Fri·Sep 12, 2014Friday·September 12, 2014

1. 01*

   Beam energy dependence of charged pion ratio in ${}^{28}$Si + In reactions

   M. Sako🇺🇸 · T. Murakami🇯🇵 · Y. Nakai · Y. Ichikawa🇯🇵 · K. Ieki🇯🇵 · S. Imajo · T. Isobe🇯🇵 · M. Matsushita🇯🇵 · J. Murata🇯🇵 · S. Nishimura🇯🇵 · H. Sakurai🇯🇵 · R.D. Sameshima🇺🇸 · E. Takada

   The double differential cross sections for ${}^{nat}$In(${}^{28}$Si, ${\pi }^{\pm }$) reactions are measured at 400, 600, and 800 MeV/nucleon. Both ${\pi }^{+}$ and ${\pi }^{-}$ are found to be emitted isotropically from a single moving source. The ${\pi }^{-}/{\pi }^{+}$ yield ratio is determined as a function of the charged pion energy between 25 and 100 MeV. The experimental results significantly differ from the prediction of the standard transport model calculation using the code PHITS. This discrepancy suggests that more theoretical works are required to deduce firm information on the nuclear symmetry energy from the ${\pi }^{-}/{\pi }^{+}$ yield ratio.

   nucl-ex3 citations
2. 02*

   Long-range two-particle correlations of strange hadrons with charged particles in pPb and PbPb collisions at LHC energies

   CMS Collaboration

   Measurements of two-particle angular correlations between an identified strange hadron (K0S or Lambda/anti-Lambda) and a charged particle, emitted in pPb collisions, are presented over a wide range in pseudorapidity and full azimuth. The data, corresponding to an integrated luminosity of approximately 35 inverse nanobarns, were collected at a nucleon-nucleon center-of-mass energy (sqrt(s[NN])) of 5.02 TeV with the CMS detector at the LHC. The results are compared to semi-peripheral PbPb collision data at sqrt(s[NN]) = 2.76 TeV, covering similar charged-particle multiplicities in the events. The observed azimuthal correlations at large relative pseudorapidity are used to extract the second-order (v[2]) and third-order (v[3]) anisotropy harmonics of K0S and Lambda/anti-Lambda particles. These quantities are studied as a function of the charged-particle multiplicity in the event and the transverse momentum of the particles. For high-multiplicity pPb events, a clear particle species dependence of v[2] and v[3] is observed. For pt < 2 GeV, the v[2] and v[3] values of K0S particles are larger than those of Lambda/anti-Lambda particles at the same pt. This splitting effect between two particle species is found to be stronger in pPb than in PbPb collisions in the same multiplicity range. When divided by the number of constituent quarks and compared at the same transverse kinetic energy per quark, both v[2] and v[3] for K0S particles are observed to be consistent with those for Lambda/anti-Lambda particles at the 10% level in pPb collisions. This consistency extends over a wide range of particle transverse kinetic energy and event multiplicities.

   nucl-exhep-exPLB(2015)·180 citations
3. 03*

   Heavy flavor production in the STAR experiment

   Barbara Trzeciak (for the STAR Collaboration)🇨🇿

   In this paper, recent STAR heavy flavor measurements in proton-proton and heavy-ion collisions are highlighted. We report studies of open charm mesons, reconstructed directly from hadronic decay products, and studies of electrons from semi-leptonic decays of heavy flavor hadrons. We also present J/$\psi$ measurements via the di-electron decay channel at various collision systems and energies. In Au+Au collisions the energy dependence of J/$\psi$ production measured at $\sqrt{s_{NN}}$ = 39, 62.4 and 200 GeV is shown. Finally, prospects of heavy flavor measurements with the STAR detector upgrades are discussed.

   nucl-exJ.Phys.Conf.Ser.(2014)·0 citations
4. 04*

   Inclusive Jet Spectra in p-Pb Collisions at ALICE

   Megan Connors (for the ALICE Collaboration)🇺🇸

   Jet suppression has been observed in central heavy ion collisions. This suppression is attributed to partonic energy loss in the Quark Gluon Plasma (QGP) formed in such collisions. However, this measurement is influenced by all stages of the collision. It is expected that in p-Pb collisions similar initial conditions occur as in Pb-Pb collisions without creating a QGP, allowing modification to the jet spectra due to cold nuclear matter effects to be quantified. Inclusive jet spectra in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV measured by ALICE are presented. Jets are reconstructed via the anti-k${}_{\mathrm{T}}$ algorithm with different resolution parameters by combining charged tracks measured in the ALICE tracking system with the neutral energy deposited in the electromagnetic calorimeter. The jet spectra can be used to determine a nuclear modification factor $R_{\mathrm{pPb}}$ while the jet profile in p-Pb is studied by dividing spectra measured with different resolution parameters and comparing to the same ratio measured in pp collisions.

   nucl-exNPA(2014)·7 citations
5. 05*

   Strangeness production in two-particle azimuthal correlations on the near and away side measured with ALICE in pp collisions at 7 TeV

   Sandun Jayarathna (for the ALICE Collaboration)🇺🇸

   Two-particle azimuthal correlations allow one to study high-$p_{\mathrm{T}}$ parton fragmentation without full jet reconstruction. Enhancements of the azimuthal correlations are seen at $\Delta \phi \approx 0$ and $\Delta \phi \approx \pi$, resulting from back-to-back jet fragmentation in the parton center-of-mass system. We present the current status of the study of correlations between charged trigger particles and associated strange baryons ($\Lambda$) and mesons (K${}_S^0$) in pp collisions at $\sqrt{s}$ = 7 TeV. A data-driven feeddown correction for $\Lambda$ is also presented, which could allow a more accurate calculation of the primary $\Lambda /$K${}_S^0$ ratio in jets and the underlying event.

   nucl-ex1 citation
6. 06*

   Comment on "Fitting the annual modulation in DAMA with neutrons from muons and neutrinos''

   P.S. Barbeau🇺🇸 · J.I. Collar🇺🇸 · Yu. Efremenko🇺🇸 · K. Scholberg🇺🇸

   We estimate rates of solar neutrino-induced neutrons in a DAMA/LIBRA-like detector setup, and find that the needed contribution to explain the annual modulation would require neutrino-induced neutron cross sections several orders of magnitude larger than current calculations indicate. Although these cross sections have never been measured, it is likely that the solar-neutrino effect on DAMA/LIBRA is negligible.

   ↳ hep-phastro-ph.COhep-exnucl-exPRL(2014)·16 citations
7. 07*

   Dissipative dynamics in quasi-fission

   V.E. Oberacker🇺🇸 · A.S. Umar🇺🇸 · C. Simenel🇦🇺

   Quasi-fission is the primary reaction mechanism that prevents the formation of superheavy elements in heavy-ion fusion experiments. Employing the time-dependent density functional theory approach we study quasi-fission in the systems ${}^{40,48}$Ca+${}^{238}$U. Results show that for ${}^{48}$Ca projectiles the quasi-fission is substantially reduced in comparison to the ${}^{40}$Ca case. This partly explains the success of superheavy element formation with ${}^{48}$Ca beams. For the first time, we also calculate the repartition of excitation energies of the two fragments in a dynamic microscopic theory. The system is found in quasi-thermal equilibrium only for reactions with ${}^{40}$Ca. The differences between both systems are interpreted in terms of initial neutron to proton asymmetry of the colliding partners.

   ↳ nucl-thnucl-exPRC(2014)·95 citations
8. 08*

   Isotopic ratio, isotonic ratio, isobaric ratio and Shannon information uncertainty

   Chun-Wang Ma🇨🇳 · Hui-Ling Wei🇨🇳

   The isoscaling and the isobaric yield ratio difference (IBD) probes, which both are constructed by yield ratio of fragment, provide cancelation of parameters. The information entropy theory is introduced to explain the physical meaning of the isoscaling and IBD probes. The similarity between the isoscaling and IBD results is found, i.e., the information uncertainty determined by the IBD method equals to $\beta -\alpha$ determined by the isoscaling [$\alpha$ ($\beta$) is the parameter fitted from the isotopic (isotonic) yield ratio].

   ↳ nucl-thnucl-exCommun.Theor.Phys.(2014)·9 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.