Bulletin of the American Physical Society
2009 APS April Meeting
Volume 54, Number 4
Saturday–Tuesday, May 2–5, 2009; Denver, Colorado
Session D9: Mini-Symposium on Standard Model and Higgs Physics |
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Sponsoring Units: DPF Chair: Daniela Bortoletto, Purdue University Room: Governor's Square 11 |
Saturday, May 2, 2009 3:30PM - 4:06PM |
D9.00001: Status and prospects for Higgs searches at the Tevatron Invited Speaker: The Tevatron has delivered more than 5.5 inverse femtobarns of proton-antiproton collisions to the DZero and CDF experiments. The two collaborations are developing novel advanced analyses techniques to search for the Higgs boson. The search exploits different production mechanisms for the Higgs boson according to its mass. The analyses search for the Higgs boson produced in association with either a W or Z boson for MH $<$ 135 GeV/$c^{2}$ where the Higgs boson is expected to decay primarily to a bottom-antibottom quark pair. In the higher mass range, 130 $<$ MH $<$ 200 GeV/$c^{2}$, the analyses search for the Higgs Boson produce singly and decaying to a pair of vector bosons, primarily WW. This talk reviews the current status of the Tevatron searches and presents the current production cross section limits, including the combined limits using the different search channels and the results from both CDF and DZero. The prospects for future improvements based on projected data sample sizes and novel experimental techniques are also discussed. [Preview Abstract] |
Saturday, May 2, 2009 4:06PM - 4:18PM |
D9.00002: Search for Associated Production of W and Higgs Bosons in the all Hadronic Decay Mode in $p\bar{p}$ Collisions at $\sqrt{s}$=1.96 TeV Justace Clutter We present a search for a low mass standard model Higgs Boson, produced in association with a $W$ boson, in the all hadronic decay channel at a center-of-mass energy of $\sqrt{s}=$1.96~TeV, using 1~fb$^{-1}$ of data collected with the D0 detector at the Fermilab Tevatron collider. The Higgs boson is required to decay to two $b$-quarks and the $W$ boson to two light quarks. This channel is potentially very powerful but is extremely challenging because of the large multijet background. A two dimensional fit to the invariant mass of the two $b$-quark jets and the invariant mass of the remaining two light quark jets is explored as a technique to determine a limit on the production cross section of the Standard Model Higgs boson. [Preview Abstract] |
Saturday, May 2, 2009 4:18PM - 4:30PM |
D9.00003: Search for $ZH$ in the $\ell \ell b\overline{b}$ Final State using a Neural Network Discriminant at CDF Shalhout Shalhout We report on a search for a Higgs boson produced in association with a $Z$ boson using 2.7 fb$^{-1}$ of CDF~II data collected from $p\overline{p}$ collisions at $\sqrt{s} =$~1.96~TeV based on the $\ell \ell b\overline{b}$ final state. To maximize signal acceptance we impose loose lepton and $b$-quark jet identification requirements. We correct the measured energies of the jets using an artificial neural network which assigns any observed missing transverse energy between the two jets. In order to maintain signal efficiency and improve signal discrimination, we employ an additional neural network trained to discriminate events based on differences in the event kinematics for $ZH$ events and those for the main $Z$ plus jets and $t\overline{t}$ backgrounds. We set 95\% Confidence Level upper limits on the production cross section times branching ratio for potential Higgs boson masses between 100 and 150~GeV/$c^2$. [Preview Abstract] |
Saturday, May 2, 2009 4:30PM - 4:42PM |
D9.00004: Search for the Higgs Boson in $WW^{(*)}\to \ell\nu\ell\nu-$ Decays in $p\bar{p}$ Collisions at $\sqrt{s}$=1.96 TeV Bjoern Penning We present a search for the standard model Higgs boson produced via the $H\to WW^{(*)}\to \ell\nu\ell\nu$ process at a center-of-mass energy of $\sqrt{s}=$1.96~TeV with the D0 detector at the Fermilab Tevatron collider. A Higgs particle with a mass greater than 140 GeV primarily decays into a pair of W-bosons and the leptonic decay channels of the W provide a clear signature. This channel is one of the most sensitive to the Higgs at the Tevatron. As well as the inclusion of the full data set, up to 4~fb$^{-1}$, recent improvements to the sensitivity will be discussed. [Preview Abstract] |
Saturday, May 2, 2009 4:42PM - 4:54PM |
D9.00005: Improved search for a Higgs boson in the $H \rightarrow \tau \tau$ decay channel at CDF Andrey Elagin We present an improved search for a Higgs boson in the channel $gg \rightarrow H \rightarrow \tau \tau$ based on data collected with the CDF detector at the Tevatron collider. Improvements include optimization of the signal fitting procedure and increased signal acceptance resulting from a better identification technique for hadronic $\tau$ lepton decays. The latter is based on a likelihood-based algorithm which gives superior energy resolution, better definition of other identification variables such as jet invariant mass, and a direct estimate of the uncertainty in the energy measurement for each individual hadronic $\tau$ candidate. [Preview Abstract] |
Saturday, May 2, 2009 4:54PM - 5:06PM |
D9.00006: Search for Associated Production of Z and Higgs Bosons in $\nu\nu bb$ Final States in $p\bar{p}$ Collisions at $\sqrt{s}$=1.96 TeV Gabriel Facini We present a search for a low mass standard model Higgs boson produced in association with a $Z$ boson decaying invisibly into a pair of neutrinos at a center-of-mass energy of $\sqrt{s}=$1.96~TeV with the D0 detector at the Fermilab Tevatron collider. The final state is characterised by the presence of two b-tagged jets from the Higgs boson decay and a large imbalance in the transverse energy of the event. This channel is very powerful because of the large $Z\to \nu\nu$ branching ratio, but is experimentally very challenging because of the large QCD backgrounds and absence of visible leptons in the final state. As well as the inclusion of the full data set, up to 4~fb$^{-1}$, recent improvements to the sensitivity will be discussed. [Preview Abstract] |
Saturday, May 2, 2009 5:06PM - 5:18PM |
D9.00007: Combined Upper Limit on Standard Model Higgs Boson Production at D0 in $p\bar{p}$ Collisions at $\sqrt{s}$=1.96 TeV Michael Kirby We present the combination of the searches for the Standard Model Higgs boson at a center-of-mass energy of $\sqrt{s}=$1.96~TeV, using up to 4~fb$^{-1}$ of data collected with the D0 detector at the Fermilab Tevatron collider. The major contributing processes include associated production ($WH\to l\nu bb$, $ZH\to\nu\nu bb$, $ZH\to ll bb$, and $WH\to WWW^{(*)}$) and gluon fusion ($gg\to H\to WW^{(*)}$). The significant improvements across the full mass range resulting from the larger data sets, improved analyses and inclusion of additional channels are discussed. [Preview Abstract] |
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