Fri·Mar 18, 2016Friday·March 18, 2016

1. 01*

   Near-side azimuthal and pseudorapidity correlations using neutral strange baryons and mesons in d+Au, Cu+Cu and Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV

   STAR Collaboration: B. Abelev🇺🇸 · L. Adamczyk🇵🇱 · J. K. Adkins🇺🇸 · G. Agakishiev🇷🇺 · M. M. Aggarwal🇮🇳 · Z. Ahammed🇮🇳 · I. Alekseev🇷🇺 · A. Aparin🇷🇺 · D. Arkhipkin🇺🇸 · E. C. Aschenauer🇺🇸 · A. Attri🇮🇳 · G. S. Averichev🇷🇺 and 331 other authors

   We present measurements of the near-side of triggered di-hadron correlations using neutral strange baryons ($\Lambda$, $\bar{\Lambda }$) and mesons ($K_S^0$) at intermediate transverse momentum (3 $<$ $p_T$ $<$ 6 GeV/$c$) to look for possible flavor and baryon/meson dependence. This study is performed in $d$+Au, Cu+Cu and Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV measured by the STAR experiment at RHIC. The near-side di-hadron correlation contains two structures, a peak which is narrow in azimuth and pseudorapidity consistent with correlations due to jet fragmentation, and a correlation in azimuth which is broad in pseudorapidity. The particle composition of the jet-like correlation is determined using identified associated particles. The dependence of the conditional yield of the jet-like correlation on the trigger particle momentum, associated particle momentum, and centrality for correlations with unidentified trigger particles are presented. The neutral strange particle composition in jet-like correlations with unidentified charged particle triggers is not well described by PYTHIA. However, the yield of unidentified particles in jet-like correlations with neutral strange particle triggers is described reasonably well by the same model.

   nucl-exPRC(2016)·12 citations
2. 02*

   Universal relations between nongaussian fluctuations in heavy-ion collisions

   Jiunn-Wei Chen🇹🇼 · Jian Deng🇨🇳 · Hiroaki Kohyama🇹🇼 · Lance Labun🇺🇸

   We show that universality near a critical end point implies a characteristic relation between third- and fourth-order baryon susceptibilities ${\chi }_3$ and ${\chi }_4$, resulting in a banana-shaped loop when ${\chi }_4$ is plotted as a function of ${\chi }_3$ along a freeze-out line. Including the individual enhancements of ${\chi }_3$ and ${\chi }_4$ near a critical point, these features may be a consistent set of observations supporting the interpretation of baryon fluctuations data as arising from criticality.

   ↳ hep-phnucl-exnucl-thPRD(2017)·16 citations
3. 03*

   On the role of secondary pions in spallation targets

   Davide Mancusi🇫🇷 · Sergio Lo Meo🇮🇹 · Nicola Colonna🇮🇹 · Alain Boudard🇫🇷 · Miguel Antonio Cortés-Giraldo🇪🇸 · Joseph Cugnon🇧🇪 · Jean-Christophe David🇫🇷 · Sylvie Leray🇫🇷 · Jorge Lerendegui-Marco🇪🇸 · Cristian Massimi🇮🇹 · Vasilis Vlachoudis🇨🇭

   We use particle-transport simulations to show that secondary pions play a crucial role for the development of the hadronic cascade and therefore for the production of neutrons and photons from thick spallation targets. In particular, for the n_TOF lead spallation target, irradiated with 20 GeV/c protons, neutral pions are involved in the production of ~90% of the high-energy photons; charged pions participate in ~40% of the integral neutron yield. Nevertheless, photon and neutron yields are shown to be relatively insensitive to large changes of the average pion multiplicity in the individual spallation reactions. We characterize this robustness as a peculiar property of hadronic cascades in thick targets.

   ↳ nucl-thnucl-exEPJA(2017)·19 citations
4. 04*

   Simulations of a multi-layer extended gating grid

   J.D. Mulligan🇺🇸

   A novel idea to control ion back-flow in time projection chambers is to use a multi-layer extended gating grid to capture back-flowing ions at the expense of live time and electron transparency. In this initial study, I perform simulations of a four-layer grid for the ALICE and STAR time projection chambers, using $\text{Ne}-{\text{CO}}_2(90-10)$ and $\text{Ar}-{\text{CH}}_4(90-10)$ gas mixtures, respectively. I report the live time and electron transparency for both 90% and 99% ion back-flow suppression. Additionally, for the ALICE configuration I study several effects: using a mesh vs. wire-plane grid, including a magnetic field, and varying the over-voltage distribution in the gating region. For 90% ion back-flow suppression, I achieve 75% live time with 86% electron transparency for ALICE, and 95% live time with 83% electron transparency for STAR.

   ↳ physics.ins-detnucl-ex2 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.