28 research outputs found
Search for the standard model Higgs boson decaying to a bb pair in events with one charged lepton and large missing transverse energy using the full CDF data set
We present a search for the standard model Higgs boson produced in
association with a W boson in sqrt(s) = 1.96 TeV p-pbar collision data
collected with the CDF II detector at the Tevatron corresponding to an
integrated luminosity of 9.45 fb-1. In events consistent with the decay of the
Higgs boson to a bottom-quark pair and the W boson to an electron or muon and a
neutrino, we set 95% credibility level upper limits on the WH production cross
section times the H->bb branching ratio as a function of Higgs boson mass. At a
Higgs boson mass of 125 GeV/c2 we observe (expect) a limit of 4.9 (2.8) times
the standard model value.Comment: Submitted to Phys. Rev. Lett (v2 contains clarifications suggested by
PRL
Search for the standard model Higgs boson decaying to a pair in events with no charged leptons and large missing transverse energy using the full CDF data set
We report on a search for the standard model Higgs boson produced in
association with a vector boson in the full data set of proton-antiproton
collisions at TeV recorded by the CDF II detector at the
Tevatron, corresponding to an integrated luminosity of 9.45 fb. We
consider events having no identified charged lepton, a transverse energy
imbalance, and two or three jets, of which at least one is consistent with
originating from the decay of a quark. We place 95% credibility level upper
limits on the production cross section times standard model branching fraction
for several mass hypotheses between 90 and . For a Higgs
boson mass of , the observed (expected) limit is 6.7
(3.6) times the standard model prediction.Comment: Accepted by Phys. Rev. Let
Search for the standard model Higgs boson decaying to a bb pair in events with two oppositely-charged leptons using the full CDF data set
We present a search for the standard model Higgs boson produced in
association with a Z boson in data collected with the CDF II detector at the
Tevatron, corresponding to an integrated luminosity of 9.45/fb. In events
consistent with the decay of the Higgs boson to a bottom-quark pair and the Z
boson to electron or muon pairs, we set 95% credibility level upper limits on
the ZH production cross section times the H -> bb branching ratio as a function
of Higgs boson mass. At a Higgs boson mass of 125 GeV/c^2 we observe (expect) a
limit of 7.1 (3.9) times the standard model value.Comment: To be submitted to Phys. Rev. Let
Search for Neutral Higgs Bosons in Events with Multiple Bottom Quarks at the Tevatron
The combination of searches performed by the CDF and D0 collaborations at the
Fermilab Tevatron Collider for neutral Higgs bosons produced in association
with b quarks is reported. The data, corresponding to 2.6 fb-1 of integrated
luminosity at CDF and 5.2 fb-1 at D0, have been collected in final states
containing three or more b jets. Upper limits are set on the cross section
multiplied by the branching ratio varying between 44 pb and 0.7 pb in the Higgs
boson mass range 90 to 300 GeV, assuming production of a narrow scalar boson.
Significant enhancements to the production of Higgs bosons can be found in
theories beyond the standard model, for example in supersymmetry. The results
are interpreted as upper limits in the parameter space of the minimal
supersymmetric standard model in a benchmark scenario favoring this decay mode.Comment: 10 pages, 2 figure
Measurement of the difference of CP-violating asymmetries in D0 -> K+K- and D0 ->pi+pi- decays at CDF
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.Comment: Phys. Rev. Lett. 109, 111801 (2012
Tevatron Combination of Single-Top-Quark Cross Sections and Determination of the Magnitude of the Cabibbo-Kobayashi-Maskawa Matrix Element Vtb
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 st=2.25+0.29-0.31??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 ss+t=3.30+0.52-0.40??pb, without assuming the standard model value for the ratio ss/st. The resulting value of the magnitude of the top-to-bottom quark coupling is |Vtb|=1.02+0.06-0.05, corresponding to |Vtb|>0.92 at the 95% C.L
Combination of the top-quark mass measurements from the Tevatron collider
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 boson and a bottom quark. Using top-antitop
pairs at the Tevatron proton-antiproton collider, the CDF and {\dzero}
collaborations have measured the top quark's mass in different final states for
integrated luminosities of up to 5.8 fb. 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 GeV or GeV, which has a precision of , making this the most precise determination of the top quark mass.Comment: 30 pages and 6 figures, published in Phys. Rev.
Combined Tevatron upper limit on gg->H->W+W- and constraints on the Higgs boson mass in fourth-generation fermion models
Report number: FERMILAB-PUB-10-125-EWe combine results from searches by the CDF and D0 collaborations for a standard model Higgs boson (H) in the process gg->H->W+W- in p=pbar collisions at the Fermilab Tevatron Collider at sqrt{s}=1.96 TeV. With 4.8 fb-1 of integrated luminosity analyzed at CDF and 5.4 fb-1 at D0, the 95% Confidence Level upper limit on \sigma(gg->H) x B(H->W+W-) is 1.75 pb at m_H=120 GeV, 0.38 pb at m_H=165 GeV, and 0.83 pb at m_H=200 GeV. Assuming the presence of a fourth sequential generation of fermions with large masses, we exclude at the 95% Confidence Level a standard-model-like Higgs boson with a mass between 131 and 204 GeV.We combine results from searches by the CDF and D0 collaborations for a standard model Higgs boson (H) in the process gg→H→W+W- in pp̅ collisions at the Fermilab Tevatron Collider at √s=1.96 TeV. With 4.8 fb-1 of integrated luminosity analyzed at CDF and 5.4 fb-1 at D0, the 95% confidence level upper limit on σ(gg→H)×B(H→W+W-) is 1.75 pb at mH=120 GeV, 0.38 pb at mH=165 GeV, and 0.83 pb at mH=200 GeV. Assuming the presence of a fourth sequential generation of fermions with large masses, we exclude at the 95% confidence level a standard-model-like Higgs boson with a mass between 131 and 204 GeV.Peer reviewe
Higgs Boson Studies at the Tevatron
We combine searches by the CDF and D0 Collaborations for the standard model Higgs boson with mass in the range 90--200 GeV produced in the gluon-gluon fusion, , , , and vector boson fusion processes, and decaying in the , , , , and modes. The data correspond to integrated luminosities of up to 10 fb and were collected at the Fermilab Tevatron in collisions at 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/. The local significance corresponds to 3.0 standard deviations at GeV/, 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 , , , and . The observed signal strengths in all channels are consistent with the presence of a standard model Higgs boson with a mass of 125 GeV/