Bulletin of the American Physical Society
2019 Fall Meeting of the APS Division of Nuclear Physics
Volume 64, Number 12
Monday–Thursday, October 14–17, 2019; Crystal City, Virginia
Session SF: Current and Future Jet Measurements |
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Chair: Ron Soltz, Lawrence Livermore National Laboratory Room: Salon 6 |
Thursday, October 17, 2019 10:30AM - 10:42AM |
SF.00001: ABSTRACT WITHDRAWN |
Thursday, October 17, 2019 10:42AM - 10:54AM |
SF.00002: Testing and Characterization of the Scintillator Tiles for the sPHENIX Hadronic Calorimeter Uttam Acharya sPHENIX is a new experiment at RHIC that is designed to quantify the properties of quark-gluon plasma created in relativistic heavy ions collisions with measurements of jets and quarkonia. A crucial component of the sPHENIX detector design for jet measurements is the hadronic calorimeter (HCal) which is located outside of the magnet and composed of plastic scintillating tiles sandwiched between tapered, steel plates, and read out with wavelength shifting fibers and Silicon Photomultipliers (SiPM). The HCal includes 7,680 scintillating tiles that are currently being produced at Uniplast plant in Russia. A test station has been built at Georgia State University to test the quality and performance of each of these tiles with cosmic rays. The results of this test will also be used to optimize the performance of the device towers that will be constructed from these tiles by grouping the tiles with similar performance in each tower. This talk is focused on the design of the test station and the current result of the performance characterization studies of the sPHENIX HCal tiles. [Preview Abstract] |
Thursday, October 17, 2019 10:54AM - 11:06AM |
SF.00003: Validation of Production SiPMs for the sPHENIX Experiment Nathan Grau The sPHENIX detector is designed to measure calorimetric jets and heavy flavors to study the microscopic properties of the quark-gluon plasma produced in ultrarelativistic heavy ion collisions at RHIC. The electromagnetic and hadronic calorimeters will cover full azimuth and |$\eta$|<1. The calorimeters are readout through common electronics and use silicon photomultipliers (SiPMs) as the optical sensor. The full detector requires 106,000 SiPMs, with the Hamamatsu S12572-015P having been chosen as the device to instrument the full detector. The production of this large order is ongoing and monthly shipments of 8,500 SiPMs began arriving at the University of Michigan in March of 2019. In this talk we outline the test stand developed at the University of Debrecen, the strategy to validate the SiPMs received, and the results of that evaluation. [Preview Abstract] |
Thursday, October 17, 2019 11:06AM - 11:18AM |
SF.00004: Measurement of D0 production in jets in heavy-ion collisions at the LHC with ALICE Antonio Carlos Oliveira da Silva Charm quarks are considered ideal probes of the Quark-Gluon Plasma (QGP). Due to their large mass they are produced in the early stages of ultra-relativistic heavy-ion collisions in hard-scattering processes. D$^{0}$-tagged jets are valuable tools to investigate the charm interaction with the QGP. Furthermore, charmed jets can provide information to study the mass-dependent energy loss by analysing the modification of their yield in Pb-Pb collisions with respect to pp collisions as a function of the jet transverse momentum. D$^{0}$ mesons are reconstructed through their hadronic decay channels. The large combinatorial background is rejected by applying topological selections exploiting the relatively large lifetime of D$^{0}$ mesons and the particle-identification capabilities of the detector. The signal is extracted using an invariant mass analysis. Charged-track jets are reconstructed with anti-k$_{t}$ algorithm. The ALICE detectors allow us to measure D$^{0}$-tagged jets down to low p$_{\mathrm{T}}$, where the probes are more sensitive to the effects of the hot medium. This contribution will present the current analysis status and results of the measurement of D$^{0}$-tagged jets in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV. [Preview Abstract] |
Thursday, October 17, 2019 11:18AM - 11:30AM |
SF.00005: Recent Jet Results From ALICE Patrick Steffanic The ALICE experiment at the Large Hadron Collider at CERN is optimized to study the properties of the hot, dense matter created in high energy nuclear collisions in order to improve our understanding of the properties of nuclear matter under extreme conditions. Measurements from pp and p--Pb collisions provide a baseline for measurements in heavy ion collisions. Measurements from Pb--Pb collisions indicate that the matter created in collisions at the LHC is hotter and larger than that at lower energies and behaves like a strongly interacting, nearly perfect liquid. Showers of particles--jets--resulting from hard interactions early on in the collision probe the full evolution of nuclear medium. Recent measurements of charged jet spectra, jet transverse momentum distributions and jet substructure measurements from ALICE will be presented. [Preview Abstract] |
Thursday, October 17, 2019 11:30AM - 11:42AM |
SF.00006: Jet vn in Heavy Ion Collisions at ALICE William Witt The extreme temperature and density produced in a heavy ion collision leads to the formation of a phase of matter called the quark gluon plasma (QGP). When a parton within one of the colliding nuclei scatters off a parton in the other nucleus, it results in collimated sprays of particles known as jets. These jets can be identified from clusters of final state particles observed by ALICE (A Large Ion Collider Experiment) at the LHC (Large Hadron Collider). Due to the non-uniformity of the initial QGP state, these jets exhibit angular asymmetry, quantified by jet vn. Measuring jet vn reveals information about the energy loss of partons traveling through the QGP. Results from Pb-Pb collisions at 2.76 TeV and the status of measurements in Pb-Pb colisions at 5.02 TeV will be presented. [Preview Abstract] |
Thursday, October 17, 2019 11:42AM - 11:54AM |
SF.00007: Two-particle correlation distributions on transverse momentum in relativistic heavy-ion collisions Robert Ray Two-particle correlation projections onto two-dimensional transverse momentum coordinates allow access to relativistic heavy-ion collision dynamics beyond that accessible in previous, complementary studies of two-particle angular correlations. We report charged-particle correlations from minimum-bias Au+Au collisions at $\sqrt{s_{NN}}$=200 GeV taken by the STAR experiment at RHIC. These new correlations are constructed using all charged particles within the STAR acceptance. Correlations are presented for like-sign and unlike-sign charge-pair combinations and for specific azimuthal angle projections. The major correlation features include a saddle shape and a peak extending from $p_t$ = 0.5 to 4.0 GeV/$c$. The measurements are compared to HIJING and EPOS predictions. The features of the correlations are also described by a blast-wave model and a two-component fragmentation model, representing two distinct frameworks for understanding relativistic heavy-ion collisions [Ray and Jentsch, Phys. Rev. C {\bf 99}, 024911 (2019)]. Implications of these new measurements and analysis with respect to equilibration, the origin of transverse-momentum fluctuations, longitudinal and transverse parton fragmentation, and interactions within the dense, partonic medium are discussed. [Preview Abstract] |
Thursday, October 17, 2019 11:54AM - 12:06PM |
SF.00008: Quality Assurance of the 2012 Endcap π 0 data at STAR and Analyzing 2013 Data Joseph Snaidauf The Solenoidal Tracker at RHIC (STAR) experiment based at Brookhaven National Laboratory uses collisions of polarized protons to study, among other things, the contributions of gluons to the spin of the proton. The STAR detector's Endcap Electromagnetic Calorimeter (EEMC), located in the pseudorapidity range 1 < η < 2, provides sensitivity to gluons carrying a low fraction of the proton momentum (x ~< 0.05), where the gluon spin contribution is still relatively poorly constrained. The gluon spin contribution can be determined by studying the π 0 production from p+p collisions with different orientations of the spins of the colliding protons. π 0 ’s are reconstructed using the energies deposited in the EEMC by the two decay photons and the opening angle between them. To ensure that the data from 2012 longitudinally polarized p+p collisions at √s=510 GeV under study are of useable quality, a C++ script was written to plot, as a function of run number, several key characteristics of the neutral pion reconstruction process obtained from ROOT trees. In addition, π 0 ’s were reconstructed via ROOT from the 2013 longitudinally polarized p+p collisions at √s =510 GeV. The results of these studies will be presented. [Preview Abstract] |
Thursday, October 17, 2019 12:06PM - 12:18PM |
SF.00009: (CEU) Calculating Corrections to Transverse Energy in Relativistic Heavy Ion Collisions Benjamin Smith, Tanner Mengel, Biswas Sharma, Nathan Webb, Soren Sorensen, Christine Nattrass By colliding heavy nuclei at relativistic velocities, the resulting increase in temperature and density of the collision volume can cause a phase transition of the nuclear matter to what is called a quark-gluon plasma. Several experiments to observe the behavior of this phase occur at the Relativistic Heavy Ion Collider (RHIC) in New York. As an effect of the collision, many particles are ejected transverse to the beam axis. Using published single particle spectra, the total transverse energy is calculated and can provide an independent cross check of transverse energy measurements. These calculations are using estimates for particles unable to be measured. Included in this calculation are corrections such as feeddown. I will describe several of the assumptions made and several tests of these assumptions from Monte Carlo models. [Preview Abstract] |
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