$\eta$ meson production of high-energy nuclear collisions at NLO

TL;DR

This paper investigates $ ext{eta}$ meson production in high-energy nuclear collisions using NLO perturbative QCD, incorporating jet quenching effects, and compares predictions with experimental data from RHIC and LHC.

Contribution

It introduces a NLO perturbative QCD framework with medium-modified fragmentation functions to describe $ ext{eta}$ meson spectra in heavy-ion collisions, aligning well with experimental data.

Findings

Theoretical simulations match PHENIX data for $ ext{eta}$ in p+p and Au+Au collisions.

The $ ext{eta}/ ext{pi}^0$ ratio approaches the e+e- scattering value at high $p_T$.

Predictions for $ ext{eta}/ ext{pi}^0$ at LHC energies are provided.

Abstract

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 $\rm p+p$ and central $\rm Au+Au$ collisions at the RHIC, and also provide numerical predictions of $\eta$ spectra in central $\rm Pb+Pb$ collisions with $\sqrt{s_{NN}}=2.76$~TeV at the LHC. The ratios of $\eta/\pi^0$ in $\rm p+p$ and in central $\rm Au+Au$ 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 $p_{T} \rightarrow \infty$ the ratios of $\eta/\pi^{0}$ in both $\rm Au+Au$ and $\rm p+p$ 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 $p_T$ region in $\rm A+A$ relative to that in $\rm p+p$; while a slightly higher $\eta/\pi^{0}$ at small $p_T$ in $\rm Au+Au$ 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.