Meson spectra andmTscaling inp+p,d+ Au, and Au + Au collisions atsNN=200GeV

Abstract

The meson spectra provide insight into the particle production mechanism and interaction in the hadronic and quark gluon plasma (QGP) phases. The detailed study of systematics of meson spectra is important also because it acts as an ingredient for estimating the hadronic decay backgrounds in the photon, single lepton, and dilepton spectra which are the penetrating probes of quark gluon plasma. In this work, we parametrize experimentally measured pion spectra and then obtain the spectra of other light mesons using a property known as ${m}_{T}$ scaling. The ${m}_{T}$ scaled spectra for each meson is compared with experimental data for $p+p$, $d$ + Au, and Au + Au systems at $\ensuremath{\surd}{s}_{NN}$ = 200 GeV. The agreement of the ${m}_{T}$ scaled and experimental data shapes are excellent in most cases and their fitted relative normalization gives ratio of meson to pion ${m}_{T}$ spectra. These ratios are useful to obtain the hadronic decay contribution in photonic and leptonic channels but also point to the quantitative changes in the dynamics of the heavy ion collision over $p+p$ collisions. It is shown that, the particles with charm contents behave differently as compared to pions in $d$ + Au systems and particles either with strange or charm contents behave differently from pions in Au + Au systems. For Au + Au system, three centrality classes have been studied which reveal that for the particles, such as kaon and $\ensuremath{\varphi}$, peripheral collision data are better reproduced as compared to central collision data and their relative ratios with pions also increase as the collisions become more central.