Showing papers by "M. J. Shochet published in 2008"
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TL;DR: In this article, a detailed study of the expected performance of the ATLAS detector is presented, together with the reconstruction of tracks, leptons, photons, missing energy and jets, along with the performance of b-tagging and the trigger.
Abstract: A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN.
1,160 citations
TL;DR: In this article, the authors presented a measurement of the inclusive jet cross section in p-pbar collisions at sqrt{s}=1.96 TeV based on data collected by the CDF II detector with an integrated luminosity of 1.13 fb^-1.1
Abstract: We present a measurement of the inclusive jet cross section in p-pbar collisions at sqrt{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 k_T 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.
188 citations
TL;DR: In this paper, the first observation and cross section measurement of exclusive dijet production in {bar p}p interactions was presented, where the exclusive signal was extracted from fits to data distributions based on Monte Carlo simulations of expected dijet signal and background shapes, and the simulated background distribution shapes were checked in a study of a largely independent data sample of 200 pb{sup -1} of b-tagged jet events.
Abstract: The authors present the first observation and cross section measurement of exclusive dijet production in {bar p}p interactions, {bar p}p {yields} {bar p} + dijet + p. Using a data sample of 310 pb{sup -1} collected by the Run II Collider Detector at Fermilab at {radical}s = 1.96 TeV, exclusive cross sections for events with two jets of transverse energy E{sub T}{sup jet} {ge} 10 GeV have been measured as a function of minimum E{sub T}{sup jet}. The exclusive signal is extracted from fits to data distributions based on Monte Carlo simulations of expected dijet signal and background shapes. The simulated background distribution shapes are checked in a study of a largely independent data sample of 200 pb{sup -1} of b-tagged jet events, where exclusive dijet production is expected to be suppressed by the J{sub z} = 0 total angular momentum selection rule. Results obtained are compared with theoretical expectations, and implications for exclusive Higgs boson production at the pp Large Hadron Collider at {radical}s = 14 TeV are discussed.
108 citations
TL;DR: In this paper, the results of searches for large extra dimensions in samples of events with large missing transverse energy E_{T} and either a photon or a jet produced in pp[over ] collisions at sqrt[s]=1.96 TeV were presented.
Abstract: We present the results of searches for large extra dimensions in samples of events with large missing transverse energy E_{T} and either a photon or a jet produced in pp[over ] collisions at sqrt[s]=1.96 TeV collected with the Collider Detector at Fermilab II. For gamma+E_{T} and jet+E_{T} candidate samples corresponding to 2.0 and 1.1 fb;{-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.
97 citations
TL;DR: In this paper, the authors measured the time dependence of the ratio of decay rates for the rare decay D0->K+pi- to the Cabibbo-favored decay D 0->K-pi+.
Abstract: We measure the time dependence of the ratio of decay rates for the rare decay D0->K+pi- to the Cabibbo-favored decay D0->K-pi+. We use a signal of 12.7 x10^3 D0->K+pi decays with proper decay times between 0.75 and 10 mean D0 lifetimes. The data sample was recorded with the CDF II detector at the Fermilab Tevatron and corresponds to an integrated luminosity of 1.5 fb-1 of p-pbar collisions at sqrt(s) = 1.96 TeV. We search for D0-D0bar mixing and measure the mixing parameters to be Rd = (3.04 +/- 0.55) x10^{-3}, y' = (8.5 +/- 7.6) x10^{-3}, and x'^2 = (-0.12 +/- 0.35) x10^{-3}. We report Bayesian probability contours in the x'^2-y' plane and find that the data are inconsistent with the no-mixing hypothesis with a probability equivalent to 3.8 Gaussian standard deviations.
94 citations
TL;DR: In this article, the authors reported the observation of two narrow resonances consistent with states of orbitally excited (L=1) B_(s) mesons using 1 fb;(-1) of pp[over ] collisions at sqrt[s]=1.96 TeV collected with the Collider Detector at Fermilab II detector.
Abstract: We report the observation of two narrow resonances consistent with states of orbitally excited (L=1) B_(s) mesons using 1 fb;(-1) of pp[over ] collisions at sqrt[s]=1.96 TeV collected with the Collider Detector at Fermilab II detector at the Fermilab Tevatron. We use two-body decays into K- and B+ mesons reconstructed as B(+)-->J/psiK(+), J/psi-->mu(+)mu(-) or B(+)-->D[over ](0)pi(+), D[over ](0)-->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);(*))=5839.6+/-0.7 MeV/c;(2).
92 citations
TL;DR: The Bc± meson was observed through the decay Bc+→J/ ψπ±, in data corresponding to an integrated luminosity of 2.4fb-1 recorded by the Collider Detector at Fermilab II detector at the Fermielab Tevatron as discussed by the authors.
Abstract: The Bc± meson is observed through the decay Bc±→J/ ψπ±, in data corresponding to an integrated luminosity of 2.4fb-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 8σ. The mass of the Bc± meson is measured to be 6275.6±2.9(stat)±2.5(syst)MeV/c2. © 2008 The American Physical Society.
88 citations
TL;DR: In this paper, the authors search for new physics in over 300 exclusive final states in collision data collected in run II of the Fermilab Tevatron, and find no such significant indication of physics beyond the standard model.
Abstract: Data collected in run II of the Fermilab Tevatron are searched for indications of new electroweak scale physics. Rather than focusing on particular new physics scenarios, CDF data are analyzed for discrepancies with respect to the standard model prediction. A model-independent approach (Vista) considers the gross features of the data and is sensitive to new large cross section physics. A quasi-model-independent approach (Sleuth) searches for a significant excess of events with large summed transverse momentum and is particularly sensitive to new electroweak scale physics that appears predominantly in one final state. This global search for new physics in over 300 exclusive final states in $927\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$ of $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ reveals no such significant indication of physics beyond the standard model.
73 citations
TL;DR: In this paper, the authors performed a search for Bs-->mu+mu- and Bd-->mu +mu- decays in ppbar collisions at sqrt(s) = 1.96TeV using 2fb-1 of integrated luminosity collected by the Fermilab Tevatron Collider.
Abstract: We have performed a search for Bs-->mu+mu- and Bd-->mu+mu- decays in ppbar collisions at sqrt(s) = 1.96TeV using 2fb-1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron Collider. The observed number of Bs and Bd candidates is consistent with background expectations. The resulting upper limits on the branching fractions are B(Bs-->mu+mu-) mu+mu-) < 1.8X10^-8 at 95% C.L.
69 citations
TL;DR: In this paper, the three lepton and missing energy trilepton signature was used to search for chargino-neutralino production with 2.0 fb(-1) of integrated luminosity collected by the CDF II experiment at the Tevatron p (p) over bar collider.
Abstract: We use the three lepton and missing energy trilepton signature to search for chargino-neutralino production with 2.0 fb(-1) of integrated luminosity collected by the CDF II experiment at the Tevatron p (p) over bar collider. We expect an excess of approximately 11 supersymmetric events for a choice of parameters of the mSUGRA model, but our observation of 7 events is consistent with the standard model expectation of 6.4 events. We constrain the mSUGRA model of supersymmetry and rule out chargino masses up to 145 GeV/c(2) for a specific choice of parameters.
67 citations
TL;DR: In this paper, the authors performed a search for the branching fractions in the CDF II detector at the Fermilab Tevatron Collider and the observed number of candidates was consistent with background expectations.
Abstract: We have performed a search for ${B}_{s}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ and ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ decays in $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ using $2\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron Collider. The observed number of ${B}_{s}^{0}$ and ${B}^{0}$ candidates is consistent with background expectations. The resulting upper limits on the branching fractions are $\mathcal{B}({B}_{s}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})l5.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$ and $\mathcal{B}({B}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})l1.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$ at 95% C.L.
TL;DR: In this article, a measurement of the cross section for W-boson production in association with jets in p{bar p} collisions at {radical}s = 1.96 TeV is presented.
Abstract: We present a measurement of the cross section for W-boson production in association with jets in p{bar p} collisions at {radical}s = 1.96 TeV. The analysis uses a data sample corresponding to an integrated luminosity of 320 pb{sup -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 + {ge} n-jet sample (n = 1-4) we measure {sigma}(p{bar p} {yields} W + {ge} n-jet) x {Beta}(W {yields} e{nu}) with respect to the transverse energy E{sub T} of the nth-highest E{sub T} jet above 20 GeV, for a restricted W {yields} e{nu} 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.
TL;DR: In this article, the authors measured the cross sections of jet transverse momentum and multiplicity in p{bar p} collisions at {radical} s - 1.96 TeV with the upgraded Collider Detector at Fermilab in Run II, based on an integrated luminosity of 1.7 fb{sup -1}.
Abstract: Inclusive jet cross sections in Z/{gamma}* events, with Z/{gamma}* decaying into an electron-positron pair, are measured as a function of jet transverse momentum and jet multiplicity in p{bar p} collisions at {radical}s - 1.96 TeV with the upgraded Collider Detector at Fermilab in Run II, based on an integrated luminosity of 1.7 fb{sup -1}. The measurements cover the rapidity region |y{sup jet}| 30 GeV/c. Next-to-leading order perturbative QCD predictions are in good agreement with the measured cross sections.
TL;DR: In this paper, the W boson mass was measured using 200 pb{sup -1} of {radical}s = 1.96 TeV p{bar p} collision data taken with the CDF II detector.
Abstract: We describe a measurement of the W boson mass m{sub W} using 200 pb{sup -1} of {radical}s = 1.96 TeV p{bar p} collision data taken with the CDF II detector. With a sample of 63,964 W {yields} e{nu} candidates and 51,128 W {yields} {mu}{nu} candidates, we measure m{sub W} = [80.413 {+-} 0.034(stat.) {+-} 0.034 (sys.) = 80.413 {+-} 0.048] GeV/c{sup 2}. This is the single most precise m{sub W} measurement to date. When combined with other measured electroweak parameters, this result further constrains the properties of new unobserved particles coupling to W and Z bosons.
TL;DR: A measurement of the single-top-quark production cross section in 2.2 fb of pp collision data collected by the Collider Detector at Fermilab at sqrt[s]=1.96 TeV observes a signal consistent with the standard model prediction, but inconsistent with the background-only model.
Abstract: We report a measurement of the single top quark production cross section in 2.2 fb{sup -1} of p{bar p} collision data collected by the Collider Detector at Fermilab at {radical}s = 1.96 TeV. Candidate events are classified as signal-like by three parallel analyses which use likelihood, matrix element, and neural network discriminants. These results are combined in order to improve the sensitivity. We observe a signal consistent with the standard model prediction, but inconsistent with the background only model by 3.7 standard deviations with a median expected sensitivity of 4.9 standard deviations. We measure a cross section of 2.2{sub -0.6}{sup +0.7}(stat+sys) pb, extract the CKM matrix element value |V{sub tb}| = 0.88{sub -0.12}{sup +0.13}(stat + sys) {+-} 0.07(theory), and set the limit |V{sub tb}| > 0.66 at the 95% C.L.
TL;DR: In this paper, the first measurement of b-quark fragmentation fractions into bottom hadrons in Run II of the Tevatron Collider at Fermilab was described, based on a 360 pb{sup -1} sample of data collected with the CDF II detector in pp collisions at {radical}(s)=1.96 TeV.
Abstract: This paper describes the first measurement of b-quark fragmentation fractions into bottom hadrons in Run II of the Tevatron Collider at Fermilab. The result is based on a 360 pb{sup -1} sample of data collected with the CDF II detector in pp collisions at {radical}(s)=1.96 TeV. Semileptonic decays of B{sup 0}, B{sup -}, and B{sub s}{sup 0} mesons, as well as {lambda}{sub b}{sup 0} baryons, are reconstructed. For an effective bottom hadron p{sub T} threshold of 7 GeV/c, the fragmentation fractions are measured to be f{sub u}/f{sub d}=1.054{+-}0.018(stat){sub -0.045}{sup +0.025}(sys){+-}0.058(B), f{sub s}/(f{sub u}+f{sub d})=0.160{+-}0.005(stat){sub -0.010}{sup +0.011}(sys){sub -0.034}{sup +0.057}(B), and f{sub {lambda}{sub b}}/(f{sub u}+f{sub d})=0.281{+-}0.012(stat){sub -0.056}{sup +0.058}(sys){sub -0.087}{sup +0.128}(B), where the uncertainty B is due to uncertainties on measured branching ratios. The value of f{sub s}/(f{sub u}+f{sub d}) agrees within one standard deviation with previous CDF measurements and the world average of this quantity, which is dominated by LEP measurements. However, the ratio f{sub {lambda}{sub b}}/(f{sub u}+f{sub d}) is approximately twice the value previously measured at LEP. The approximately 2{sigma} discrepancy is examined in terms of kinematic differences between the two production environments.
TL;DR: In this paper, the mean lifetime τ = 2/(ΓL+ΓH) and the decay width difference ΔΓ=Γ L-Γ H of the light and heavy mass eigenstates of the Bs0 meson, BsL0 and BsH0, in Bs 0→J/ψ decays using 1.7fb-1 of data collected with the CDF II detector at the Fermilab Tevatron pp collider.
Abstract: We measure the mean lifetime τ=2/(ΓL+ΓH) and the decay-width difference ΔΓ=ΓL-ΓH of the light and heavy mass eigenstates of the Bs0 meson, BsL0 and BsH0, in Bs0→J/ψ decays using 1.7fb-1 of data collected with the CDF II detector at the Fermilab Tevatron pp collider. Assuming CP conservation, a good approximation for the Bs0 system in the standard model, we obtain ΔΓ=0.076-0.063+0. 059(stat)±0.006(syst)ps-1 and τ=1.52±0.04(stat)±0. 02(syst)ps, the most precise measurements to date. Our constraints on the weak phase and ΔΓ are consistent with CP conservation. © 2008 The American Physical Society.
TL;DR: In this paper, the authors presented the first measurement of the production cross section of a W boson with a single charm quark (c) in p{bar p} collisions at {radical}s = 1.96 TeV, using soft muon tagging of c jets.
Abstract: The authors present the first measurement of the production cross section of a W boson with a single charm quark (c) in p{bar p} collisions at {radical}s = 1.96 TeV, using soft muon tagging of c jets. In a data sample of {approx} 1.8 fb{sup -1}, recorded with the CDF II detector at the Fermilab Tevatron, they select events with W + 1 or 2 jets. They use the charge correlation between the W and the muon from the semileptonic decay of a charm hadron to extract the We signal. They measure {sigma}{sub Wc} (p{sub Tc} > 20 GeV/c, |{eta}{sub c}| < 1.5) x BR(W {yields} {ell}{nu}) = 9.8 {+-} 3.2 pb, in agreement with theoretical expectations.
TL;DR: In this paper, a search for narrow-width particles decaying to a top and antitop quark pair was conducted at Fermilab in Run II and upper limits on the cross section times branching ratio were presented.
Abstract: We report on a search for narrow-width particles decaying to a top and antitop quark pair. The data set used in the analysis corresponds to an integrated luminosity of 680 pb{sup -1} collected with the Collider Detector at Fermilab in Run II. We present 95% confidence level upper limits on the cross section times branching ratio. Assuming a specific top color-assisted technicolor production model, the leptophobic Z{prime} with width {Gamma}{sub Z{prime}} = 0.012M{sub Z{prime}}, we exclude the mass range M{sub Z{prime}} < 725 GeV/c{sup 2} at the 95% confidence level.
TL;DR: In this paper, the invariant mass spectrum of t (t) over bar pairs is compared to the expected superposition of standard model t(t) and non-t (t), over bar backgrounds, and a simple resonance model based on a sequential Z' boson.
Abstract: We search for evidence of resonant top quark pair production in 955 pb(-1) of p (p) over bar collisions at root s = 1: 96 TeV recorded with the CDF II detector at the Fermilab Tevatron. For fully reconstructed candidate t (t) over bar events triggered on leptons with large transverse momentum and containing at least one identified b-quark jet, we compare the invariant mass spectrum of t (t) over bar pairs to the expected superposition of standard model t (t) over bar, non-t (t) over bar backgrounds, and a simple resonance model based on a sequential Z' boson. We establish upper limits for sigma(p (p) over bar -> Z')center dot Br(Z' -> t (t) over bar) in the Z' mass interval from 450 GeV/c(2) to 900 GeV=c(2). A topcolor leptophobic Z' is ruled out below 720 GeV=c(2), and the cross section of any narrow Z'-like state decaying to t (t) over bar is found to be less than 0.64 pb at 95% C. L. for M-Z' above 700 GeV/c(2).
TL;DR: This work searches for pair production of doubly charged Higgs particles followed by decays into electron-tau (etau) and muon-tAU (mutau) pairs using data collected by the CDF II experiment, and sets an H+/- +/- lower mass limit of 114(112) GeV/c(2) at the 95% confidence level.
Abstract: We search for pair production of doubly charged Higgs particles (H+/- +/-) followed by decays into electron-tau (etau) and muon-tau (mutau) pairs using data (350 pb(-1) collected from [over]pp collisions at sqrt[s]=1.96 TeV by the CDF II experiment. We search separately for cases where three or four final-state leptons are detected, and combine results for exclusive decays to left-handed etau (mutau) pairs. We set an H+/- +/- lower mass limit of 114(112) GeV/c(2) at the 95% confidence level.
TL;DR: In this paper, the authors present the results of a search for pair production of a new heavy toplike quark decaying to a W boson and another quark using the Collider Detector at Fermilab II detector in run II of the Tevatron p (p) over bar collider.
Abstract: We present the results of a search for pair production of a new heavy toplike quark t' decaying to a W boson and another quark using the Collider Detector at Fermilab II detector in run II of the Tevatron p (p) over bar collider. Using a data sample corresponding to 760 pb(-1) of integrated luminosity, we fit the observed spectrum of total transverse energy and reconstructed t' quark mass to a combination of standard model processes and t' pair production. We see no evidence for t'(t) over bar' production, and we infer a lower limit of 256 GeV/c(2) on the mass of the t(') at 95% C.L. assuming standard strong couplings for the t'.
TL;DR: In this article, the authors search for a third generation vector leptoquark (VLQ3) that decays to a b quark and tau lepton using the CDF II detector and 320pb-1 of integrated luminosity from the Fermilab Tevatron.
Abstract: We search for a third generation vector leptoquark (VLQ3) that decays to a b quark and tau lepton using the CDF II detector and 320pb-1 of integrated luminosity from the Fermilab Tevatron Observing a number of events in agreement with standard model expectations, we obtain, assuming Yang-Mills (minimal) couplings, the most stringent upper limit on the VLQ3 pair production cross section of 344 fb (493 fb) and lower limit on the VLQ3 mass of 317GeV/c2 (251GeV/c2) at 95% CL © 2008 The American Physical Society
TL;DR: In this paper, a measurement of the correlated bb production cross section was presented, which was taken with the upgraded CDF detector (CDF II) at the Fermilab Tevatron collider.
Abstract: We present a measurement of the correlated bb production cross section. The data used in this analysis were taken with the upgraded CDF detector (CDF II) at the Fermilab Tevatron collider, and correspond to an integrated luminosity of 742 pb{sup -1}. We utilize muon pairs with invariant mass 5{ =}3 GeV/c and |{eta}|{ =}2 GeV/c and |y|{<=}1.3, we measure {sigma}{sub b{r_reversible}}{sub {mu}}{sub ,b{r_reversible}}{sub {mu}}=1549{+-}133 pb. We compare this result with theoretical predictions and previous measurements. We also report the measurement of {sigma}{sub c{r_reversible}}{sub {mu}}{sub ,c{r_reversible}}{sub {mu}}, a by-product of the study of the background to bb production.
TL;DR: The first top-quark mass measurement that uses a cross-section constraint to improve the mass determination is reported, made with a dilepton tt event candidate sample collected with the Collider Detector II at Fermilab.
Abstract: We report the first top-quark mass measurement that uses a cross-section constraint to improve the mass determination. This measurement is made with a dilepton tt event candidate sample collected with the Collider Detector II at Fermilab. From a data sample corresponding to an integrated luminosity of 1.2fb-1, we measure a top-quark mass of 170.7-3.9+4.2(stat)±2.6(syst) ±2.4(theory)GeV/c2. The measurement without the cross-section constraint is 169.7-4.9+5.2(stat)±3.1(syst)GeV/c2. © 2008 The American Physical Society.
TL;DR: In this article, the first measurement of the cross section for Z boson pair production at a hadron collider is reported. This result is based on a data sample corresponding to 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron.
Abstract: We report the first measurement of the cross section for Z boson pair production at a hadron collider. This result is based on a data sample corresponding to 1.9 fb{sup -1} of integrated luminosity from p{bar p} collisions at {radical}s = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. In the {ell}{ell}{ell}{prime}{ell}{prime} channel, we observe three ZZ candidates with an expected background of 0.096{sub -0.063}{sup +0.092} events. In the {ell}{ell}{nu}{nu} channel, we use a leading-order calculation of the relative ZZ and WW event probabilities to discriminate between signal and background. In the combination of {ell}{ell}{ell}{prime}{ell}{prime} and {ell}{ell}{nu}{nu} channels, we observe an excess of events with a probability of 5.1 x 10{sup -6} to be due to the expected background. This corresponds to a significance of 4.4 standard deviations. The measured cross section is {sigma}(p{bar p} {yields}ZZ) = 1.4{sub -0.6}{sup +0.7} (stat.+syst.) pb, consistent with the standard model expectation.
TL;DR: The first hadron collider search for heavy, long-lived neutralinos that decay via lightest neutralino to gamma gravitino in gauge-mediated supersymmetry breaking models was presented in this article.
Abstract: We present the results of the first hadron collider search for heavy, long-lived neutralinos that decay via lightest neutralino to gamma gravitino in gauge-mediated supersymmetry breaking models. Using an integrated luminosity of $570\pm34 pb^{-1}$ of $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV, we select $\gamma$+jet+missing transverse energy candidate events based on the arrival time of a high-energy photon at the electromagnetic calorimeter as measured with a timing system that was recently installed on the CDF II detector. We find 2 events, consistent with the background estimate of 1.3$\pm$0.7 events. While our search strategy does not rely on model-specific dynamics, we set cross section limits and place the world-best 95% C.L. lower limit on the neutralino mass of 101 GeV at lifetime = 5 ns.
TL;DR: A search for standard model Higgs bosons produced in association with W bosons from pp[over] collisions at sqrt[s]=1.96 TeV finds no excess lnubb[ over] production beyond the background expectation, and set 95% confidence level upper limits on the production cross section times branching fraction sigma(pp[over)-->WH)Br(H-->bb[over]).
Abstract: The authors report on the results of a search for standard model Higgs bosons produced in association with W bosons from p{bar p} collisions at {radical}s = 1.96 TeV. The search uses a data sample corresponding to approximately 1 fb{sup -1} of integrated luminosity. Events consistent with the W {yields} {ell}{nu} and H {yields} b{bar b} signature are selected by triggering on a high-p{sub T} electron or muon candidate and tagging one or two of the jet candidates as having originated from b quarks. A neural network filter rejects a fraction of tagged charm and light flavor jets, increasing the b-jet purity in the sample and thereby reducing the background to Higgs boson production. They observe no excess {ell}{nu}b{bar b} production beyond the background expectation, and they set 95% confidence level upper limits on the production cross section times branching fraction {sigma}(p{bar p} {yields} WH) {center_dot} Br(H {yields} b{bar b}) ranging from 3.9 to 1.3 pb, for specific Higgs boson mass hypotheses in the range 110 to 150 GeV/c{sup 2}, respectively.