Precision identified-hadron spectrum analysis for 5 TeV $\bf p$-$\bf Pb$ collisions -- Part II

Abstract

This is the second part of a two-part article on precision modeling of identified-hadron (PID) $p_t$ spectra from 5 TeV $p$-Pb collisions. In Part I a revised two-component (soft + hard) model (TCM) of PID spectra was introduced, an apparent detection inefficiency for protons was corrected and jet-related spectrum hard components isolated via an improved method were compared to a fixed TCM serving as reference. In the present article (Part II) the TCM is further elaborated to describe centrality variation of spectrum hard components (and therefore entire spectra) within data statistical uncertainties as determined by a standard statistical measure (Z-scores). The completed PID TCM is then used to investigate properties of spectrum and yield ratios (e.g. $p/\pi$ ratios) and ensemble-mean $\bar p_t$ data. Systematic differences are observed between meson and baryon hard components. With increasing $p$-Pb centrality meson hard components shift to lower $p_t$ while baryon hard components shift to higher $p_t$. Those trends explain quantitatively the main features and centrality variation of spectrum ratios. Ensemble-mean $\bar p_t$ trends are also predicted at the level of data statistical uncertainties, and details of the $\bar p_t$ centrality trends are explained quantitatively.