Bulletin of the American Physical Society
2009 APS April Meeting
Volume 54, Number 4
Saturday–Tuesday, May 2–5, 2009; Denver, Colorado
Session L9: QCD Topics |
Hide Abstracts |
Sponsoring Units: DPF Chair: Boris Kayser, Fermilab Room: Governor's Square 11 |
Sunday, May 3, 2009 3:30PM - 3:42PM |
L9.00001: The GlueX Experiment at Jefferson Lab Seema Dhamija One of the main scientific questions that remains unanswered in subatomic physics is the nature and behaviour of the ``glue'' which holds the quarks together. The puzzling feature of this quark-gluon interaction is that quarks are never found free, a phenomenon known as confinement. Since gluons carry colour charge, they cause the formation of chromoelectric flux tubes, which may yield unusual objects such as glueballs or hybrids. In certain models the latter can be produced with quantum numbers not allowed in the simple quark model providing a powerful signature for hybrid meson spectroscopy. The GlueX experiment will provide for the detailed spectroscopy necessary to map out the hybrid meson spectrum, which is essential for an understanding of the confinement mechanism and the nature of the gluon in QCD. It will be housed in the new experimental hall (Hall D) which will be constructed as part of the 12 GeV upgrade. The physics motivating the search and the status of the experiment will be reviewed. [Preview Abstract] |
Sunday, May 3, 2009 3:42PM - 3:54PM |
L9.00002: Initial state gluon radiation studies in Drell-Yan events at the LHC Kyoko Yamanaka In the measurement of properties of the top quark and other heavy particles that are produced in proton-proton collisions at the LHC, it is important to account for the effect of initial state gluon radiation (ISR). In order to study ISR at the LHC, we will use a method that has been pioneered by CDF using Drell-Yan events to understand the effect of ISR in top-pair production at the Tevatron. The Drell-Yan process is well suited for ISR studies as it does not suffer from additional final state radiation contributions. We lay out a method in which we determine systematic uncertainties due to ISR by comparing Monte Carlo simulated events to initial data from the ATLAS experiment expected to be taken later this year. [Preview Abstract] |
Sunday, May 3, 2009 3:54PM - 4:06PM |
L9.00003: Measurement of the Dijet Mass Spectrum at $\sqrt{s}$=1.96 TeV in the D0 experiment Mandy Rominsky We present the differential dijet mass cross section measurement at a center of mass energy of 1.96 TeV in six rapidity regions using the D0 detector. This measurement utilizes 0.7 fb$^{-1}$ of integrated luminosity collected in proton-antiproton collisions during Run IIa of the Fermilab Tevatron. We correct the data back to particle level and compare it to parton-level theory to which fragmentation and underlying event corrections have been added. [Preview Abstract] |
Sunday, May 3, 2009 4:06PM - 4:18PM |
L9.00004: The Search for Exotic Mesons in the 3$\pi$ System in Photoproduction with CLAS Craig Bookwalter In addition to ordinary $q\bar{q}$ pairs, quantum chromodynamics (QCD) permits many other possibilities in meson spectra, such as gluonic hybrids, glueballs, and tetraquarks. Experimental discovery and study of these exotic states provides insight on the nonperturbative regime of QCD. Over the past twenty years, some searches for exotic mesons have met with controversial results, especially those obtained in the three-pion system. Prior theoretical work indicates that in photoproduction one should find gluonic hybrids at significantly enhanced levels compared to that found in pion production. To that end, the CLAS g12 run was recently completed at Jefferson Lab, using a liquid hydrogen target and tagged photons from a 5.71 GeV electron beam. The CLAS experimental apparatus was modified to maximize forward acceptance for peripheral production of mesons. The resulting data contains the world's largest 3$\pi$ photoproduction dataset, with 3$\pi$ events numbering in the millions. Early results describing the data quality, kinematics, and dynamics will be shown. [Preview Abstract] |
Sunday, May 3, 2009 4:18PM - 4:30PM |
L9.00005: Towards 4-quark states with 2 heavy quarks R.R. Silbar, T. Goldman We study the changes in the relativistic wave functions of quarks in a (linear) confining potential as a function of quark mass and the effect of color Coulomb contributions. Our goal is to delineate the uncertainties in phenomenological estimates of the masses of multiquark (molecular) states that are expected in QCD. [Preview Abstract] |
Sunday, May 3, 2009 4:30PM - 4:42PM |
L9.00006: Jet identification and energy scale corrections in a high-luminosity environment at the LHC David Miller The LHC physics program will ultimately probe not only the highest energies ever produced in the laboratory but also the most numerous and frequent collisions between hadronic particles ever. These luminosities will produce hadronic jets from simultaneous proton-proton collisions in unprecedented numbers, presenting extreme challenges for jet identification, calibration and missing energy ($E_{T}$) measurements. We present a unified jet energy scale program designed to account for these uncorrelated soft interactions using the advanced technique of associating calorimeter jets to reconstructed primary vertices using tracks. This approach suppresses the background contributions from these ``pile-up'' interactions and allows for jet-by-jet energy scale corrections for multiple interactions. This approach is shown to be vital for coping with the unparalleled luminosity of the LHC. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700