η meson production of high-energy nuclear collisions at NLO

The transverse momentum spectrum of eta meson in relativistic heavy-ion collisions is studied at the Next-to-Leading Order (NLO) within the perturbative QCD, where the jet quenching effect in the QGP is incorporated with the effectively medium-modified eta fragmentation functions using the higher-twist approach. We show that the theoretical simulations could give nice descriptions of PHENIX data on eta meson in both p + p and central Au + Au collisions at the RHIC, and also provide numerical predictions of eta spectra in central Pb + Pb collisions with root s(NN) = 2.76 TeV at the LHC. The ratios of eta/pi(0) in p + p and in central Au + Au collisions at 200 GeV are found to overlap in a wide p(T) region, which matches well the measured ratio eta/pi(0) by PHENIX We demonstrate that, at the asymptotic region when p(T) -> infinity the ratios of eta/pi(0) in both Au + Au and p + p are almost determined only by quark jets fragmentation and thus approach to the one in e(+)e(-) scattering; in addition, the almost identical gluon (quark) contribution fractions to eta and to pi result in a rather moderate variation of eta/pi(0) distribution at intermediate and high PT region in A + A relative to that in p + p; while a slightly higher eta/pi(0) at small PT in Au + Au can be observed due to larger suppression of gluon contribution fraction to pi(0) as compared to the one to eta. The theoretical prediction for eta/pi(0) at the LHC has also been presented. (C) 2015 The Authors. Published by Elsevier B.V.