Production and ratio ofπ,K,p, andΛin Pb + Pb collisions atsNN=2.76TeV

Abstract

The particle production and their ratios for $\ensuremath{\pi}$, $K$, $p$, and $\ensuremath{\Lambda}$ are studied in Pb + Pb collisions at $\sqrt{{s}_{NN}}\phantom{\rule{0.16em}{0ex}}=\phantom{\rule{0.16em}{0ex}}2.76$ TeV based on a blast-wave model with thermal equilibrium mechanism. The transverse momentum spectra of the above-mentioned particles at the kinetic freeze-out stage are discussed. The modification of the inverse slope of pion transverse momentum spectrum due to resonance decay has also been investigated. In addition, we found that the antiparticles-to-particles ratio as well as the kaons-to-pions ratio agree with the data by the LHC-ALICE Collaboration reasonably well, while the $p/\ensuremath{\pi}$ ratio is overestimated by a factor of 1.5, similar to those from other thermal model calculations. It is found that the ratios of $p/\ensuremath{\pi}$ and $K/\ensuremath{\pi}$ are dominated by the radial flow but slightly affected by the baryon chemical potential. Our study thus constrains the parameters at the chemical and kinetic freeze-out stages within the framework of thermal model in Pb + Pb collisions at $\sqrt{{s}_{NN}}\phantom{\rule{0.16em}{0ex}}=\phantom{\rule{0.16em}{0ex}}2.76$ TeV, and will help us better understand the properties of the dense and hot matter created in high-energy heavy-ion collisions at freeze-out stage.