Search for standard-model Z and Higgs bosons decaying into a bottom-antibottom quark pair in proton-antiproton collisions at 1.96 TeV SEARCH for STANDARD-MODEL Z and HIGGS ... T. AALTONEN et al

The Collider Detector at Fermilab collected a unique sample of jets originating from bottom-quark fragmentation ($b$-jets) by selecting online proton-antiproton ($p\bar{p}$) collisions with a vertex displaced from the $p\bar{p}$ interaction point, consistent with the decay of a bottom-quark hadron. This data set, collected at a center-of-mass energy of $\sqrt{s}=$1.96 TeV, and corresponding to an integrated luminosity of $5.4~\rm{fb}^{-1}$, is used to measure the $Z$-boson production cross section times branching ratio into $b\bar{b}$. The number of $Z\rightarrow b\bar{b}$ 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, $\sigma(p\bar{p} \rightarrow Z) \times \mathcal{B}(Z \rightarrow b\bar{b})= 1.11\pm 0.08(\text{stat}) \pm 0.14(\text{syst})~\text{nb}$, 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 $p\bar p \rightarrow H\rightarrow b\bar b$ process at $\sqrt{s}=$1.96 TeV is set, corresponding to 33 times the expected standard-model cross section, or $\sigma = 40.6$ pb, at the 95\% confidence level

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

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

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 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

Search for B-s(0) -> mu(+) mu(-) and B-0 -> mu(+) mu(-) decays with the full CDF Run II data set (vol 87, 072003, 2013)

Erratum: Search for Bs0 →μ+μ- and B0 →μ+μ- decays with the full CDF Run II data set (Physical Review D (2013) 87 (072003

First Search for Exotic Z Boson Decays into Photons and Neutral Pions in Hadron Collisions

A search for forbidden and exotic Z boson decays in the diphoton mass spectrum is presented for the first time in hadron collisions, based on data corresponding to 10.0 fb(-1) of integrated luminosity from proton-antiproton collisions at root s = 1.96 TeV collected by the CDF experiment. No evidence of signal is observed, and 95% credibility level Bayesian upper limits are set on the branching ratios of decays of the Z boson to a photon and neutral pion (which is detected as a photon), a pair of photons, and a pair of neutral pions. The observed branching ratio limits are 2.01 x 10(-5) for Z -> pi(0)gamma, 1.46 x 10(-5) for Z -> gamma gamma, and 1.52 x 10(-5) for Z -> pi(0)pi(0). The Z -> pi(0)gamma and Z -> gamma gamma limits improve the most stringent results from other experiments by factors of 2.6 and 3.6, respectively. The Z -> pi(0)pi(0) branching ratio limit is the first experimental result on this decay

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

Measurements of Direct CP-Violating Asymmetries in Charmless Decays of Bottom Baryons

We report final 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 the complete root s = 1.96 TeV proton-antiproton collisions data set, corresponding to 9.3 fb(-1) of integrated luminosity, we measure A(A(b)(0) -> p pi(-)) = +0.06 +/- 0.07(stat) +/- 0.03(syst) and A(A(b)(0) -> pK(-)) = -0.10 +/- 0.08(stat) +/- 0.04(syst), compatible with no asymmetry. In addition we measure the CP-violating asymmetries in B-s(0) -> K-pi(-) and B-0 -> K+pi(-) decays to be A(B-s(0) -> K-pi(-)) = +0.22 +/- 0.07(stat) +/- 0.02(syst) and A(B-0 -> K+pi(-)) = -0.083 +/- 0.013(stat) +/- 0.004(syst), respectively, which are significantly different from zero and consistent with current world averages

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