Light Particle and Quark Chemical Potentials from Negatively to Positively Charged Particle Yield Ratios Corrected by Removing Strong and Weak Decays

Abstract

The yield ratios of negatively to positively charged pions (π − /π + ), negatively to positively charged kaons (K − /K + ), and anti-protons to protons (p/p) produced in mid-rapidity interval in central gold-gold (Au-Au) collisions, central lead-lead (Pb-Pb) collisions, and inelastic (INEL) or non-single-diffractive (NSD) proton-proton (pp) collisions, as well as in forward rapidity region in INEL pp collisions are analyzed in the present work. Over an energy range from a few GeV to above 10 TeV, the chemical potentials of light flavor particles (pion, kaon, and proton) and quarks (up, down, and strange quarks) are extracted from the mentioned yield ratios in which the contributions of strong decay from high-mass resonance and weak decay from heavy flavor hadrons are removed. Most energy dependent chemical potentials show the maximum at about 4 GeV, while the energy dependent yield ratios do not show such an extremum.

A New Description of Transverse Momentum Spectra of Identified Particles Produced in Proton-Proton Collisions at High Energies

“…These results are excluded the contributions from resonance decays [59]. Although the resonance decays contribute considerably to the yields of negative and positive hadrons, they contribute to the yield ratios and then the chemical potentials being small [52,53]. Before summary and conclusions, it should be pointed out that the data sets analyzed by us are in a narrow and low-p T range, which obey the standard distribution.…”

“…In the above discussions, although chemical potential µ runs through the entire process, it is an insensitive quantity in the fit, and not a free parameter due to the fact that it depends on T ch and k j . Our previous work [52,53] shows that, from 6.3 to 17.3 GeV, µ π + , µ K + , and µ p are around 0.041-0.017, 0.110-0.042, and 0.510-0.180 GeV, respectively, which are directly used in this work. These results are excluded the contributions from resonance decays [59].…”

“…Considering the yield ratio [k j (j = π, K, and p)] of negative to positive charged hadrons (j − to j + ), the corresponding chemical potentials (µ j − and µ j + ), as well as the corresponding source temperature (T j − and T j + ), one has the relationship between k j and µ j to be [20,[50][51][52][53]…”

“…Obviously, µ j is energy dependent due to T j and k j being energy dependent. Based on a collection of large amounts of experimental data, our previous work [52,53] presents the excitation functions of µ j in pp and central heavy ion collisions, which can be used for a direct extraction for this study. In particular, µ j decreases quickly with the increase of energy in pp collisions in the concerned SPS energy range.…”

Rapidity and Energy Dependencies of Temperatures and Volume Extracted from Identified Charged Hadron Spectra in Proton–Proton Collisions at a Super Proton Synchrotron (SPS)

“…Considering the yield ratio [k j (j = π, K, and p)] of negatively to positively charged hadrons (j − to j + ), the corresponding chemical potentials (µ j − and µ j + ), and the corresponding source temperature (T j − and T j + ), one has that the relationship between k j and µ j is [20,[50][51][52][53]…”