Bulletin of the American Physical Society
2011 Annual Meeting of the California-Nevada Section of the APS
Volume 56, Number 14
Friday–Saturday, November 11–12, 2011; Menlo Park, California
Session F2: High Energy/Accelerator Physics |
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Chair: Ken Ganezer, CSU Dominguez Hills Room: Bldg 48 - ROB Redwood C/D |
Saturday, November 12, 2011 1:00PM - 1:12PM |
F2.00001: Experimental Analysis of Gaseous Chambers for the ATLAS Muon sub-detector Upgrade R\&D Emmanuel Angulo, Joerg Wotschack CERN, the world's largest particle accelerator facility, has begun its ambitious Large Hadron Collider (LHC) program which is and will remain as the world energy frontier until at least 2030. ATLAS, one of the LHC experiments designed to search for new physics, has been taking data for two years. ATLAS has been investigating the necessary changes to its sub-detectors to withstand much higher instantaneous luminosity and to operate after 3000 fb-1 of integrated data. The goal is to achieve the same or better performance (spatial resolution, etc.) despite the large increase in event rate and final integrated dose. The current ATLAS Muon sub-detector will not be able to handle the increased luminosity of a factor of ten. This makes it necessary to replace the current muon sub-detector by possible new gaseous chambers that push their performance to limits never tested before. This talk will focus on the different lab experiments performed at CERN, including a test beam run, and the exciting results on two of the latest chamber prototypes (R19M and R19G) developed by the ATLAS Muon detector upgrade R\&D team. This is the research project the author did at CERN during summer 2011. [Preview Abstract] |
Saturday, November 12, 2011 1:12PM - 1:24PM |
F2.00002: Improved Simulations for New Physics Searches at ATLAS Navid Rad ATLAS experiment at the Large Hadron Collider (LHC) of CERN is designed to make new discoveries in particle physics. Some of the possible findings are the Higgs boson, supersymmetry (SUSY), extra spatial dimensions, micro-black holes and a whole zoo of other exotic possibilities. However, before looking for these new possibilities, one needs to verify our current theories and understanding of physics at the level of Quantum ChromoDynamics (QCD). Since HEP experiments look for rare events, the amount of data that needs to be analyzed is astronomical. Also the fact that the comparison of the experiment to data is often done by using event generators such as Pythia makes the process of analysis extremely time consuming. The purpose of this research project is to utilize and develop additional software tools in order to decrease the time and computing power required for calculations done at ATLAS. The APPLgrid software package allows for quick calculations with any parton distribution function (PDF) which could take only a few milliseconds where as the same calculation using Pythia could take weeks for each PDF. The results that will be shown in this presentation are some sample calculations done by APPLgrid and also the comparison with similar calculations done by Pythia at the level of QCD and beyond. This is a research project the author did at CERN during the summer of 2011. [Preview Abstract] |
Saturday, November 12, 2011 1:24PM - 1:36PM |
F2.00003: Jets in ATLAS Data from Fresno's Tier 3 Computing System Arya Afshari California State University, Fresno is the only CSU campus on the ATLAS experiment at the Large Hadron Collider (LHC) of the European Organization for Nuclear Research (CERN). Fresno's Tier 3 cluster is part of the ATLAS Grid Computing system which stores part of ATLAS data ($\sim $10 PB per year) and allows our students to analyze raw data and generate Monte Carlo events. The proton-proton collisions recorded by the ATLAS detector are analyzed in order to identify sprays of new particles (known as jets). The jets are characterized by their transverse momentum, angle which the cone axis makes with respect to the beam axis (rapidity), and the angle at which the cone encircles the beam axis (phi). When analyzing these jets in raw data, it is extremely difficult to distinguish jets created by possible new physics processes from jets created by known physics processes (QCD backgrounds). Monte Carlo simulations do not have such QCD backgrounds and are thus essential in calibrating the detector with known physics. We use ROOT to find the transverse momentum, rapidity, and phi of the jets. The jet with the greatest transverse momentum is significant to us because it is more likely to contain new physics. Having found the jet with the highest transverse momentum from the simulations, we know where to look in the raw data for potential new physics. These ATLAS Monte Carlo simulations of jets are from the authors' summer 2011 work at CERN. [Preview Abstract] |
Saturday, November 12, 2011 1:36PM - 1:48PM |
F2.00004: Plasma Wakefield Acceleration Experiments at FACET Michael Litos, Mark Hogan FACET (Facility for Advanced Accelerator Experimental Tests) is a new facility at SLAC primarily dedicated to the study of beam-driven plasma wakefield acceleration (PWFA), an advanced particle acceleration technique which can produce longitudinal electric fields that are orders of magnitude stronger than those in conventional metal structures, and can sustain those fields over a distance of meters. These features make PWFA an attractive technology for the design of future linear colliders and light sources. The experiments at FACET will roughly mimic a single stage of a plasma-based accelerator by demonstrating the uniform acceleration of a discrete electron witness bunch, increasing its energy by about 20 GeV over a distance of 1 m in a plasma wake induced by a separate driver bunch of electrons. Another major goal of FACET is to study PWFA using various combinations of positrons and electrons in the roles of driver and witness bunch for the first time. [Preview Abstract] |
Saturday, November 12, 2011 1:48PM - 2:00PM |
F2.00005: Recent results from Super-Kamiokande on searches for neutron oscillation, Baryon Number violation, and other related studies Dylan Nicholas, Kenneth Ganezer In this talk we will review the final results on a search for neutron oscillation in Super-Kamiokande-I,~ which were very recently submitted to the high energy physics archive as arXiv:1109.4227 [hep-ex] ( at~ http://arxiv.org/abs/1109.4227) and submitted by us on behalf of the Super-Kamiokande collaboration to Physical Review Letters. These studies set new lower limits on neutron oscillation which include the major sources of systematic errors and constrain R-L symmetric theories of Grand Unification, from studies which have involved undergraduate students and physicists from CSUDH for several years. We will also discuss other recent measurements from Super-Kamiokande involving searches for Baryon number violation, neutrino astrophysics, and studies of neutrino oscillations and the student involvement in this research. This research is funded at CSUDH by grant {\#} NSF 0901048 (to CSUDH) from the NSF Particle-Astrophysics program. [Preview Abstract] |
Saturday, November 12, 2011 2:00PM - 2:12PM |
F2.00006: Searching for new light bosons with the Axion Dark Matter Experiment (ADMX) Gianpaolo Carosi The axion is a neutral pseudoscalar boson predicted to exist as a consquence of the Peccei-Quinn solution to the Strong-CP problem. Axions with masses between $\mu$eV - meV are also a natural dark matter candidate. The Axion Dark Matter Experiment (ADMX) searches for dark matter axions by looking for their resonant conversion to detectable photons via the Primakoff Effect in a microwave cavity immersed in a strong static magnetic field. Here I will discuss the operating principles of the ADMX experiment along with results from recent data runs and progress towards the next phase of the experiment currently being constructed at the University of Washington. The sensitivity of ADMX to other new light bosons such as chameleon particles and hidden-sector-photons will also be discussed. [Preview Abstract] |
Saturday, November 12, 2011 2:12PM - 2:24PM |
F2.00007: The Microstrip SQUID Amplifier: Upgrading the Axion Dark Matter Experiment (ADMX) John Clarke, Darin Kinion The axion detector, now at the University of Washington, Seattle. requires a very low noise amplifier in the 1-GHz frequency range. In the first generation detector, the cavity was cooled to 1.5 K and used a HEMT (High Electron Mobility Transistor) amplifier with a noise temperature T$_N$ of 1.7 K. Thus, the system noise temperature T$_S$ was 3.2 K. To achieve significantly lower noise temperatures, we developed the Microstrip SQUID Amplifier (MSA) in which the input coil forms a microstrip with the SQUID washer. When the length of the coil corresponds to a half-wavelength of the signal, the gain is typically 20 dB. We measured the gain and noise of an MSA at 0.62 GHz, and achieved a minimum noise temperature T$_N = 48 \pm 5$ mK for a bath temperature of 50 mK and at a frequency slightly below resonance, as predicted. The quantum limit is 30 mK. Since the time for the axion detector to scan a given frequency range scales as T$_S^2$, replacing the HEMT with a SQUID and cooling the cavity to 50 mK potentially reduces the scan time by three orders of magnitude. In a proof-of-principle run, the system was operated at 1.7 K with an MSA readout, and performed as predicted. A total of 88,370, 80-second data sets were acquired, corresponding to 82 days of data acquisition. [Preview Abstract] |
Saturday, November 12, 2011 2:24PM - 2:36PM |
F2.00008: Constraints on a Minimal Flavor Violating Sector from Electroweak Precision Data Christopher W. Murphy We examine the electroweak physics of a new physics sector that is symmetric under the Standard Model quark flavor group, $G_F = SU(3)_Q \times SU(3)_U \times SU(3)_D$. Constraints on vector boson representations of this sector are analyzed using their contributions to the self-energies of the EW gauge bosons. Vector masses close to the electroweak symmetry breaking scale are found to be consistent with precision data in almost all of the allowed representations, and in certain cases an EWSB scale mass is possible in a large region of parameter space. [Preview Abstract] |
Saturday, November 12, 2011 2:36PM - 2:48PM |
F2.00009: $\alpha $-quantized Einstein masses for leptons, quarks, hadrons, gauge bosons, and Higgs constants Malcolm Mac Gregor The Einstein particle mass $\varepsilon _{i}$ is defined by the equation $\varepsilon _{i}$ = E$_{i}$ / c$^{2}$. The basic particle ground states have unique additive Einstein masses (energies), and they interleave in $\alpha $-quantized ($\alpha ^{-1}$ = 137) energy plots to form distinctive excitation patterns. The $\varepsilon _{u,d,s,c,b,t}$ Einstein masses are \textit{constituent-quark} masses. Particle generation proceeds via ``$\alpha $-boosted'' \textit{boson}, \textit{fermion}, and \textit{gauge-boson} ``unit masses,'' which are ``bundled'' together to form particles and quarks. The Einstein mass equations extend throughout the entire range of particle masses. Lederman and Hill\footnote{L. M. Lederman and C. T. Hill, \textit{Symmetry }(Prometheus Books, Amherst, 2004), p. 282.} note that the scalar Higgs and Fermi fields are at the 175 GeV energy scale of the top quark $t$, and they suggest the Higgs coupling constant equation $g_{e}=m_{e}$/$m_{t}$ = 0.0000029, which matches the Einstein mass expression $g_{e}=\alpha ^{2}$/18. [Preview Abstract] |
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