Bulletin of the American Physical Society
APS April Meeting 2013
Volume 58, Number 4
Saturday–Tuesday, April 13–16, 2013; Denver, Colorado
Session T11: Searches II |
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Sponsoring Units: DPF Chair: Bob Bernstein, Fermi National Accelerator Laboratory Room: Governor's Square 17 |
Monday, April 15, 2013 3:30PM - 3:42PM |
T11.00001: Search for invisible decays of low-mass Higgs bosons at BaBar Mark Derdzinski We search for a light scalar particle produced in single-photon decays of the $\Upsilon(2S)$ and $\Upsilon(3S)$ resonances through the process $\Upsilon\to \gamma + A^0$, $A^0 \to \hbox{invisible}$. Such an object appears in supersymmetric extensions of the Standard Model, such as NMSSM, where a light $CP$- odd Higgs boson naturally couples strongly to $b$-quarks. If in addition there exist a light stable neutralino, decays of $A^0$ could be preferentially to an invisible final state. We search for events with a single high energy photon and a large missing energy and momentum, consistent with a 2-body decay of $\Upsilon$. [Preview Abstract] |
Monday, April 15, 2013 3:42PM - 3:54PM |
T11.00002: Results of a Search for a CP-Odd Light Higgs in $\tau$-Pair Decays of the $\Upsilon$(1S) at Belle Jamal Rorie We conduct a search for a CP-odd light Higgs, $A^0$, in a sample of $(102\pm2) \times10^{6}$ $\Upsilon(1S)$ by looking for $\Upsilon(1S) \rightarrow \gamma A^0$ radiative decays with $A^0\rightarrow\tau^+\tau^-$. No significant evidence of such decays is found. We set an 90\% confidence level upper limit on $ BR(\Upsilon(1S)\rightarrow\gamma A^0) \times BR(A^0\rightarrow\tau^+\tau^-)$ between $4.0\times10^{-6}$ to $4.5\times10^{-5}$ for $A^0$ masses ranging from 3.6 GeV to 9.3 GeV. [Preview Abstract] |
Monday, April 15, 2013 3:54PM - 4:06PM |
T11.00003: Search for $W^\prime$ bosons through decays to boosted top-jets Zack Sullivan, Daniel Duffty We propose an alternate model-independent method to search for $W^\prime$ bosons at the Large Hadron Collider by looking at dijets where one jet is identified as a boosted top-jet. Performing a detector simulated signal and background study, we demonstrate that the reach in effective coupling $g^\prime$ is improved over existing analysis methods by a factor of 5 for $W^\prime$ masses below 1.8 TeV, and extend the reach in mass up to 2.5 TeV in the 8 TeV data sample. In order to reach the maximum sensitivity, we describe a previously unexplored set of backgrounds involving muon tagging of high energy $b$ jets and standard model backgrounds to top-tag jets that we simulate. We propose a series of data-driven samples that might be used to measure the efficiencies for these new backgrounds in the LHC data. [Preview Abstract] |
Monday, April 15, 2013 4:06PM - 4:18PM |
T11.00004: New Simulations of ATLAS Data for the 8TeV Upgrade Arya Afshari The recent Large Hadron Collider (LHC) beam upgrade in center-of-mass energy from s $=$ 7TeV to s $=$ 8TeV required upgrades to the existing event generators for simulation of data. Data simulation using known theory is compared to processed data from the ATLAS detector in order to ensure the calibration of the detector. The upgrade in the Pythia6 to Pythia8 event generator was validated, as well as the various parton distribution functions (PDF's) CTEQ, MRST, and MSTW. A Monte Carlo (MC) simulation for the excited W* was created at various resonant energies using Pythia6 with the CTEQ PDF and one for each PDF in Pythia8. Various dijet parameters were compared within the PDF's as well as the Fchi variable against the QCD background. Inclusive to the work done, two different methods were employed in finding the mass of the excited boson W*. This work is from the authors' summer 2012 research at CERN. [Preview Abstract] |
Monday, April 15, 2013 4:18PM - 4:30PM |
T11.00005: Maximizing Gauge Boson Identification Reaches in $e^{+}e^{-}$ Collisions via Proper Selection of Beam Polarization Ali Bagneid Most extensions of the standard model predict the existence of extra neutral gauge bosons. These particles can manifest themselves in $e^{+}e^{-}$ collisions via small deviations of various physical observables from the corresponding standard model values. We considered leptonic observables and showed that the size of these deviations can be controlled by the proper selection of the polarizations of the positron and electron beams. We determined, for a given extension, a single set of beam polarization so that if this set is employed in measuring all considered leptonic observables, it produces maximum gauge boson identification reaches. [Preview Abstract] |
Monday, April 15, 2013 4:30PM - 4:42PM |
T11.00006: ABSTRACT WITHDRAWN |
Monday, April 15, 2013 4:42PM - 4:54PM |
T11.00007: UED generalized with bulk masses and brane localized terms Kyoungchul Kong, Thomas Flacke, Seong Chan Park We present a generalized universal extra dimensional model with KK-parity in the presence of the fermion-bulk masses and boundary-localized kinetic terms, which are generally allowed by symmetries of five dimensional gauge theory. [Preview Abstract] |
Monday, April 15, 2013 4:54PM - 5:06PM |
T11.00008: Search for Quark and Lepton Compositeness in the Dimuon Final State in p-p Collisions using the CMS Experiment Chamath Kottachchi Kankanamge Don, Pramod Lamichhane, Paul Karchin, Leonard Spiegel Discovery of the last missing piece in the Standard Model of particle physics, the Higgs Boson, will leave many unanswered questions in particle physics. Compositeness of quarks and leptons with more basic constituents, known as preons, is a possible new type of physics which can be described by a four-fermion contact interaction. Using the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC), we study the invariant mass spectrum of oppositely charged muon pairs using data collected in year 2012 at 8 TeV collision energy and integrated luminosity of approximately 20/fb. We compare the observed mass spectrum with the full simulation Monte Carlo prediction for a contact interaction using a Left-left Isoscalar Model of quark compositeness with compositeness energy scale Lambda. [Preview Abstract] |
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