Bulletin of the American Physical Society
APS April Meeting 2013
Volume 58, Number 4
Saturday–Tuesday, April 13–16, 2013; Denver, Colorado
Session D12: QCD |
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Chair: Nikos Varelas, University of Illinois at Chicago Room: Plaza Court 1 |
Saturday, April 13, 2013 3:30PM - 3:42PM |
D12.00001: Measurement of the differential cross sections for the production of an isolated photon with associated jet in $p\bar{p}$ collisions at $\sqrt{s} = 1.96$~TeV Alexander Verkheev The process $p\bar{p} \rightarrow \gamma + {\mathrm{jet}} + X$ is studied using 8.7~fb$^{-1}$ of data collected by the D0 detector at the Fermilab Tevatron collider at a center-of-mass energy $\sqrt{s} = 1.96$~TeV. Photons are reconstructed with rapidities $|y_{\gamma}| < 1.0$ and $1.5 < |y_{\gamma}| < 2.5$ with transverse momenta in the range $30 < p_{T \gamma} < 400$~GeV, while jets are reconstructed in four rapidity regions up to $|y_{\mathrm{jet}}| < 3.2$. The differential cross section $d^3\sigma/dP_{T \gamma} dy_{\gamma} dy_{\mathrm{jet}}$ is measured as a function of $p_{T \gamma}$ in 16 regions, differing by the relative orientations of the photon and the jet in rapidity. Results are compared with next-to-leading order calculations and to the {\sc pythia} and {\sc sherpa} Monte Carlo event generators. [Preview Abstract] |
Saturday, April 13, 2013 3:42PM - 3:54PM |
D12.00002: K$_{S}^{0}$ Production at the Main Injector Particle Production Experiment at Fermilab Amandeep Singh The Main Injector Particle Production (MIPP) experiment at Fermilab is a full acceptance spectrometer to measure hadronic particle production using beams of $\pi^{\pm}$, $\rm{K^{\pm}}$, p and $\rm{\bar{p}}$ ranging in momentum from 5 to 120 GeV/c incident on Liquid-Hydrogen, Beryllium, Carbon, Bismuth, Uranium and NuMI targets. The experiment is capable of excellent charged particle identification using Time Projection Chamber (TPC), Time of Flight (ToF), multicell Cherenkov, RICH detector and Calorimeters. A technique to reconstruct K$_{S}^{0}$ has been developed and will be described. We present the result of inclusive cross-section measurement of K$_{S}^{0}$ from the interaction of 84 GeV/c protons with Liquid-Hydrogen target and 120 GeV/c protons with Carbon, Beryllium, Bismuth and Uranium targets. [Preview Abstract] |
Saturday, April 13, 2013 3:54PM - 4:06PM |
D12.00003: Probing strongly-coupled systems through Dirac eigenmodes Anqi Cheng, Anna Hasenfratz, Gregory Petropoulos, David Schaich The eigenmodes of the Dirac operator contain a wealth of information about the dynamics of strongly-coupled systems. I will present how to extract the scale-dependent mass anomalous dimension from the renormalization group invariant mode number of the massless Dirac operator. Our method is universal and can be applied to any lattice model of interest. We investigate SU(3) lattice gauge theories with $N_f = 4$, 8 and 12 light or massless fermions. By combining simulations on multiple lattice volumes, and when possible several gauge couplings, we are able to measure the anomalous dimension across a wide range of energy scales. The 4-flavor model behaves as expected for a QCD-like system, while our 12-flavor results indicate the existence of an infrared fixed point. For the 8-flavor model we observe a large anomalous dimension across a wide range of scales. [Preview Abstract] |
Saturday, April 13, 2013 4:06PM - 4:18PM |
D12.00004: Kaon Production at the Fermilab Main Injector Emily Lindgren The kinematic behavior and production of Kaons is an important input to planning and design for future kaon experiments. The data for this study was collected by the MIPP (Main Injector Particle Production) experiment at Fermi National Accelerator Laboratory. The kaons were produced by 120 GeV energy proton beam incident on a Bismuth target. This study reports the rate of production and the kinematic distributions of particles that were identified as Kaons using particle identification techniques. [Preview Abstract] |
Saturday, April 13, 2013 4:18PM - 4:30PM |
D12.00005: Running coupling and pomeron loop effects on inclusive and diffractive DIS cross sections Maria Beatriz Gay Ducati, Emmanuel de Oliveira, Jo\~ao Thiago de Santana Amaral Within the framework of a (1$+$1)--dimensional model which mimics high energy QCD, we study the behavior of the cross sections for inclusive and diffractive deep inelastic scattering cross sections. We analyze the cases of both fixed and running coupling within the mean field approximation, in which the evolution of the scattering amplitude is described by the Balitsky-Kovchegov equation, and also through the pomeron loop equations, which include in the evolution the gluon number fluctuations. In the diffractive case, similarly to the inclusive one, the suppression of the diffusive scaling, as a consequence of the inclusion of the running of the coupling, is observed. [Preview Abstract] |
Saturday, April 13, 2013 4:30PM - 4:42PM |
D12.00006: Fragmentation functions and MHV amplitudes in light-front perturbation theory Christian A. Cruz-Santiago, Anna M. Stasto We investigate the tree level multi-gluon component of the fragmentation functions within the framework of light-front perturbation theory. Recursion relations are found for the fragmentation functions. We see that these are the light-front analogs of the Berends-Giele recursion relations. We also demonstrate how to obtain scattering amplitudes from the fragmentation functions. Using a special helicity configuration along with the recursion relation we find the first few lowest order maximally-helicity violating amplitudes. For this choice of helicities we then solve the recursion explicitly and observe that the solution carries the same structure as the maximally-helicity violating amplitudes. [Preview Abstract] |
Saturday, April 13, 2013 4:42PM - 4:54PM |
D12.00007: Double Parton Interactions in $\gamma + b/c + 2$~jet events in $p\bar{p}$ collisions at $\sqrt{s} = 1.96$~TeV Georgy Golovanov We use a sample of $\gamma$ + heavy flavor jet + dijet events collected by the D0 detector in a data sample corresponding to an integrated luminosity of about 8.7 fb$^{-1}$ of $p\bar{p}$ collisions at the Fermilab Tevatron collider, to study properties of events with double parton scattering (DPS) in single $p\bar{p}$ collisions at $\sqrt{s} = 1.96$ TeV. We describe the measurement of the DPS event fraction and the effective cross section ($\sigma_{\mathrm{eff}}$) for double parton scattering. [Preview Abstract] |
Saturday, April 13, 2013 4:54PM - 5:06PM |
D12.00008: Particle Production Measurements using the MIPP Detector at Fermilab Sonam Mahajan The Main Injector Particle Production (MIPP) experiment at Fermilab is a fixed target hadron production experiment which uses 120 GeV/c primary protons from the Main Injector to produce secondary beams of $\pi^{\pm}, \rm{K}^{\pm}$, p and $\bar{\rm{p}}$ from 5 to 90 GeV/c as projectiles on nuclear targets. It is designed to measure particle production in interactions of projectile p/$\bar{\rm{p}}/\pi^{\pm}/\rm{K}^{\pm}$ on nuclear targets which include H, Be, C, Bi and U, and a dedicated run with the NuMI target. We present the inelastic cross sections for 58 and 85 GeV/c p-H interactions, and 58 and 120 GeV/c p-C interactions. A new method is described to account for the low multiplicity inefficiencies in the interaction trigger using KNO scaling. Inelastic cross sections as a function of multiplicity are also presented. The MIPP data are compared with the Monte Carlo predictions and previous measurements. We also describe an algorithm to identify charged particles ($\pi^{\pm}/\rm{p}/\bar{\rm{p}}$ etc.), and present preliminary e$^{\pm}, \pi^{\pm}, \rm{K}^{\pm}$, p and $\bar{\rm{p}}$ particle production cross sections in bins of p$_{\rm{T}}^{2}$ and x$_{\rm{F}}$. [Preview Abstract] |
Saturday, April 13, 2013 5:06PM - 5:18PM |
D12.00009: Improved Lattice Renormalization Group Techniques Gregory Petropoulos, Anqi Cheng, Anna Hasenfratz, David Schaich Finding the renormalization group (RG) properties of quantum field theories is useful to understand conformal and nearly conformal quantum field theories. Monte Carlo Renormalization Group (MCRG) methods are an effective way of determining the bare step scaling function non perturbatively. In this talk I present an improvement to traditional MCRG that makes more robust predictions. Our method finds the beta function by using wilson flow to approach the renormalized trajectory determined by a unique RG transformation. By optimizing the extent of the wilson flow for different couplings we can find a unique beta function. We applied our renormalization group techniques to SU(3) gauge theories with 8 and 12 flavors in the chiral limit and found an infrared fixed point in the 12 flavor case. [Preview Abstract] |
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