Bulletin of the American Physical Society
3rd Joint Meeting of the APS Division of Nuclear Physics and the Physical Society of Japan
Volume 54, Number 10
Tuesday–Saturday, October 13–17, 2009; Waikoloa, Hawaii
Session CB: Mini-Symposium on Heavy Flavor and Hard Probes in the Quark Gluon Plasma II |
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Chair: Takao Sakaguchi, Brookhaven National Laboratory Room: Kona 4 |
Thursday, October 15, 2009 9:00AM - 9:30AM |
CB.00001: Latest Results from Heavy Flavor Measurements Invited Speaker: Heavy flavors are ideal probes to quantify the QCD medium properties in relativistic heavy ion collisions. In this talk, I will review the most recent measurements and results on open heavy flavor and heavy quarkonium production from heavy ion experiments. I will discuss our current understandings of heavy flavor hadron production mechanisms, heavy quark in-medium interactions, QCD medium properties we've learned so far, as well as the limitations of these measurements. In the end, I will outlook a bright future in heavy flavor measurements with machine and detector upgrades in the RHIC II era. [Preview Abstract] |
Thursday, October 15, 2009 9:30AM - 9:45AM |
CB.00002: Measurement of charm and bottom production at RHIC-PHENIX Yuhei Morino Measurements of heavy flavor production (charm and bottom) in $p+p$ collisions provides stringent tests for perturbative QCD~(pQCD) calculations. In addition, heavy quarks are good probes of the hot and dense medium created in relativistic heavy ion collisions, since they are mainly generated at the beginning of collisions and interact with the media in all collision stages. Production of heavy quarks has been studied by the PHENIX experiment at RHIC via measurements of single leptons from semi-leptonic decays in $p+p$ and Au+Au collisions at $\sqrt{s_{NN}} =200$~GeV. The ratio of $(b\rightarrow e)$ to $(c\rightarrow e+ b\rightarrow e)$ is extracted from the correlation between the heavy flavor electrons and associated hadrons. The ratio, $(b\rightarrow e)/(c\rightarrow e+ b\rightarrow e)$, is important to interpret the results of heavy flavor in Au+Au collisions. In this presentation we will show the latest PHENIX results for the production of charm and bottom. In addition, large energy loss and flow of the heavy quarks will be discussed based on the measured $(b\rightarrow e)/(c\rightarrow e+ b\rightarrow e)$. [Preview Abstract] |
Thursday, October 15, 2009 9:45AM - 10:00AM |
CB.00003: High Order Opacity Analysis of Jet Quenching Miklos Gyulassy, Alessandro Buzzatti, Andrej Ficnar, Simon Wicks Recent progress in implementing the DGLV multiple collision opacity series using Monte Carlo techniques is presented to compute triple differential jet energy loss and transverse acoplanarity for both light and heavy quark jets. Predictions for RHIC and LHC di-hadron as well as dijet and jet-hadron correlations will be presented. [Preview Abstract] |
Thursday, October 15, 2009 10:00AM - 10:15AM |
CB.00004: Langevin + Hydrodynamics Approach to Heavy Quark Diffusion in the Quark Gluon Fluid Yukinao Akamatsu, Tetsuo Hatsuda, Tetsufumi Hirano Relativistic Langevin dynamics is developed under the background of hydrodynamic expansion of strongly interacting quark-gluon fluid. The drag force acting on charm and bottom quarks is parametrized according to the formula calculated by AdS/CFT correspondence. In this setup, we calculate the nuclear modification factor $R_ {AA}$ for the single electrons from the charm and bottom quarks to extract the magnitude of the drag force from the PHENIX and STAR data. The $R_{AA}$ for electrons with high transverse momentum indicates that the drag force is much stronger than the leading order perturbative QCD prediction and is rather close to the AdS/CFT prediction. Effects of the drag force to the elliptic flow $v_2$ of single electrons will be also discussed. This approach is further applied to the study of heavy quark correlation. We will report our recent prediction of the electron-muon and electron-hadron correlations, which are closely related to the dynamical properties of heavy quark in the hot medium. [Preview Abstract] |
Thursday, October 15, 2009 10:15AM - 10:30AM |
CB.00005: ABSTRACT WITHDRAWN |
Thursday, October 15, 2009 10:30AM - 10:45AM |
CB.00006: From the discovery of direct-single-$e^{\pm}$ from charm in 1974 to a fundamental test of the Higgs Yukawa coupling in Heavy Ion Collisions Michael Tannenbaum Searches for the intermediate boson, $W^{\pm}$, the heavy quantum of the Weak Interaction, via its semi-leptonic decay, $W\rightarrow e +\nu$, in the 1970's instead discovered unexpectedly large hadron production at high $p_T$, notably $\pi^0$, which provided a huge background of $e^{\pm}$ from internal and external conversions. Methods developed at the CERN ISR led to the discovery of direct-single-$e^{\pm}$ in 1974, later determined to be from the semi-leptonic decay of charm which had not yet been discovered. The same methods---i) $\geq 10^5$ charged hadron rejection; ii) minimum of material in the aperture to avoid external conversions; iii) zero magnetic field on the axis to avoid de-correlating conversion pairs; v) precision background determination in the direct-single-$e^{\pm}$ signal channel by adding external converter---were used at RHIC to make precision measurements of heavy quark production in p-p and Au+Au collisions, leading to the puzzle of apparent equal suppression of light and heavy quarks in the QGP. If the Higgs mechanism gives mass to gauge bosons but not to fermions, then a proposal that all 6 quarks are nearly massless in a QGP, which would resolve the puzzle, can not be excluded. This proposal can be tested with future measurements. [Preview Abstract] |
Thursday, October 15, 2009 10:45AM - 11:00AM |
CB.00007: Electron-Muon Correlations in p+p and d+Au at RHIC-PHENIX at $\sqrt{s} = 200$ GeV Tatia Engelmore Heavy quarks are useful in understanding the hot, dense medium created in a heavy ion collision, and are an important test of proposed mechanisms of energy loss. In order to study heavy quark production, electron-muon pairs are a valuable measurement because these are produced with a clean signal. PHENIX detects electrons in the central arms and muons in the forward and backward regions, so it is sensitive to heavy quark pairs produced in an intermediate rapidity range. To understand the behavior of $e-\mu$ pairs in the medium, we first need to establish a baseline measurement in $p$+$p$, as well as determine the cold-matter effects in $d$+$Au$ collisions. In $d$+$Au$, a comparison of the yield of pairs with muons at forward rapidity (small x) to pairs with muons at backward rapidity (large x) could help to better understand saturation and shadowing effects on heavy quarks versus enhancement from antishadowing. Results of $e-\mu$ azimuthal correlations in $p$+$p$ will be presented and related to heavy quark jet properties. Also, recent work on $e-\mu$ in $d$+$Au$ collisions will be discussed. [Preview Abstract] |
Thursday, October 15, 2009 11:00AM - 11:15AM |
CB.00008: Characterizing cold nuclear matter effects through dielectrons in d+Au collisions at PHENIX Jason Kamin Electron-positron pairs are effective probes for investigating the hot, dense matter created in RHIC collisions because they are color neutral and, once created, do not interact strongly with the medium. As a result, they retain characteristics of the full time evolution and dynamics of the system. Among the many features, the low mass region (m$<$1 GeV/c$^2$) consists primarily of pairs from Dalitz decays of light hadrons and direct decays of vector mesons that can be modified by the medium, while the intermediate (1$<$m$<$3 GeV/c$^2$) and high (4$<$m$<$12 GeV/c$^2$) mass regions are dominated by charm and bottom. The PHENIX experiment has presented the dielectron continuum in p+p, Cu+Cu and Au+Au collisions at $\sqrt{s_{NN}} = 200$~GeV. Recently PHENIX measured d+Au collisions which are crucial as they provide a complimentary reference for comparision with heavy ion collisions while illuminating cold nuclear matter effects. The statistics provided by the 2008 RHIC d+Au data set allow the dielectron spectrum to extend to mass ranges where bottom dominates. These data are currently being analyzed and the dielectron status will be presented. [Preview Abstract] |
Thursday, October 15, 2009 11:15AM - 11:30AM |
CB.00009: Hadroproduction of Charmonium Excited States and Bottomonium at $\sqrt{s_{NN}}=200 GeV$ Measured by PHENIX Detector Cesar L. Silva During the last few years RHIC has demonstrated sizable medium effects on the inclusive $J/\psi$ yields in heavy ion collisions. Feed-down contributions, mainly from excited charmonium states $\chi_C$ and $\psi^{\prime}$, should be considered when comparing the measured production and medium modification factors with theoretical models. Relative production between different charmonium states can also provide insights about the production mechanisms, different hadronic absorption or breakup cross sections and sequential charmonium dissociation in sQGP. Bottomonium measurements can probe the same physics involved in charmonium, but with more reliable theoretical production calculations, no important coalescence at RHIC energies and a presumed higher dissociation temperature. In this presentation we will show recent measurements of $\chi_c$, $\psi^{\prime}$ in $p$+$p$ collisions, $\Upsilon$(1S,2S,3S) in $p$+$p$ and Au+Au collisions, the progress towards these similar measurements in $d$+Au collisions as well as expected advances using upcoming detector upgrades in PHENIX. [Preview Abstract] |
Thursday, October 15, 2009 11:30AM - 11:45AM |
CB.00010: $\Upsilon $production in p+p, d+Au, Au+Au collisions at $\sqrt {S_{NN} } =$200 GeV in STAR Rosi Reed, Manuel Calderon, Debasish Das, Pibero Kisa, Haidong Liu The properties of the dense matter produced in heavy-ion collisions can be investigated by studying its effect on quarkonia production. In particular, the $\Upsilon $states are of interest because both the effect due to co-movers and feed down is smaller than for J/$\psi $. Suppression of quarkonia is theorized to be a QGP signature due to the Debye color screening of the potential between the heavy quarks. Lattice studies show that a sequential suppression of quarkonia states in heavy ion collisions when compared to production in p+p collisions can provide us with a thermometer for the matter produced in relativistic heavy-ion collisions. This requires a detailed understanding of $\Upsilon $production in p+p collisions, as well as d+Au calculations so that R$_{AA}$ can determined. We will present our preliminary results for mid-rapidty $\Upsilon $production in p+p, d+Au, and Au+Au at $\sqrt {S_{NN} } =$200 GeV in the STAR experiment. We will compare these results with theoretical QCD calculations. [Preview Abstract] |
Thursday, October 15, 2009 11:45AM - 12:00PM |
CB.00011: Future measurement of Charm and Beauty Using the Silicon Vertex Detector at PHENIX Xiaorong Wang The study of heavy quarks (c and b) is essential to adequately understand in-medium energy loss and to test the basics properties of QCD. The current PHENIX heavy flavor physics program will be significantly enhanced by addition of the Silicon Vertex Detector (VTX) and Forward Silicon Vertex upgrade detector (FVTX) in a much broader acceptance then existing PHENIX detectors. These silicon trackers are planned to be put into operation in FY2011. They will provide precision tracking, reconstruction of the primary vertex and the recognition of secondary decay vertices in the collisions. This capability will enhance the heavy-quark signal and greatly reduce backgrounds. The description of tracking performance and some of the physics goals and capabilities from the simulations will be presented. [Preview Abstract] |
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