High transverse momentum identified particle spectra in 200 GeV collisions from STAR

Abstract

Significant baryon over meson enhancement was measured at RHIC in the intermediate transverse momentum range of $p_T=2-4$ GeV/$c$ ("baryon-meson puzzle"). With STAR detector we were able to extend particle identification towards higher transverse momentum offering further insights into the particle production mechanisms at intermediate to high $p_T$. In this paper we present results on charged pion, proton and anti-proton spectra and ratios at intermediate to high $p_T$ exploiting the relativistic rise of the specific ionization energy loss measured in the STAR Time Projection Chamber. These measurements provide valuable information about the production mechanisms of particles at intermediate $p_T$ in relativistic heavy ion collisions, e.g. coalescence/recombination versus jet fragmentation.