Fri·Jan 25, 2019Friday·January 25, 2019

1. 01*

   Azimuthal harmonics in small and large collision systems at RHIC top energies

   STAR Collaboration: J. Adam🇺🇸 · L. Adamczyk🇵🇱 · J. R. Adams🇺🇸 · J. K. Adkins🇺🇸 · G. Agakishiev🇷🇺 · M. M. Aggarwal🇮🇳 · Z. Ahammed🇮🇳 · I. Alekseev🇷🇺 · D. M. Anderson🇺🇸 · R. Aoyama🇯🇵 · A. Aparin🇷🇺 · D. Arkhipkin🇺🇸 and 331 other authors

   The first ($v_1^{\text{even}}$), second ($v_2$) and third ($v_3$) harmonic coefficients of the azimuthal particle distribution at mid-rapidity, are extracted for charged hadrons and studied as a function of transverse momentum ($p_T$) and mean charged particle multiplicity density $⟨{\mathrm{N}}_{\mathrm{ch}}⟩$ in U+U ($\text{roots}=193$~GeV), Au+Au, Cu+Au, Cu+Cu, $d$+Au and $p$+Au collisions at $\text{roots}=200$~GeV with the STAR Detector. For the same $⟨{\mathrm{N}}_{\mathrm{ch}}⟩$, the $v_1^{\text{even}}$ and $v_3$ coefficients are observed to be independent of collision system, while $v_2$ exhibits such a scaling only when normalized by the initial-state eccentricity (${\epsilon }_2$). The data also show that $\ln (v_2/{\epsilon }_2)$ scales linearly with $⟨{\mathrm{N}}_{\mathrm{ch}}{⟩}^{-1/3}$. These measurements provide insight into initial-geometry fluctuations and the role of viscous hydrodynamic attenuation on $v_n$ from small to large collision systems.

   nucl-exnucl-thPRL(2019)·71 citations
2. 02*

   Strangeness Enhancement in p+p, p+Pb and Pb+Pb Collisions at LHC Energies

   Y. Kanakubo🇯🇵 · M. Okai🇯🇵 · Y. Tachibana🇺🇸 · T. Hirano🇯🇵

   We investigate whether the quark gluon plasma (QGP) is created in small colliding systems from analyses of various hadron yields and their ratios in proton-proton (p+p), proton-lead (p+Pb) and lead-lead (Pb+Pb) collisions at LHC energies. Recently, the ALICE Collaboration reports enhancement of yield ratio of multi-strange hadrons to charged pions as a function of multiplicity at mid-rapidity. Motivated by these results, we develop the dynamical core-corona initialization framework and find that our results describe tendencies of the ALICE data especially for multi-strange hadrons. These results indicate that the QGP is partly formed in high multiplicity events in small colliding systems.

   ↳ nucl-thhep-phnucl-exJPS Conf.Proc.(2019)·3 citations
3. 03*

   Measurement of charm and bottom production from semileptonic hadron decays in $p$$+$$p$ collisions at $\sqrt{s_{NN}}=200$ GeV

   C. Aidala · Y. Akiba · M. Alfred · V. Andrieux · N. Apadula · H. Asano · B. Azmoun · V. Babintsev · N.S. Bandara · K.N. Barish · S. Bathe · A. Bazilevsky and 291 other authors

   Measurements of the differential production of electrons from open-heavy-flavor hadrons with charm- and bottom-quark content in $p$$+$$p$ collisions at $\sqrt{s}=200$ GeV are presented. The measurements proceed through displaced-vertex analyses of electron tracks from the semileptonic decay of charm and bottom hadrons using the PHENIX silicon-vertex detector. The relative contribution of electrons from bottom decays to inclusive heavy-flavor-electron production is found to be consistent with fixed-order-plus-next-to-leading-log perturbative-QCD calculations within experimental and theoretical uncertainties. These new measurements in $p$$+$$p$ collisions provide a precision baseline for comparable forthcoming measurements in A$+$A collisions.

   ↳ hep-exnucl-exPRD(2019)·22 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.