance of the observed data is 5.0 standard deviations, and the expected sensitivity for standard model production and decay is in excess of 5.9 standard deviations. Assuming mt=175 GeV/c2, we measure a cross section of 2.3−0.5+0.6(stat+syst) pb, extract the CKM matrix-element value |Vtb|=0.91±0.11(stat+syst)±0.07(theory), and set the limit |Vtb|>0.71 at the 95% C.L.Received 4 March 2009DOI:https://doi.org/10.1103/PhysRevLett.103.092002©2009 American Physical Society

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 combine searches by the CDF and D0 Collaborations for the associated production of a Higgs boson with a W or Z boson and subsequent decay of the Higgs boson to a bottom-antibottom quark pair. The data, originating from Fermilab Tevatron pp collisions at √s = 1.96 TeV, correspond to integrated luminosities of up to 9.7 fb(-1). The searches are conducted for a Higgs boson with mass in the range 100-150 GeV/c(2). We observe an excess of events in the data compared with the background predictions, which is most significant in the mass range between 120 and 135 GeV/c(2). The largest local significance is 3.3 standard deviations, corresponding to a global significance of 3.1 standard deviations. We interpret this as evidence for the presence of a new particle consistent with the standard model Higgs boson, which is produced in association with a weak vector boson and decays to a bottom-antibottom quark pair.

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

We have observed bottom-charm mesons B_c via the decay mode Bc -&gt; J/psi lepton neutrino in 1.8 TeV p-bar p collisions using the CDF detector at the Fermilab Tevatron. A fit of background and signal contributions to the J/psi + lepton mass distribution yielded 20.4 +6.2 -5.5 events from B_c mesons. A fit to the same distribution with background alone was rejected at the level of 4.8 standard deviations. We measured the B_c mass to be 6.40 +- 0.39 +- 0.13 GeVc^2 and the B_c lifetime to be tau(B_c) = 0.46 +0.18 -0.16 +- 0.03 ps. We measured the production cross section times branching ratio for B_c -&gt; J/psi lepton neutrino relative to that for B+ -&gt; J/psi K to be 0.132 +0.041 -0.037 (stat) +- 0.031 (syst) +0.032 -0.020 (lifetime).

The production and event topology of three-jet events produced in p¯p collisions at √s=1.8 TeV have been studied with the Collider Detector at Fermilab at the Tevatron Collider. The distributions of the three-jet angular variables (ψ∗ and cosθ∗) and of the variables describing the energy sharing between jets (x3 and x4) are found to agree well with tree-level QCD calculations. These distributions are predicted to have different shapes for different initial-state subprocesses (quark-antiquark, quark-gluon, and gluon-gluon). The data are consistent with the small expected contribution from quark-antiquark initial states, in agreement with theoretical expectations.Received 3 September 1991DOI:https://doi.org/10.1103/PhysRevD.45.1448©1992 American Physical Society

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 ${5.6}_{\ensuremath{-}1.1}^{+1.2}(\mathrm{stat}.{)}_{\ensuremath{-}0.6}^{+0.9}(\mathrm{syst}.)\text{ }\text{ }\mathrm{pb}$.

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.

Inclusive J/\ensuremath{\psi} and \ensuremath{\psi}(2S) production has been studied in p\ifmmode\bar\else\textasciimacron\fi{}p collisions at \ensuremath{\surd}s =1.8 TeV using 2.6\ifmmode\pm\else\textpm\fi{}0.2 ${\mathrm{pb}}^{\mathrm{\ensuremath{-}}1}$ of data taken with the Collider Detector at Fermilab. The products of production cross section times branching fraction were measured as functions of ${\mathit{P}}_{\mathit{T}}$ for J/\ensuremath{\psi}\ensuremath{\rightarrow}${\mathrm{\ensuremath{\mu}}}^{+}$${\mathrm{\ensuremath{\mu}}}^{\mathrm{\ensuremath{-}}}$ and \ensuremath{\psi}(2S)\ensuremath{\rightarrow}${\mathrm{\ensuremath{\mu}}}^{+}$${\mathrm{\ensuremath{\mu}}}^{\mathrm{\ensuremath{-}}}$. In the kinematic range ${\mathit{P}}_{\mathit{T}}$&gt;6 GeV/c and \ensuremath{\Vert}\ensuremath{\eta}\ensuremath{\Vert}\ensuremath{\le}0.5 we get \ensuremath{\sigma}(p\ifmmode\bar\else\textasciimacron\fi{}p\ensuremath{\rightarrow}J/\ensuremath{\psi} X)B(J/\ensuremath{\psi}\ensuremath{\rightarrow}${\mathrm{\ensuremath{\mu}}}^{+}$${\mathrm{\ensuremath{\mu}}}^{\mathrm{\ensuremath{-}}}$) =6.88\ifmmode\pm\else\textpm\fi{}0.23(stat${)}_{\mathrm{\ensuremath{-}}1.08}^{+0.93}$(syst) nb, and \ensuremath{\sigma}(p\ifmmode\bar\else\textasciimacron\fi{}p\ensuremath{\rightarrow}\ensuremath{\psi}(2S)X)B(\ensuremath{\psi}(2S)\ensuremath{\rightarrow}${\mathrm{\ensuremath{\mu}}}^{+}$${\mathrm{\ensuremath{\mu}}}^{\mathrm{\ensuremath{-}}}$) =0.232\ifmmode\pm\else\textpm\fi{}0.051(stat${)}_{\mathrm{\ensuremath{-}}0.032}^{+0.029}$(syst)nb. From these values we calculate the inclusive b-quark production cross section.

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.

This Letter describes the first determination of bounds on the CP-violation parameter 2βs using B0s decays in which the flavor of the bottom meson at production is identified. The result is based on approximately 2000 B0s→J/ψϕ decays reconstructed in a 1.35 fb−1 data sample collected with the CDF II detector using p¯p collisions produced at the Fermilab Tevatron. We report confidence regions in the two-dimensional space of 2βs and the decay-width difference ΔΓ. Assuming the standard model predictions of 2βs and ΔΓ, the probability of a deviation as large as the level of the observed data is 15%, corresponding to 1.5 Gaussian standard deviations.Received 14 December 2007DOI:https://doi.org/10.1103/PhysRevLett.100.161802©2008 American Physical Society

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 report the first measurements of inclusive W and Z boson cross sections times the corresponding leptonic branching ratios for p pbar collisions at sqrt{s} = 1.96 TeV based on the decays of the W and Z bosons into electrons and muons. The data were recorded with the CDF II detector at the Fermilab Tevatron and correspond to an integrated luminosity of 72.0 +/- 4.3 pb-1. We test e-mu lepton universality in W decays by measuring the ratio of the W->mu nu to W->e nu cross sections and determine a value of 0.991 +/- 0.004(stat.) +/- 0.011(syst.) for the ratio of W-l-nu couplings (g_mu/g_e). Since there is no sign of non-universality, we combine our cross section measurements in the different lepton decay modes and obtain sigma*BR(W->lnu) = 2.749 +/- 0.010(stat.) +/- 0.053(syst.) +/- 0.165(lum.) nb and sigma*BR(gamma*/Z->ll)=254.9 +/- 3.3(stat.) +/- 4.6(syst.) +/- 15.2(lum.) pb for dilepton pairs in the mass range between 66 GeV/c^2 and 116 GeV/c^2. We compute the ratio R of the W->lnu to Z->ll cross sections taking all correlations among channels into account and obtain R=10.84 +/- 0.15(stat.) +/- 0.14(syst.) including a correction for the virtual photon exchange component in our measured gamma*/Z->ll cross section. Based on the measured value of R, we extract values for the W leptonic branching ratio, BR(W->lnu) =0.1082 +/- 0.0022; the total width of the W boson, Gamma(W) =2092 +/- 42 MeV; and the ratio of W and Z boson total widths, Gamma(W)/Gamma(Z) = 0.838 +/- 0.017. In addition, we use our extracted value of Gamma(W) whose value depends on various electroweak parameters and certain CKM matrix elements to constrain the V_CS CKM matrix element, |V_CS| = 0.976 +/- 0.030.

The inclusive jet differential cross section has been measured for jet transverse energies, ET, from 15 to 440 GeV, in the pseudorapidity region 0.1≤|η|≤0.7. The results are based on 19.5pb−1 of data collected by the CDF Collaboration at the Fermilab Tevatron collider. The data are compared with QCD predictions for various sets of parton distribution functions. The cross section for jets with ET>200GeV is significantly higher than current predictions based on O(αs3) perturbative QCD calculations. Various possible explanations for the high- ET excess are discussed.Received 25 January 1996DOI:https://doi.org/10.1103/PhysRevLett.77.438©1996 American Physical Society

We report the observation of bottom-charmed mesons ${B}_{c}$ in 1.8 TeV $p\overline{p}$ collisions using the CDF detector at the Fermilab Tevatron. The ${B}_{c}$ mesons were found through their semileptonic decays, ${B}_{c}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}J/\ensuremath{\psi}{l}^{\ifmmode\pm\else\textpm\fi{}}X.$ A fit to the $J/\ensuremath{\psi}l$ mass distribution yielded ${20.4}_{\ensuremath{-}5.5}^{+6.2}$ events from ${B}_{c}$ mesons. A test of the null hypothesis, i.e., an attempt to fit the data with background alone, was rejected at the level of 4.8 standard deviations. By studying the quality of the fit as a function of the assumed ${B}_{c}$ mass, we determined ${M(B}_{c})=6.40\ifmmode\pm\else\textpm\fi{}0.39(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.13\mathrm{}(\mathrm{syst})\mathrm{}\mathrm{GeV}{/c}^{2}.$ From the distribution of trilepton intersection points in the plane transverse to the beam direction we measured the ${B}_{c}$ lifetime to be $\ensuremath{\tau}{(B}_{c}{)=0.46}_{\ensuremath{-}0.16}^{+0.18}(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.03\mathrm{}(\mathrm{syst})\mathrm{}\mathrm{ps}.$ We also measured the ratio of production cross section times branching fraction for ${B}_{c}^{+}\ensuremath{\rightarrow}J/\ensuremath{\psi}{l}^{+}\ensuremath{\nu}$ relative to that for ${B}^{+}\ensuremath{\rightarrow}J/\ensuremath{\psi}{K}^{+}$ to be $\frac{\ensuremath{\sigma}{(B}_{c})\ifmmode\times\else\texttimes\fi{}{B(B}_{c}\ensuremath{\rightarrow}J/\ensuremath{\psi}l\ensuremath{\nu})}{\ensuremath{\sigma}(B)\ifmmode\times\else\texttimes\fi{}B(\stackrel{\ensuremath{\rightarrow}}{B}J/\ensuremath{\psi}K)}{=0.132}_{\ensuremath{-}0.037}^{+0.041}{(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.031\mathrm{}(\mathrm{syst})}_{\mathrm{\ensuremath{-}}0.020}^{+0.032}(\mathrm{lifetime}).$

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 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 present measurements of the pseudorapidity (η) distribution of charged particles (dNchdη) produced within |η|≤3.5 in proton-antiproton collisions at √s of 630 and 1800 GeV. We measure dNchdη at η=0 to be 3.18±0.06(stat)±0.10(syst) at 630 GeV, and 3.95±0.03 (stat)±0.13(syst) at 1800 GeV. Many systematic errors in the ratio of dNchdη at the two energies cancel, and we measure 1.26±0.01±0.04 for the ratio of dNchdη at 1800 GeV to that at 630 GeV within |η|≤3. Comparing to lower-energy data, we observe an increase faster than ln(s) in dNchdη at η=0.Received 2 October 1989DOI:https://doi.org/10.1103/PhysRevD.41.2330©1990 American Physical Society

We have measured the polarizations of $\jpsi$ and $\psiprime$ mesons as functions of their transverse momentum $\pt$ when they are produced promptly in the rapidity range $|y|<0.6$ with $\pt \geq 5 \pgev$. The analysis is performed using a data sample with an integrated luminosity of about $800 \ipb$ collected by the CDF II detector. For both vector mesons, we find that the polarizations become increasingly longitudinal as $\pt$ increases from 5 to $30 \pgev$. These results are compared to the predictions of nonrelativistic quantum chromodynamics and other contemporary models. The effective polarizations of $\jpsi$ and $\psiprime$ mesons from $B$-hadron decays are also reported.

Measurements of inclusive transverse-momentum spectra for charged particles produced in proton-antiproton collisions at \ensuremath{\surd}2 of 630 and 1800 GeV are presented and compared with data taken at lower energies.

We report a measurement of the proton-antiproton total cross section, VT, at c.m.s.energies fi = 546 and .I800 GeV.Using the luminosity'independent method, we find Q=61.26&0.93 mb at ,/k546GeV and 80.03f2.24mb at fi = 1800 GeV.In this energy range, the ratio v,l/UT increases from 0.2lOkO.002to 0.246~0.004.

The growth and development of ``charged particle jets'' produced in proton-antiproton collisions at $1.8 \mathrm{TeV} $ are studied over a transverse momentum range from $0.5$ $\mathrm{GeV}/c$ to $50$ $\mathrm{GeV}/c.$ A variety of leading (highest transverse momentum) charged jet observables are compared with the QCD Monte Carlo models HERWIG, ISAJET, and PYTHIA. The models describe fairly well the multiplicity distribution of charged particles within the leading charged jet, the size of the leading charged jet, the radial distribution of charged particles and transverse momentum around the leading charged jet direction, and the momentum distribution of charged particles within the leading charged jet. The direction of the leading ``charged particle jet'' in each event is used to define three regions of $\ensuremath{\eta}\ensuremath{-}\ensuremath{\varphi}$ space. The ``toward'' region contains the leading ``charged particle jet,'' while the ``away'' region, on the average, contains the away-side jet. The ``transverse'' region is perpendicular to the plane of the hard $2$-to-$2$ scattering and is very sensitive to the ``underlying event'' component of the QCD Monte Carlo models. HERWIG, ISAJET, and PYTHIA with their default parameters do not describe correctly all the properties of the ``transverse'' region.

We present the first measurement of the Bs-Bsbar oscillation frequency Delta m_s. We use 1 fb^-1 of data from p-pbar collisions at sqrt{s}=1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. The sample contains signals of 3,600 fully reconstructed hadronic Bs decays and 37,000 partially reconstructed semileptonic Bs decays. We measure the probability as a function of proper decay time that the Bs decays with the same, or opposite, flavor as the flavor at production, and we find a signal consistent with Bs-Bsbar oscillations. The probability that random fluctuations could produce a comparable signal is 0.2%. Under the hypothesis that the signal is due to Bs-Bsbar oscillations, we measure Delta m_s = 17.31^{+0.33}_{-0.18} (stat.) +- 0.07 (syst.) ps^-1 and determine |Vtd/Vts| = 0.208^{+0.001}_{-0.002} (exp.) ^{+0.008}_{-0.006} (theo.).

A new measurement of the elastic scattering of 250-GeV/c negative pions by electrons provides form-factor results from $0.0368&lt;{q}^{2}&lt;0.0940$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$. These measurements determine the mean square pion radius to be $〈{{r}_{\ensuremath{\pi}}}^{2}〉=0.439\ifmmode\pm\else\textpm\fi{}0.030$ ${\mathrm{fm}}^{2}$ or ${〈{{r}_{\ensuremath{\pi}}}^{2}〉}^{\frac{1}{2}}=0.663\ifmmode\pm\else\textpm\fi{}0.023$ fm. Comparisons are made with previous elastic-scattering experiments as well as with results obtained from electroproduction experiments, ${e}^{+}{e}^{\ensuremath{-}}$ annihilation experiments, and phenomenological analyses.

We have performed a search for B0s→μ+μ− and B0→μ+μ− decays in p¯p collisions at √s=1.96 TeV using 2 fb−1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron Collider. The observed number of B0s and B0 candidates is consistent with background expectations. The resulting upper limits on the branching fractions are B(B0s→μ+μ−)<5.8×10−8 and B(B0→μ+μ−)<1.8×10−8 at 95% C.L.Received 12 December 2007DOI:https://doi.org/10.1103/PhysRevLett.100.101802©2008 American Physical Society

Kinematic properties of four-jet events produced in p¯p collisions at √s=1.8 TeV have been studied using data with an integrated luminosity of 325 nb−1 collected using the Collider Detector at Fermilab during the 1988-1989 Fermilab Collider run. The individual jet pT spectra and the angles between each jet pair are compared to the predictions of leading-order quantum chromodynamics for the double gluon bremsstrahlung process and good agreement is observed. In addition, a search for double parton scattering has been undertaken using variables sensitive to the topology of four-jet events. A small double parton content provides the best description of the data. We find NDPNDB=5.4+1.6−2.0%, where N represents the number of events attributed to each process. We measure σDP=63+32−28 nb for jets having pT>25 GeV/c in the pseudorapidity interval |η|<3.5.Received 11 January 1993DOI:https://doi.org/10.1103/PhysRevD.47.4857©1993 American Physical Society

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

A search for the top quark in p\ifmmode\bar\else\textasciimacron\fi{}p collisions at a center-of-mass energy of 1.8 TeV using the Collider Detector at Fermilab is described. A study of events selected by requiring an energetic electron, missing transverse energy, and two or more jets excludes at 95% confidence level the standard-model production and decay of tt\ifmmode\bar\else\textasciimacron\fi{} pairs if the top-quark mass is between 40 and 77 GeV/${c}^{2}$. The observed electron + multijet data are consistent with W-boson production.

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 combine searches by the CDF and D0 collaborations for a Higgs boson decaying to W+W-. The data correspond to an integrated total luminosity of 4.8 (CDF) and 5.4 (D0) fb-1 of p-pbar collisions at sqrt{s}=1.96 TeV at the Fermilab Tevatron collider. No excess is observed above background expectation, and resulting limits on Higgs boson production exclude a standard-model Higgs boson in the mass range 162-166 GeV at the 95% C.L.

We have measured the total cross-section difference for pp scattering in initial spin states parallel to the beam direction at beam momenta of 1.17, 1.47, 1.69, 1.97 and 2.49 GeV/c. This measurement was done in a standard transmission experiment. A striking energy dependence is observed with a maximum difference of −16.9 mb at Plab = 1.47 GeV/c.

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.

The top quark is the heaviest known elementary particle, with a mass about 40 times larger than the mass of its isospin partner, the bottom quark. It decays almost 100% of the time to a $W$ boson and a bottom quark. Using top-antitop pairs at the Tevatron proton-antiproton collider, the CDF and D0 Collaborations have measured the top quark's mass in different final states for integrated luminosities of up to $5.8\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. This paper reports on a combination of these measurements that results in a more precise value of the mass than any individual decay channel can provide. It describes the treatment of the systematic uncertainties and their correlations. The mass value determined is $173.18\ifmmode\pm\else\textpm\fi{}0.56\text{ }(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.75\text{ }(\mathrm{syst})\text{ }\text{ }\mathrm{GeV}$ or $173.18\ifmmode\pm\else\textpm\fi{}0.94\text{ }\text{ }\mathrm{GeV}$, which has a precision of $\ifmmode\pm\else\textpm\fi{}0.54%$, making this the most precise determination of the top-quark mass.

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

We have measured the difference between the pp total cross-sections for parallel and anti-parallel longitudinal spin states at beam momenta of 3 and 6 GeV/c. These results, combined with our previous measurements, at lower momenta, are useful in clarifying a striking structure appearing at around 1.5 GeV/c. We have also measured for the first time, the spin-spin correlation parameter CLL (t) in pp elastic scattering at 6 GeV/c. We observe evidence for an exchange with A1-like quantum-numbers.

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 combine searches by the CDF and D0 Collaborations for the standard model Higgs boson with mass in the range 90–200 GeV/c2 produced in the gluon-gluon fusion, WH, ZH, t¯tH, and vector boson fusion processes, and decaying in the H→b¯b, H→W+W−, H→ZZ, H→τ+τ−, and H→γγ modes. The data correspond to integrated luminosities of up to 10 fb−1 and were collected at the Fermilab Tevatron in p¯p collisions at √s=1.96 TeV. The searches are also interpreted in the context of fermiophobic and fourth generation models. We observe a significant excess of events in the mass range between 115 and 140 GeV/c2. The local significance corresponds to 3.0 standard deviations at mH=125 GeV/c2, consistent with the mass of the Higgs boson observed at the LHC, and we expect a local significance of 1.9 standard deviations. We separately combine searches for H→b¯b, H→W+W−, H→τ+τ−, and H→γγ. The observed signal strengths in all channels are consistent with the presence of a standard model Higgs boson with a mass of 125 GeV/c2.18 MoreReceived 26 March 2013DOI:https://doi.org/10.1103/PhysRevD.88.052014© 2013 American Physical Society

We have searched for heavy neutral gauge bosons (Z′) in dielectron and dimuon decay modes using 110pb−1 of ¯pp collisions at √s=1.8TeV collected with the Collider Detector at Fermilab. We present a limit on the production cross section times branching ratio of a Z′ boson decaying into dileptons as a function of Z′ mass. For mass MZ′>600GeV/c2, the upper limit is 40 fb at 95% confidence level. We set the lower mass limits of 690, 590, 620, 595, 565, 630, and 600GeV/c2 for Z′SM, Zψ, Zη, Zχ, ZI, ZLR, and ZALRM, respectively.Received 6 May 1997DOI:https://doi.org/10.1103/PhysRevLett.79.2192©1997 American Physical Society

We have analyzed events with jets and large missing transverse energy produced in p\ifmmode\bar\else\textasciimacron\fi{}p colisions at \ensuremath{\surd}s =1.8 TeV. The observed event rate is consistent with standard model predictions. In a version of the supersymmetry (SUSY) model with a light photino (${\mathit{m}}_{\ensuremath{\gamma}}$\ifmmode \tilde{}\else \~{}\fi{}15 GeV/${\mathit{c}}^{2}$) and no cascade decays, we exclude at the 90% confidence level the existence of squarks and gluinos with masses less than 126 and 141 GeV/${\mathit{c}}^{2}$, respectively. The mass limits are lower with other choices of the SUSY parameters. An example is presented.

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 present results from searches for the top quark pp\ifmmode\bar\else\textasciimacron\fi{} collisions at the Fermilab Tevatron Collider. The data sample was collected during 1988--89 with the Collider Detector at Fermilab and has an integrated luminosity of 4.1 ${\mathrm{pb}}^{\mathrm{\ensuremath{-}}1}$. Our previous search for e\ensuremath{\mu} final states for tt\ifmmode\bar\else\textasciimacron\fi{}\ensuremath{\rightarrow}e\ensuremath{\nu}b \ensuremath{\mu}\ensuremath{\nu}b\ifmmode\bar\else\textasciimacron\fi{} decays has been extended to include the ee and \ensuremath{\mu}\ensuremath{\mu} channels. In addition, we have searched in each event with a high-transverse-momentum lepton accompanied by hadron jets for a low-transverse-momentum muon as a tag of a bottom quark in tt\ifmmode\bar\else\textasciimacron\fi{}\ensuremath{\rightarrow}l\ensuremath{\nu}bqq\ifmmode\bar\else\textasciimacron\fi{}b\ifmmode\bar\else\textasciimacron\fi{} decays. A lower limit on the top-quark mass of 91 GeV/${\mathit{c}}^{2}$ is obtained at the 95% confidence level, assuming standard model decays.

This article presents a measurement of the top quark mass using the CDF II detector at Fermilab. Colliding beams of protons and anti-protons at Fermilab's Tevatron (sqrt{s}=1.96 TeV) produce top/anti-top pairs, which decay to W^+W^-bbbar; events are selected where one W decays to hadrons, and one W decays to either e or mu plus a neutrino. The data sample corresponds to an integrated luminosity of approximately 318 pb^-1. A total of 165 ttbar events are separated into four subsamples based on jet transverse energy thresholds and the number of b jets identified by reconstructing a displaced vertex. In each event, the reconstructed top quark invariant mass is determined by minimizing a chi-squared for the overconstrained kinematic system. At the same time, the mass of the hadronically decaying W boson is measured in the same event sample. The observed W boson mass provides an in situ improvement in the determination of the hadronic jet energy scale, JES. A simultaneous likelihood fit of the reconstructed top quark masses and the W boson invariant masses in the data sample to distributions from simulated signal and background events gives a top quark mass of 173.5 +3.7/-3.6 (stat.+JES) +/- 1.3 (other syst.) GeV/c^2, or 173.5 +3.9/-3.8 GeV/c^2.

We have determined mW=79.91±0.39 GeV/c2 from an analysis of W→eν and W→μν data from the Collider Detector at Fermilab in p¯p collisions at a c.m. energy of √s =1.8 TeV. This result, together with the world-average Z mass, determines the weak mixing angle to be sin2θW=0.232±0.008. Bounds on the top-quark mass are discussed.Received 13 August 1990DOI:https://doi.org/10.1103/PhysRevLett.65.2243©1990 American Physical Society

Antiproton-proton elastic scattering was measured at c.m.s. energies √s =546 and 1800 GeV in the range of four-momentum transfer squared 0.025<-t<0.29 GeV2. The data are well described by the exponential form ebt with a slope b=15.28±0.58 (16.98±0.25) GeV−2 at √s =546 (1800) GeV. The elastic scattering cross sections are, respectively, σel=12.87±0.30 and 19.70±0.85 mb.Received 5 August 1993DOI:https://doi.org/10.1103/PhysRevD.50.5518©1994 American Physical Society

We search for the flavor-changing neutral current decays of the top quark t→qγ and t→qZ (here q represents the c and u quarks) in ¯pp collisions at √s=1.8TeV. We use a dataset (∫Ldt∼110pb−1) collected during the 1992–1995 run of the Collider Detector at Fermilab. We set 95% confidence level limits on the branching fractions B(t→qγ)<3.2% and B(t→qZ)<33%, consistent with the standard model.Received 24 July 1997DOI:https://doi.org/10.1103/PhysRevLett.80.2525©1998 American Physical Society

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

The transverse momentum and total cross section of e^+e^- pairs in the Z-boson region of 66<M_{ee}<116 GeV$/c^2$ from $p\bar{p}$ collisions at $\sqrt{s}=1.8$ TeV are measured using 110 pb^{-1} of collisions taken by the Collider Detector at Fermilab during 1992-1995. The total cross section is measured to be $248 \pm 11$ pb. The differential transverse momentum cross section is compared with calculations that match quantum chromodynamics perturbation theory at high transverse momentum with the gluon resummation formalism at low transverse momentum.

This paper presents the first direct measurement of the $B$ meson differential cross section, $d\sigma/dp_T$, in $p\bar{p}$ collisions at $\sqrt{s}=1.8$ TeV using a sample of $19.3 \pm 0.7$ pb$^{-1}$ accumulated by the Collider Detector at Fermilab (CDF). The cross section is measured in the central rapidity region $|y| < 1$ for $p_T(B) > 6.0$ GeV/$c$ by fully reconstructing the $B$ meson decays $B^{+}\to J/\psi K^{+}$ and $B^{0}\to J/\psi K^{*0}(892)$, where $J/\psi \to \mu^+\mu^-$ and $K^{*0} \to K^+ \pi^-$. A comparison is made to the theoretical QCD prediction calculated at next-to-leading order.

The electromagnetic form factor of the negative kaon has been measured by direct scattering of 250-GeV/c kaons from the stationary electrons of a liquid-hydrogen target The deviation of the measured elastic scattering cross section from the point cross section may be characterized by a root-mean-square kaon radius of ${〈{{\mathcal{r}}_{{K}^{\ensuremath{-}}}}^{2}〉}^{\frac{1}{2}}=0.53\ifmmode\pm\else\textpm\fi{}0.05$ fm.

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 measure the dipion mass spectrum in X(3872)--> J/psipi(+) pi(-) decays using 360 pb(-1) of pp collisions at square root s= 1.96 TeV collected with the CDF II detector. The spectrum is fit with predictions for odd C-parity ((3)S(1), (1)P(1), and (3)D(J)) charmonia decaying to J/psipi(+) pi(-), as well as even C-parity states in which the pions are from rho(0) decay. The latter case also encompasses exotic interpretations, such as a D(0)D(*0) molecule. Only the (3)S(1) and J/psirho hypotheses are compatible with our data. Since (3)S(1) is untenable on other grounds, decay via J/psirho is favored, which implies C= +1 for the X(3872). Models for J/psi - rho different angular momenta L are considered. Flexibility in the models, especially the introduction of rho - omega interference, enables good descriptions of our data for both L = 0 and 1.

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 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.

An analysis of pp\ifmmode\bar\else\textasciimacron\fi{} collision events at \ensuremath{\surd}s =1.8 TeV with jets and large missing transverse energy finds no event with missing transverse energy &gt;40 GeV. This result yields a 90%-C.L. limit on the cross section for one-jet-event production of &lt;0.1 nb for events with the jet in the pseudorapidity range \ensuremath{\Vert}\ensuremath{\eta}\ensuremath{\Vert}&lt;1.0 and with jet ${E}_{T}$&gt;52 GeV. Limits on the masses of squarks and gluinos in a minimal supersymmetry model are also set. At the 90% C.L., ${m}_{q\ifmmode \tilde{}\else \~{}\fi{}}$&gt;74 GeV and ${m}_{g\ifmmode \tilde{}\else \~{}\fi{}}$&gt;73 GeV.

We measure the time dependence of the ratio of decay rates for the rare decay D{0}-->K{+}pi{-} to the Cabibbo-favored decay D{0}-->K{-}pi;{+}. A signal of 12.7x10;{3} D{0}-->K{+}pi{-} decays was obtained using the Collider Detector at Fermilab II detector at the Fermilab Tevatron with an integrated luminosity of 1.5 fb;{-1}. We measure the D0-D[over ]{0} mixing parameters (R_{D},y{'},x{'2}), and find that the data are inconsistent with the no-mixing hypothesis with a probability equivalent to 3.8 Gaussian standard deviations.

A prompt photon cross section measurement from the Collider Detector at Fermilab experiment is presented. Detector and trigger upgrades, as well as 6 times the integrated luminosity compared with our previous publication, have contributed to a much more precise measurement and extended PT range. As before, QCD calculations agree qualitatively with the measured cross section, but the data has a steeper slope than the calculations.Received 26 July 1994DOI:https://doi.org/10.1103/PhysRevLett.73.2662©1994 American Physical Society

We report the results of a search for a charged Higgs boson in the decays of top quarks produced in pp collisions at a center-of-mass energy of 1.96 TeV. We use a data sample corresponding to an integrated luminosity of 193 pb-1 collected by the upgraded Collider Detector at Fermilab. No evidence for charged Higgs production is found, allowing 95% C.L. upper limits to be placed on BR(t-->H+b) for different charged Higgs decay scenarios. In addition, we present in the minimal supersymmetric standard model (mH+/-, tanbeta) plane the first exclusion regions with radiative and Yukawa coupling corrections.

We report an observation of new bottom baryons produced in pp collisions at the Tevatron. Using 1.1 fb(-1) of data collected by the CDF II detector, we observe four Lambda b 0 pi+/- resonances in the fully reconstructed decay mode Lambda b 0-->Lambda c + pi-, where Lambda c+-->pK* pi+. We interpret these states as the Sigma b(*)+/- baryons and measure the following masses: m Sigma b+=5807.8 -2.2 +2.0(stat.)+/-1.7(syst.) MeV/c2, m Sigma b- =5815.2+/-1.0(stat.)+/-1.7(syst.) MeV/c2, and m(Sigma b*)-m(Sigma b)=21.2-1.9 +2.0(stat.)-0.3+0.4(syst.) MeV/c2.

The Bc+/- meson is observed through the decay Bc+/--->J/psipi+/-, in data corresponding to an integrated luminosity of 2.4 fb(-1) recorded by the Collider Detector at Fermilab II detector at the Fermilab Tevatron. A signal of 108+/-15 candidates is observed, with a significance that exceeds 8sigma. The mass of the Bc+/- meson is measured to be 6275.6+/-2.9(stat)+/-2.5(syst) MeV/c2.

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 ${m}_{t}=175\text{ }\text{ }\mathrm{GeV}/{c}^{2}$.

The existence of a diproton resonance is indicated by the energy dependence of Legendre expansion coefficients of P dσdΩ for pp elastic scattering and the structure appearing in the data of ΔσL = σTot(⇄) − σTot(→). The properties of such a resonance are described.

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 report the observation and measurement of the mass of the bottom, strange baryon $\Xi^-_b$ through the decay chain $\Xi^-_b \to J/\psi \Xi^-$, where $J/\psi \to \mu^+ \mu^-$, $\Xi^- \to \Lambda \pi^-$, and $\Lambda \to p \pi^-$. Evidence for observation is based on a signal whose probability of arising from the estimated background is 6.6 x 10^{-15}, or 7.7 Gaussian standard deviations. The $\Xi^-_b$ mass is measured to be $5792.9\pm 2.5$ (stat.) $\pm 1.7$ (syst.) MeV/$c^2$.

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.

Inclusive jet cross sections in Z/γ∗ events, with Z/γ∗ decaying into an electron-positron pair, are measured as a function of jet transverse momentum and jet multiplicity in p¯p collisions at √s=1.96 TeV with the upgraded Collider Detector at Fermilab in run II, based on an integrated luminosity of 1.7 fb−1. The measurements cover the rapidity region |yjet|<2.1 and the transverse momentum range pjetT>30 GeV/c. Next-to-leading order perturbative QCD predictions are in good agreement with the measured cross sections.Received 23 November 2007DOI:https://doi.org/10.1103/PhysRevLett.100.102001©2008 American Physical Society

We summarize and combine direct measurements of the mass of the W boson in √s=1.96 TeV proton-antiproton collision data collected by CDF and D0 experiments at the Fermilab Tevatron Collider. Earlier measurements from CDF and D0 are combined with the two latest, more precise measurements: a CDF measurement in the electron and muon channels using data corresponding to 2.2 fb−1 of integrated luminosity, and a D0 measurement in the electron channel using data corresponding to 4.3 fb−1 of integrated luminosity. The resulting Tevatron average for the mass of the W boson is MW=80387±16 MeV. Including measurements obtained in electron-positron collisions at LEP yields the most precise value of MW=80385±15 MeV.Received 29 July 2013DOI:https://doi.org/10.1103/PhysRevD.88.052018© 2013 American Physical Society

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 present a measurement of the cross section for W-boson production in association with jets in p¯p collisions at √s=1.96 TeV. The analysis uses a data sample corresponding to an integrated luminosity of 320 pb−1 collected with the CDF II detector. W bosons are identified in their electron decay channel and jets are reconstructed using a cone algorithm. For each W+≥n−jet sample (n=1−4) we measure the differential cross section dσ(p¯p→W+≥n−jet)/dEnth−jetT×B(W→eν) with respect to the transverse energy ET of the nth-highest ET jet above 20 GeV, and the total cross section σ(p¯p→W+≥n−jet;Enth−jetT>25 GeV)×B(W→eν), for a restricted W→eν decay phase space. The cross sections, corrected for all detector effects, can be directly compared to particle level W+jet(s) predictions. We present here comparisons to leading order and next-to-leading order predictions.Received 26 November 2007DOI:https://doi.org/10.1103/PhysRevD.77.011108©2008 American Physical Society

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 combine six measurements of the inclusive top-quark pair (ttbar) production cross section (sigma_ttbar) from data collected with the CDF and D0 detectors at the Fermilab Tevatron with proton anti-proton collisions at sqrt{s} = 1.96 TeV. The data correspond to integrated luminosities of up to 8.8 fb^{-1}. We obtain a value of sigma_ttbar = 7.60 \pm 0.41 pb for a top-quark mass of m_t=172.5 GeV. The contributions to the uncertainty are 0.20 pb from statistical sources, 0.29 pb from systematic sources, and 0.21 pb from the uncertainty on the integrated luminosity. The result is in good agreement with the standard model expectation of 7.35^{+0.28}_{-0.33} pb at NNLO+NNLL in pertubative QCD.

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 report the first observation of single-top-quark production in the s channel through the combination of the CDF and D0 measurements of the cross section in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. The data correspond to total integrated luminosities of up to 9.7 fb−1 per experiment. The measured cross section is σs=1.29+0.26−0.24 pb. The probability of observing a statistical fluctuation of the background to a cross section of the observed size or larger is 1.8×10−10, corresponding to a significance of 6.3 standard deviations for the presence of an s-channel contribution to the production of single-top quarks.Received 21 February 2014DOI:https://doi.org/10.1103/PhysRevLett.112.231803© 2014 American Physical Society

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

We present the final combination of CDF and D0 measurements of cross sections for single-top-quark production in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. The data correspond to total integrated luminosities of up to 9.7 fb^{-1} per experiment. The t-channel cross section is measured to be σ_{t}=2.25_{-0.31}^{+0.29} pb. We also present the combinations of the two-dimensional measurements of the s- vs t-channel cross section. In addition, we give the combination of the s+t channel cross section measurement resulting in σ_{s+t}=3.30_{-0.40}^{+0.52} pb, without assuming the standard model value for the ratio σ_{s}/σ_{t}. The resulting value of the magnitude of the top-to-bottom quark coupling is |V_{tb}|=1.02_{-0.05}^{+0.06}, corresponding to |V_{tb}|>0.92 at the 95% C.L.

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

We report results from a study of events with a leading antiproton of beam momentum fraction 0.905<x(F)<0.965 and 4-momentum transfer squared |t|<3 GeV2 produced in &pmacr;p collisions at sqrt[s] = 1800 GeV at the Fermilab Tevatron collider. Approximately 2% of the events contain two jets of transverse energy E(jet)(T)>7 GeV. Using the dijet events, we evaluate the diffractive structure function of the antiproton and compare it with expectations based on results obtained in diffractive deep inelastic scattering experiments at the DESY ep collider HERA.

A strong signal for double parton scattering (DP) is observed in a $16\mathrm{pb}{}^{\ensuremath{-}1}$ sample of $\overline{p}p\ensuremath{\rightarrow}\ensuremath{\gamma}+3\mathrm{jets}+X$ data from the CDF experiment at the Fermilab Tevatron. The process-independent DP parameter, ${\ensuremath{\sigma}}_{\mathrm{eff}}$, is obtained without reference to theoretical calculations by comparing observed DP events to events with hard scatterings at separate $\overline{p}p$ collisions. The result, ${\ensuremath{\sigma}}_{\mathrm{eff}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}(14.5\ifmmode\pm\else\textpm\fi{}{1.7}_{\ensuremath{-}2.3}^{+1.7})\mathrm{mb}$, represents a significant improvement over previous measurements. For the first time, the Feynman $x$ dependence of the ${\ensuremath{\sigma}}_{\mathrm{eff}}$ parameter is investigated, and no dependence is seen.

This paper reports an updated measurement of the Standard Model CP violation parameter $\sin2\beta$ using the CDF Detector at Fermilab. The entire Run I data sample of 110 pb$^{-1}$ of proton antiproton collisions at $\sqrt{s}=1.8 TeV$ is used to identify a signal sample of $\sim 400$ $B \to J/\psi K^0_S$ events, where $J/\psi \to \mu^+\mu^-$ and $K_S^0 \to \pi^+\pi^-$. The flavor of the neutral B meson is identified at the time of production by combining information from three tagging algorithms: a same-side tag, a jet-charge tag, and a soft-lepton tag. A maximum likelihood fitting method is used to determine $\sin2\beta = 0.79 {+0.41\atop-0.44}$(stat+syst). This value of $\sin 2 \beta$ is consistent with the Standard Model prediction, based upon existing measurements, of a large positive CP violating asymmetry in this decay mode.

We report a measurement of the diffraction dissociation differential cross section ${\mathit{d}}^{2}$${\mathrm{\ensuremath{\sigma}}}_{\mathrm{SD}}$/${\mathit{dM}}^{2}$dt for p\ifmmode\bar\else\textasciimacron\fi{}p\ensuremath{\rightarrow}p\ifmmode\bar\else\textasciimacron\fi{}X at \ensuremath{\surd}s =546 and 1800 GeV, ${\mathit{M}}^{2}$/s0.2 and 0\ensuremath{\le}-t\ensuremath{\le}0.4 ${\mathrm{GeV}}^{2}$. Our results are compared to theoretical predictions and to extrapolations from experimental results at lower energies.

A search for tt\ifmmode\bar\else\textasciimacron\fi{}\ensuremath{\rightarrow}e\ensuremath{\mu}+X in pp\ifmmode\bar\else\textasciimacron\fi{} collisions at s\ensuremath{\surd}\ifmmode\bar\else\textasciimacron\fi{} TeV is described. The production and decay of top-quark--antiquark pairs is considered in the context of the standard model. The analysis is based on data with an integrated luminosity of 4.4 ${\mathrm{pb}}^{\mathrm{\ensuremath{-}}1}$ recorded with the Collider Detector at Fermilab. An upper limit on the tt\ifmmode\bar\else\textasciimacron\fi{} cross section is obtained, and the top quark in the mass range 28--72 GeV/${c}^{2}$ is excluded at the 95% C.L. The same limits apply to a possible fourth-generation, charge -(1/3, b' quark, decaying via the charged current.

This Letter describes a direct search for charged Higgs boson production in $p\overline{p}$ collisions at $\sqrt{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.8\mathrm{TeV}$ recorded by the Collider Detector at Fermilab. Two-Higgs-double extensions to the standard model predict the existence of charged Higgs bosons $({H}^{\ifmmode\pm\else\textpm\fi{}})$. In such models, the branching fraction for top quarks $B(t\ensuremath{\rightarrow}{H}^{+}b\ensuremath{\rightarrow}{\ensuremath{\tau}}^{+}\ensuremath{\nu}b)$ can be large. This search uses the hadronic decays of the tau lepton in this channel to significantly extend previous limits on ${H}^{\ifmmode\pm\else\textpm\fi{}}$ production.

This paper presents a measurement of the mass of the W boson using data collected with the CDF detector during the 1992–1993 collider run at the Fermilab Tevatron. A fit to the transverse mass spectrum of a sample of 3268 W→μν events recorded in an integrated luminosity of 19.7 pb−1 gives MμW=80.310±0.205 (stat)±0.130 (syst) GeV/c2. A fit to the transverse mass spectrum of a sample of 5718 W→eν events recorded in 18.2 pb−1 gives MeW=80.490±0.145 (stat)±0.175 (syst) GeV/c2. Combining the muon and electron results, accounting for correlated uncertainties, yields MW=80.410±0.180 GeV/c2.Received 7 March 1995DOI:https://doi.org/10.1103/PhysRevD.52.4784©1995 American Physical Society