Bulletin of the American Physical Society
2009 APS April Meeting
Volume 54, Number 4
Saturday–Tuesday, May 2–5, 2009; Denver, Colorado
Session X14: Higgs III |
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Sponsoring Units: DPF Chair: Raymond Brock, Michigan State University Room: Plaza Court 4 |
Tuesday, May 5, 2009 1:30PM - 1:42PM |
X14.00001: Search for a NMSSM $h \to aa \to \mu\mu\mu\mu$ at the LHC Sergey Senkin, James Pivarski, Alexander Belyaev, Alexei Safonov We investigate the feasibility of a search for a Next-to-MSSM Higgs boson ($h$) decaying to two light pseudoscalars ($a$) followed by the decay of the pseudoscalar to four muons. The NMSSM scenario escapes the stringent experimental limit on low Higgs mass by providing new decay modes, thereby lowering branching fractions relative to the conventional search channels. The analysis proposed in this contribution is sensitive to NMSSM Higgs production with the mass of the pseudoscalar in the range below twice the tau mass, even for relatively low integrated luminosity. The advantage of the four-muon mode is low background in the final state, which allows us to use Higgs bosons produced in gluon fusion, the dominant production mechanism at the LHC. We describe the analysis and calculate the amount of data needed for discovery and achievable exclusion limits in the case of no signal. [Preview Abstract] |
Tuesday, May 5, 2009 1:42PM - 1:54PM |
X14.00002: Effect of Relaxing $b$-quark Tagging Requirements in $WH$ Searches at CDF Chiara Ferrazza Significant increases in sensitivity have recently been obtained for Higgs searches at CDF based on increases in integrated luminosity and development of sophisticated analysis techniques. For a low mass standard model Higgs boson ($m_H <135$~GeV/$c^2$), production in association with a vector boson ($W$ or $Z$) with subsequent decays of $H \rightarrow b\overline{b}$ and either $W \rightarrow \ell \nu$, $Z \rightarrow \nu \nu$, or $Z \rightarrow \ell \ell$ lead to final states that provide the best separation between signal and backgrounds. Typically, some multivariate technique is applied to the subset of events in which at least one of the $b$-quark jets is identified by the presence of a displaced, secondary vertex. Here, we present results of studies showing the potential gains in sensitivity that can be obtained by relaxing requirements used to identify these secondary vertices. [Preview Abstract] |
Tuesday, May 5, 2009 1:54PM - 2:06PM |
X14.00003: ABSTRACT WITHDRAWN |
Tuesday, May 5, 2009 2:06PM - 2:18PM |
X14.00004: Search for WH Production at $\sqrt{s}$ = 1.96 Te V with 2.7 fb$^{-1}$ of Data Qichun Xu A search for WH production in $p\bar p$ collisions at a center of mass energy of $\sqrt{s}$ = 1.96 TeV is presented. The data correspond to an integrated luminosity of 2.7 fb$^{-1}$ as accumulated by the D0 experiment. Events containing one lepton, missing transverse energy and one or two b-tagged jets are analysed using advanced analysis techniques (neural network and matrix element discriminants) to enhance the potential W H signal over the standard model background. Recent improvements to the sensitivity will be discussed. [Preview Abstract] |
Tuesday, May 5, 2009 2:18PM - 2:30PM |
X14.00005: Search for Associated Production of Z and Higgs Bosons in the $ee bb$ Final State in $p\bar{p}$ Collisions at $\sqrt{s}$=1.96 TeV Michael Kirby We present a search for a low mass standard model Higgs boson produced in association with a $Z$ boson decaying to two electrons at a center-of-mass energy of $\sqrt{s}=$1.96~TeV with the D0 detector at the Fermilab Tevatron collider. The search is performed in events containing one or two b-tagged jets with of order 4~fb$^{-1}$ of data. As well as the inclusion of the full data set, recent improvements to the sensitivity will be discussed. [Preview Abstract] |
Tuesday, May 5, 2009 2:30PM - 2:42PM |
X14.00006: A Combined Search for $WH$ Production in the $\ell \nu b\overline{b}$ Decay Channel at CDF Martin Frank Two independent methods are being used to search for a standard model Higgs boson produced in association with a $W$ boson using data collected with the CDF~II detector from $p\overline{p}$ collisions at $\sqrt{s} = 1.96$~TeV. The searches are performed using events in the $\ell \nu b\overline{b}$ final state from a data sample corresponding to an integrated luminosity of 2.7 fb$^{-1}$. The two search methods differ in terms of multivariate techniques used to separate signal from background: one uses an artificial neural network and the other uses a boosted decision tree with additional inputs dervived from matrix element calculations. We present the method used to combine the results of these searches and its effect on the overall sensitivity. In the absence of an observed excess in data, we set an upper limit on the production rate times branching ratio. [Preview Abstract] |
Tuesday, May 5, 2009 2:42PM - 2:54PM |
X14.00007: Search for a Light Higgs Boson in Radiative $\Upsilon$ Decays Arafat Mokhtar We have collected $\sim 30~\mathrm{fb}^{-1}$ of data with the {\it B{\footnotesize A}B{\footnotesize AR}} detector at the PEP- II asymmetric $e^+e^-$ collider operating at a center-of-mass energy of 10.355 GeV. This data sample contains approximately 122 million $\Upsilon(3S)$ candidates. We will present a search for light Higgs in the decays $\Upsilon(3S)\to\gamma A^0 $. We will present the techniques and methods, as well as the results and conclusions from this search. [Preview Abstract] |
Tuesday, May 5, 2009 2:54PM - 3:06PM |
X14.00008: Search for Dimuon Decays of a Light Scalar in Radiative Transitions $\Upsilon\to\gamma A^0$ Erik Petigura We report on a search for evidence of a light Higgs boson in the radiative decays of the narrow $\Upsilon$ resonances: $\Upsilon\to\gamma A^0$, $A^0\to\mu^+\mu^-$, using data collected by the {\it B{\footnotesize A}B{\footnotesize AR}} detector. Such an object appears in extensions of the Standard Model, where a light CP-odd Higgs boson naturally couples strongly to $b$-quarks. [Preview Abstract] |
Tuesday, May 5, 2009 3:06PM - 3:18PM |
X14.00009: Search for Lepton-Flavor Violation in Narrow $\Upsilon$ Resonance Decays Benjamin Hooberman Charged lepton-flavor violating processes are extremely rare in the Standard Model, but they are predicted to occur in several beyond-the-Standard Model theories, including Supersymmetry or models with leptoquarks or compositeness. We present searches for such processes in narrow $\Upsilon$ resonance decays. From a sample of 117 million $\Upsilon(3S)$ decays recorded with the {\it B{\footnotesize A}B{\footnotesize AR}} detector, we place upper limits on the branching fractions ${\cal B}(\Upsilon(3S) \rightarrow e \tau) < 5.0\times 10^{-6}$ and ${\cal B}(\Upsilon(3S) \rightarrow \mu \tau) < 4.1\times 10^{-6}$ at 90\% confidence level. These results are used to place lower limits on the mass scale of beyond-the-Standard Model physics contributing to lepton-flavor violating decays of the $\Upsilon(3S)$. [Preview Abstract] |
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