Bulletin of the American Physical Society
2006 APS April Meeting
Saturday–Tuesday, April 22–25, 2006; Dallas, TX
Session Q13: Particle Searches II |
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Sponsoring Units: DPF Chair: Beate Heinemann, University of Liverpool Room: Hyatt Regency Dallas Cumberland G |
Monday, April 24, 2006 1:30PM - 1:42PM |
Q13.00001: Minimal Supergravity with m$_0^2 <$ 0 Bryan Smith, Jonathan Feng, Arvind Rajaraman We extend the parameter space of minimal supergravity to negative values of m$_0^2$, the universal scalar mass parameter defined at the grand unified scale. After evolving to the weak scale, all scalars can be non-tachyonic with masses consistent with collider constraints. This region of parameter space is typically considered excluded by searches for charged dark matter, since the lightest standard model superpartner is a charged slepton. However, if the gravitino is the lightest supersymmetric particle, the charged slepton decays, and this region is allowed. This region provides qualitatively new possibilities for minimal supergravity, including spectra with light sleptons and very heavy squarks, and models in which the lightest slepton is the selectron. We show that the m$_0^2 <$ 0 region is consistent with low energy precision data and discuss its implications for particle colliders. These models may provide signals of supersymmetry in even the first year of operation at the Large Hadron Collider. [Preview Abstract] |
Monday, April 24, 2006 1:42PM - 1:54PM |
Q13.00002: Search for Multi-photon Signatures in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV Oleksiy Atramentov A preliminary cross section for the inclusive multiphoton production is presented, as measured by the Run II D\O\ detector at the Fermilab Tevatron $p\bar{p}$ collider. Photon candidates with transverse momenta greater than 15 GeV$/c$ and within the pseudorapidity of $|\eta| < 2.5$ are considered. Selection criteria for photon candidates as well as the estimation of background contributions from QCD and EW processes are presented. Event topologies with $\gamma\gamma\gamma+X$ in the final state which are relevant for fermiophobic Higgs boson searches in two Higgs doublet and triplet models are emphasized. Preliminary limits on the mass of fermiophobic Higgs boson are set. [Preview Abstract] |
Monday, April 24, 2006 1:54PM - 2:06PM |
Q13.00003: Search for Randall-Sundrum excitations of gravitons decaying into two photons for CMS at LHC Vladimir Litvin, H. Newman, M.-C. Lemaire The CMS detector discovery potential for resonant production of the massive Kaluza - Klein excitations predicted by the Randall- Sundrum model is studied. Full simulation and reconstruction are used to study the diphoton decay of Randall-Sundrum gravitons. For an integrated luminosity of 30 fb${}^{-1}$, the diphoton decay of Randall- Sundrum gravitons can be discovered at the 5$\sigma$ level for masses up to 1.61 ${}TeV/c^2$ for the case of weak coupling between graviton excitations and Standard model particles ($c=0.01$). Heavier resonances can be detected if the coupling is larger ($c=0.1$), with a mass reach of 3.95 ${}TeV/c^2$. [Preview Abstract] |
Monday, April 24, 2006 2:06PM - 2:18PM |
Q13.00004: Sensitivity to Contact Interactions from Quark Compositeness at CMS Selda Esen, Robert Harris CMS will measure dijets in proton-proton collisions at $\sqrt{s} =14$ TeV. The angular distribution of dijets as a function of invariant mass is sensitive to a contact interaction among quarks that could arise if quarks are not pointlike particles. The sensitive part of the angular distribution is measured by the dijet ratio: the number of dijet events with $|\eta|<0.5$ divided by the number of dijet events with $0.5<|\eta|<1.0$. As a function of dijet invariant mass, we present estimates of the dijet ratio for both the QCD background and a contact interaction signal. For integrated luminosities of 100 pb$^{-1}$, 1 fb$^{-1}$ and 10 fb$^{-1}$, we present CMS capability to exclude or discover contact interactions from quark compositeness. [Preview Abstract] |
Monday, April 24, 2006 2:18PM - 2:30PM |
Q13.00005: Sensitivity to Dijet Resonances at CMS Kazim Gumus, Nural Akchurin, Selda Esen, Robert Harris CMS will measure the dijet mass spectrum in proton-proton collisions at $\sqrt{s}=14$ TeV and will search for narrow resonances. For an integrated luminosity of 1 fb$^{-1}$ the measured dijet mass spectrum of the QCD background is expected to extend from 0.3 to 6 TeV for jet $|\eta|<1$. For integrated luminosities of 100 pb$^{-1}$, 1 fb$^{-1}$ and 10 fb$^{-1}$, we present CMS capability to exclude or discover several models of narrow dijet resonances: excited quarks, axigluons or colorons, E6 diquarks, color octet techirhos, Randall-Sundrum gravitons, and new electoweak gauge bosons W' and Z'. [Preview Abstract] |
Monday, April 24, 2006 2:30PM - 2:42PM |
Q13.00006: Search for Heavy Right-handed Quarks in the Electron-Muon+X channel Marshall Collin Wolfe We present a search for new, heavy objects in the electron-muon channel at CDF using 300~$pb^{-1}$ of data. To probe the reach of the search, we set a cross section limit on a 300 GeV right handed down type quark predicted by Bjorken, Pakvasa and Tuan. [Preview Abstract] |
Monday, April 24, 2006 2:42PM - 2:54PM |
Q13.00007: Search for long-lived neutral particles Todd Admas We have performed a search for a relatively long-lived neutral particle using the D\O\ experiment. The particle is allowed to decay significantly away from the production (at least 5 cm), but still within the inner tracking detector. We search for a decay to two muons and missing energy, using the muon tracks to identify the displaced vertex. Background is found to be small and estimated from the data. We present the results of our search and a comparison to the limit set by NuTeV for dimuon events in the 3-15 GeV mass region. [Preview Abstract] |
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