Bulletin of the American Physical Society
2005 APS April Meeting
Saturday–Tuesday, April 16–19, 2005; Tampa, FL
Session U8: Searches for Supersymmetry II |
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Sponsoring Units: DPF Chair: Carlos Wagner, Argonne/University of Chicago Room: Marriott Tampa Waterside Room 4 |
Monday, April 18, 2005 3:30PM - 3:54PM |
U8.00001: SUSY with Non-universal Higgs Masses Azar Mustafayev, Howard Baer, Alexander Belyaev, Stefano Profumo, Xerxes Tata In supersymetric models with gravity-mediated SUSY breaking, universality of soft SUSY breaking scalar masses is motivated by the need to suppress unwanted flavor changing or $CP$ violating processes. The motivation, however, does not apply to soft breaking Higgs masses, which may in general have independent masses from matter scalars at the GUT scale. We explore the consequences of both the one-parameter and two-parameter non-universal Higgs mass models (NUHM1 and NUHM2). In both NUHM1 and NUHM2 models, the A-funnel and higgsino dark matter annihilation regions can be realized for any $\tan\beta$ values, unlike the case with the mSUGRA model. We examine the parameter space of NUHM models with respect to $\Omega_{CDM}h^2$, $BF(b\to s\gamma )$ and $(g-2)_\mu$. The most favored regions tend to have a small, positive Higgs mass parameter $\mu$, and a mixed gaugino/higgsino LSP. These regions of parameter space can give rise to observable trilepton rates at the Fermilab Tevatron collider, and robust signal rates at the CERN LHC and a TeV-scale linear $e^+e^-$ collider. [Preview Abstract] |
Monday, April 18, 2005 3:54PM - 4:06PM |
U8.00002: Search for R-parity violating supersymmetry in multilepton events with the D\O\ detector Daniela Kaefer Supersymmetric models which do not assume the conservation of R-parity involve additional lepton or baryon number violating trilinear couplings. In this analysis, mass limits on neutralinos and charginos are given for the cases of lepton number violating couplings $\lambda_{122}$ and $\lambda_{121}$ which connect leptons of the first and second generations, i.e. electrons and muons as well as their corresponding neutrinos. The data sample, recorded from April 2002 until September 2004 with the D\O\ experiment at the Fermilab Tevatron collider, corresponds to an integrated luminosity of $\sim 350$ pb$^{-1}$. The search concentrates on final states with at least three charged leptons, electrons or muons. In addition, results are reported from a similar search for final states with two electrons and a $\tau$-lepton, relevant for a $\lambda_{133}$ coupling. [Preview Abstract] |
Monday, April 18, 2005 4:06PM - 4:18PM |
U8.00003: Search for R-Parity Violating SuperSymmetry in the Four-Lepton Final State at the Tevatron Alon Attal Assuming a long lifetime for the lightest supersymmetric particle and R-parity violation, a scenario can be constructed where four or more leptons are present in the final state in proton-antiproton collisions at $\sqrt{s}$ 1.96 TeV at the Tevatron. We investigate the sensitivity of this signature in the minimal supergravity framework and compare it to standard model predictions. A blind analysis is done on 300 pb$^{-1}$ of data collected by the CDF detector and is used to constrain the SUSY parameter space. [Preview Abstract] |
Monday, April 18, 2005 4:18PM - 4:30PM |
U8.00004: Search for supersymmetric top and bottom squarks in the $\tilde{t}\to c\chi$ and $\tilde{b}\to b\chi$ channels with the D\O\ detector Mansoora Shamim Supergravity inspired models suggest the existence of light supersymmetric partners of the third generation quarks: a light stop for small or moderate values of $\tan\beta$, a light sbottom for large $\tan\beta$. If the stop or sbottom is the next-to-lightest supersymmetric particle, the expected decay channels are $\tilde{t}\to c\chi$ and $\tilde{b}\to b\chi$, respectively. Pair production of stops or sbottoms in $p\bar{p}$ collisions will therefore lead to the signature of two acoplanar heavy flavor jets and missing transverse energy. The search for such final states in data collected at a center-of-mass energy of 1.96\,TeV by the D\O\ detector at the Fermilab Tevatron collider will be presented, with particular emphasis on the heavy-flavor tagging techniques used. [Preview Abstract] |
Monday, April 18, 2005 4:30PM - 4:42PM |
U8.00005: Search for Production of Scalar Top Quark Pairs in the Opposite-sign Di-lepton Final State at the Tevatron Alexei Sedov, Oscar Gonzalez-Lopez Using the CDF detector we search for the pair production of the supersymmetric partner of the top quark (stop quark), in proton-antiproton collisions at $\sqrt{s} = 1.96$ TeV at the Tevatron. Assuming that the stop quark is lighter than the top quark, and R-parity is conserved, the search considers that the stop quark decays into a b-jet, a lepton and an undetected sneutrino. Preliminary results are presented using data collected with the CDF dilepton triggers, and requiring the presence in the final state of two opposite-sign leptons, hadronic jets and missing transverse energy. The analysis is based on an integrated luminosity of about $300$ pb$^{-1}$. [Preview Abstract] |
Monday, April 18, 2005 4:42PM - 4:54PM |
U8.00006: Search for Supersymmetric Top Quark Production with R-parity Violating Decays at CDF Vadim Khotilovich We perform a search for the supersymmetric partner of the top quark (stop) using an integrated luminosity about 200 pb$^{-1}$ of data collected with the CDF Run 2 detector in proton-antiproton collisions at $\sqrt{s} = 1.96$ TeV. Within a framework of R-parity violation where the stop decays into a $\tau$ lepton and a bottom quark, pair-produced stop quarks result in the final state of one electron or muon (from a leptonic $\tau$ decay), one hadronic tau decay, and two jets. With no excess of events observed over the Standard Model prediction, we set an upper limit on the production cross- section and a lower limit on the stop mass. These limits are also directly applicable to third generation scalar leptoquarks decaying to $\tau$ lepton and a bottom quark. [Preview Abstract] |
Monday, April 18, 2005 4:54PM - 5:06PM |
U8.00007: Search for Stop Quark Production in GMSB SUSY Models via $p\bar{p} \to \tilde{t} \bar{\tilde{t}}$ where $\tilde{t} \to \tilde{\chi^0} + c \to \tilde{G} + c + \gamma$ at CDF Annelise Malkus Using about 400 pb$^{-1}$ of CDF Run II data, we search for stop quarks, the supersymmetric counterpart to the top quark. Gauge Mediated Symmetry Breaking (GMSB) SUSY models predict the process, $p\bar{p} \to \tilde{t} \bar{\tilde{t}}$ where $\tilde{t} \to \tilde{\chi^0} + c \to \tilde{G} + c + \gamma$, resulting in a final state of two jets, two photons and missing transverse energy. This is the first time this signature has been investigated. If we find no signal, we will set constraints on the stop quark mass in these models. [Preview Abstract] |
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