Bulletin of the American Physical Society
2012 Annual Meeting of the California-Nevada Section of the APS
Volume 57, Number 13
Friday–Saturday, November 2–3, 2012; San Luis Obispo, California
Session C3: High Energy and Accelerator Physics |
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Chair: Nan Phinney, SLAC National Accelerator Laboratory Room: Business 003 0209 |
Friday, November 2, 2012 2:00PM - 2:12PM |
C3.00001: 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 boson 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. Also, 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] |
Friday, November 2, 2012 2:12PM - 2:24PM |
C3.00002: Improved cross section calculations in ATLAS simulation packages, APPLgrid and NLOjet 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 discoveries, in addition to the promising observation of a new particle with Higgs-like properties, include supersymmetry (SUSY), extra spatial dimensions, and a whole zoo of exotic particles. Looking for these new possibilities can be extremely CPU-intensive and time consuming and therefore it is essential for the data analysis and simulations to be done as efficiently as possible. In order to analyze the data one would like to vary the different parameters such as the Parton Distribution Functions (PDF's). However, currently, the most common tools for calculating cross sections are Monte Carlo event generators such as Pythia which make data analysis very time consuming due to the fact that the entire calculation has to be repeated for every time the parameters are varied. 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 cross section calculations done at ATLAS. The APPLgrid software package allows for quick calculations with any PDF in than a second whereas the same calculation could take Pythia a few hours. The results that will be shown in here are sample calculations done by NLOjet and APPLgrid in comparison with Pythia for QCD and a Contact Interaction Model. This research project was done by the author at CERN and DESY during the summers of 2011 and 2012 and the progress has been presented thrice to the ATLAS jet Cross Section Group. [Preview Abstract] |
Friday, November 2, 2012 2:24PM - 2:36PM |
C3.00003: Experimental Analysis of Gaseous Chambers for the ATLAS Muon sub-detector Upgrade R{\&}D Emmanuel Angulo 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 during the summers of 2011 and 2012, including functional uniformity results of a new ``T-series'' chamber design developed by the ATLAS Muon detector upgrade R{\&}D team. As a result, a new visual mapping design was developed by the author that enabled an easier way to find anomalies in the chambers. This work has been presented to ATLAS Weekly Micromegas Meeting's 6 times during the summers of 2011 and 2012. [Preview Abstract] |
Friday, November 2, 2012 2:36PM - 2:48PM |
C3.00004: Simulating the Response of the High-Intensity Luminosity Monitor at the LHC Samuel Hedges, Howard Matis, Alessandro Ratti, Massimo Placidi, William Turner To achieve the recent discovery of a Higgs-like object at the LHC, the machine operators needed detectors to optimize the number of collisions in the machine. One of these detectors is called the Beam Rate of Neutrals (BRAN). The BRAN is a gas ionization chamber detector developed at LBNL and used to measure relative luminosity of collisions on both sides of the ATLAS and CMS interaction regions. We have used the Monte Carlo simulation software FLUKA to simulate the detector's response to p-p, p-Pb, and Pb-Pb collisions at both current and future colliding conditions. In this talk, we will describe the detector and the results from the simulations. The simulations can be used to explain differences between the energy deposited in the BRAN at ATLAS and CMS. We will compare these measurements to data taken with the detector. [Preview Abstract] |
Friday, November 2, 2012 2:48PM - 3:00PM |
C3.00005: Solar Neutrino Measurements in Super-Kamiokande-IV Andrew Renshaw Super-Kamiokande-IV begin data taking in September of 2008, and with upgraded electronics and many improvements to water system dynamics, calibration, and analysis techniques the solar neutrino energy threshold was pushed down to 3.5MeV (recoil electron kinetic energy). The observed recoil electron spectrum flavors a flat suppression over distortions predicted by standard neutrino flavour oscillation parameters by 1.1 to 1.9$\sigma$. Using a maximum likelihood fit of the amplitude of the expected zenith variation, the observed day/night asymmetry of -2.8$\pm$1.1(stat)$\pm$0.5(syst)\% is consistent with zero at the 2.3$\sigma$ level. This significance is increase to 2.9$\sigma$ when combined with SNO's day/night measurement, giving a slight hint for the regeneration of electron type solar neutrinos as they travel through Earth's matter. [Preview Abstract] |
Friday, November 2, 2012 3:00PM - 3:12PM |
C3.00006: Recent results from Super-Kamiokande on searches for baryon number violation and on neutrino oscillations, neutrino astrophysics and plans for the future of Super-Kamiokande including Hyper-K Dylan Nicholas In this talk we will describe results obtained during the last two years at Super-Kamiokande on searches for Baryon Number violation including nucleon decay and neutron oscillations as well as studies of neutrino oscillations including the mixing parameters and neutrino astrophysics. We will also briefly discuss future plans for Super-Kamiokande including Hyper-K. [Preview Abstract] |
Friday, November 2, 2012 3:12PM - 3:24PM |
C3.00007: The planned search for free neutron-antineutron transformation using the nnbarX experiment at Fermilab and how it relates to bound neutron oscillations at Super-Kamiokande and elsewhere Eddie Banuelos In this presentation we will describe the role of CSUDH and present initial planning results on a new experiment at Fermilab called nnbarX that will use neutrons from a 1 MW cold spallation source near the Fermilab main accelerator ring which is being upgraded. This project will eventually probe theories of grand unification of the fundamental forces, the stability of matter, and how Baryons were created in the early stages of the big bang, at levels of sensitivity to the baryon lifetime that will be 100-10000 higher than what is currently available and will rule out or confirm leading theories of grand unification in which neutrons and other fermions are equally mixed with their antiparticles and can transform to each other in Right-Left symmetric theories such as SO(10). We at CSUDH will be directly collaborating with the University of Tennessee Knoxville, University of Indiana Bloomington, North Carolina State University, Femilab and Los Alamos National Laboratory on detector R \& D for nnbarX and will be also working with a few other institutions in the US and in other countries. [Preview Abstract] |
Friday, November 2, 2012 3:24PM - 3:36PM |
C3.00008: The Heavy Photon Search Experiment: Searching for Dark Photons at Jefferson Lab Omar Moreno The Heavy Photon Search (HPS) is new experiment at Jefferson Lab (JLab), which will search for massive vector gauge bosons (heavy/dark photons) in the mass range of 20-1000 MeV/c$^2$. These dark photons are expected on very general theoretical grounds and are motivated by recent astrophysical evidence suggesting they may mediate dark matter annihilations and/or interactions with ordinary matter. The dark photon couples to the ordinary photon through kinetic mixing which induces their weak coupling to electrons. This allows for dark photon production through a process analogous to bremsstrahlung radiation. If the coupling is large enough, the subsequent decay to $e^+e^-$ will produce a narrow peak in the $e^+e^-$ mass spectrum which can be observed above the dominant QED trident background. If the coupling is small enough, then the dark photons will travel detectable distances before decaying, providing a second signature. Using JLab's high luminosity electron beam along with a compact large acceptance forward spectrometer, silicon vertex tracker, PbWO$_4$ electromagnetic calorimeter and a muon detector, HPS will explore a large domain in the mass/coupling plane with extraordinary sensitivity. In this talk, I will discuss the status of the HPS experiment. [Preview Abstract] |
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