Search for the Exotic Meson X(5568) with the Collider Detector at Fermilab

A search for the exotic meson X(5568) decaying into the B[subscript s][superscript 0]π[superscript ±] final state is performed using data corresponding to 9.6  fb[superscript -1] from pp[over ¯] collisions at sqrt[s]=1960  GeV recorded by the Collider Detector at Fermilab. No evidence for this state is found and an upper limit of 6.7% at the 95% confidence level is set on the fraction of B[subscript s][superscript 0] produced through the X(5568)→B[subscript s][superscript 0]π[superscript ±} process

Search for standard-model Z and Higgs bosons decaying into a bottom-antibottom quark pair in proton-antiproton collisions at 1.96 TeV

The Collider Detector at Fermilab collected a unique sample of jets originating from bottom-quark fragmentation (b-jets) by selecting online proton-antiproton (pp̄) collisions with a vertex displaced from the pp̄ interaction point, consistent with the decay of a bottom-quark hadron. This data set, collected at a center-of-mass energy of 1.96 TeV, and corresponding to an integrated luminosity of 5.4 fb-1, is used to measure the Z-boson production cross section times branching ratio into bb̄. The number of Z→bb̄ events is determined by fitting the dijet-mass distribution, while constraining the dominant b-jet background, originating from QCD multijet events, with data. The result, σ(pp̄→Z)×B(Z→bb̄)=1.11±0.08(stat)±0.14(syst) nb, is the most precise measurement of this process, and is consistent with the standard-model prediction. The data set is also used to search for Higgs-boson production. No significant signal is expected in our data and the first upper limit on the cross section for the inclusive pp̄→H→bb̄ process at s=1.96 TeV is set, corresponding to 33 times the expected standard-model cross section, or σ=40.6 pb, at the 95% confidence level

Search for standard-model Z and Higgs bosons decaying into a bottom-antibottom quark pair in proton-antiproton collisions at 1.96 TeV

The Collider Detector at Fermilab collected a unique sample of jets originating from bottom-quark fragmentation (b-jets) by selecting online proton-antiproton (p[¯ over p]) collisions with a vertex displaced from the p[¯ over p] interaction point, consistent with the decay of a bottom-quark hadron. This data set, collected at a center-of-mass energy of 1.96 TeV, and corresponding to an integrated luminosity of 5.4  fb[superscript -1], is used to measure the Z-boson production cross section times branching ratio into b[¯ over b]. The number of Z→b[¯ over b] events is determined by fitting the dijet-mass distribution, while constraining the dominant b-jet background, originating from QCD multijet events, with data. The result, σ(p[¯ over p]→Z)×B(Z→b[¯ over b])=1.11 ± 0.08(stat) ± 0.14(syst)  nb, is the most precise measurement of this process, and is consistent with the standard-model prediction. The data set is also used to search for Higgs-boson production. No significant signal is expected in our data and the first upper limit on the cross section for the inclusive p[¯ over p]→H→b[¯ over b] process at √s=1.96  TeV is set, corresponding to 33 times the expected standard-model cross section, or σ=40.6  pb, at the 95% confidence level.National Science Foundation (U.S.)United States. Department of EnergyAlfred P. Sloan Foundatio

Search for the Exotic Meson X(5568) with the Collider Detector at Fermilab

A search for the exotic meson X(5568) decaying into the Bs0π± final state is performed using data corresponding to 9.6 fb-1 from pp̄ collisions at s=1960 GeV recorded by the Collider Detector at Fermilab. No evidence for this state is found and an upper limit of 6.7% at the 95% confidence level is set on the fraction of Bs0 produced through the X(5568)→Bs0π± process

Tevatron Run II combination of the effective leptonic electroweak mixing angle

Drell-Yan lepton pairs produced in the process pp→â.,"+â.,"-+X through an intermediate γ∗/Z boson have an asymmetry in their angular distribution related to the spontaneous symmetry breaking of the electroweak force and the associated mixing of its neutral gauge bosons. The CDF and D0 experiments have measured the effective-leptonic electroweak mixing parameter sin2θefflept using electron and muon pairs selected from the full Tevatron proton-antiproton data sets collected in 2001-2011, corresponding to 9-10 fb-1 of integrated luminosity. The combination of these measurements yields the most precise result from hadron colliders, sin2θefflept=0.23148±0.00033. This result is consistent with, and approaches in precision, the best measurements from electron-positron colliders. The standard model inference of the on-shell electroweak mixing parameter sin2θW, or equivalently the W-boson mass MW, using the zfitter software package yields sin2θW=0.22324±0.00033 or equivalently, MW=80.367±0.017 GeV/c2

Study of orbitally excited B mesons and evidence for a new B pi resonance

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 pi(+) and B+pi(-) 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) B-s2*(0) state to either B*K-+(-) and B+K-. Furthermore, we measure the production rates of the orbitally excited B-0,B-+ states relative to the B-0,B-+ ground state. The masses of the new B(5970) resonances are 5978 +/- 5(stat) +/- 12(syst)MeV/c(2) for the neutral state and 5961 +/- 5(stat) +/- 12(syst) MeV/c(2) for the charged state, assuming that the resonance decays into B pi final states. The properties of the orbitally excited and the new B(5970)(0,+) states are compatible with isospin symmetry

Measurement of the ZZ production cross section using the full CDF II data set

We present a measurement of the ZZ-boson pair-production cross section in 1.96 TeV center-of-mass energy p (p) over bar collisions. We reconstruct final states incorporating four charged leptons or two charged leptons and two neutrinos from the full data set collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.7 fb(-1) of integrated luminosity. Combining the results obtained from each final state, we measure a cross section of 1.04(-0.25)(+0.32) pb, in good agreement with the standard model prediction at next-to-leading order in the strong-interaction coupling

Indirect measurement of sin(2)theta(W) (or M-W) using mu(+)mu(-) pairs from gamma*/Z bosons produced in p(p)over-bar collisions at a center-of-momentum energy of 1.96 TeV

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

Study of top quark production and decays involving a tau lepton at CDF and limits on a charged Higgs boson contribution

We present an analysis of top-antitop quark production and decay into a tau lepton, tau neutrino, and bottom quark using data from 9 fb(-1) of integrated luminosity at the Collider Detector at Fermilab. Dilepton events, where one lepton is an energetic electron or muon and the other a hadronically decaying tau lepton, originating from proton-antiproton collisions at root s = 1.96 TeV, are used. A top-antitop quark production cross section of 8.1 +/- 2.1 pb is measured, assuming standard-model top quark decays. By separately identifying for the first time the single-tau and the ditau components, we measure the branching fraction o

Invariant-mass distribution of jet pairs produced in association with a W boson in p(p)over-bar collisions at root s=1.96 TeV using the full CDF Run II data set

We report on a study of the dijet invariant-mass distribution in events with one identified lepton, a significant imbalance in the total event transverse momentum, and two jets. This distribution is sensitive to the possible production of a new particle in association with a W boson, where the boson decays leptonically. We use the full data set of proton-antiproton collisions at 1.96 TeV center-of-mass energy collected by the Collider Detector at the Fermilab Tevatron, corresponding to an integrated luminosity of 8.9 fb(-1). The data are found to be consistent with standard model expectations, and a 95% confidence level upper limit is set on the production cross section of a W boson in association with a new particle decaying into two jets