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Nuclear Theory·nucl-th

Wednesday·April 6, 2016

9 papers—7 primary·2 cross-listed

All9Primary7Cross-lists2
  1. 08

    Jet-like Correlations with Direct-Photon and Neutral-Pion Triggers at GeV

    STAR Collaboration

    Azimuthal correlations of charged hadrons with direct-photon () and neutral-pion () trigger particles are analyzed in central Au+Au and minimum-bias collisions at GeV in the STAR experiment. The charged-hadron per-trigger yields at mid-rapidity from central Au+Au collisions are compared with collisions to quantify the suppression in Au+Au collisions. The suppression of the away-side associated-particle yields per trigger is independent of the transverse momentum of the trigger particle (), whereas the suppression is smaller at low transverse momentum of the associated charged hadrons (). Within uncertainty, similar levels of suppression are observed for and triggers as a function of (). The results are compared with energy-loss-inspired theoretical model predictions. Our studies support previous conclusions that the lost energy reappears predominantly at low transverse momentum, regardless of the trigger energy.

    ↳ nucl-exhep-exhep-phnucl-thPLB(2016)·91 citations
  2. 09

    QCD topological susceptibility from the nonlocal chiral quark model

    Seung-il Nam🇰🇷 · Chung-Wen Kao🇹🇼

    We investigate the QCD topological susceptibility by using the nonlocal chiral quark model (NLQM). This model is based on the liquid instanton QCD-vacuum configuration in which flavor symmetry is explicitly broken by the current quark mass MeV. To compute , the local topological charge density operator is derived from the effective partition function of NLQM. We take into account the contributions from the leading-order (LO) ones in the expansion. We also verify that the analytical expression of in NLQM satisfy the Witten-Veneziano (WV) and the Leutwyler-Smilga (LS) formulae. Once the average instanton size and inter-instanton distance are fixed with fm and fm, respectively, all the associated model parameters are all determined self-consistently within the model, including the and weak decay constants. We obtain the results such as MeV and MeV for instance. Numerically we observe that in our full calculation. This value is comparable with its empirical one . We also find that our in the quenched limit and in the chiral limit. Consequently, we conclude that . Our result also implies that the decrease with the dynamical quark contributions.

    ↳ hep-phhep-latnucl-thJ.Korean Phys.Soc.(2017)·0 citations

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first authorsco-authorsvia INSPIRE