Speaker
Description
Particle ratio fluctuation is one of the observables which is expected to be enhanced during the phase transition that passes close to the critical point. The investigations involving particle ratio fluctuations may reveal the degrees of freedom of the strongly interacting matter created in heavy-ion collisions. Fluctuations in identified particle ratios, $ [\pi,k] $, $ [\pi,p] $, $ [k,p] $ at RHIC and LHC energies is studied in the framework of HYDJET++ model using the fluctuation measure $\nu_{dyn}$ and the findings are compared with the experimental results reported earlier. Events corresponding to Pb-Pb collisions at ${ \sqrt s_{NN}} = $ 2.76 and 5.02, Xe-Xe collisions $ \sqrt s_{NN} = $ 5.44 TeV and Au-Au collisions at $ \sqrt s_{NN} = $ 39, 100 and 200 GeV are simulated and analysed. The observed centrality dependence of the $\nu_{dyn}[a,b]$ for the three combination of particle pairs agree fairly well with those observed in ALICE experiments except for the peripheral collisions. At LHC energies, for peripheral collisions $\nu_{dyn}$ values for the three pairs are larger as compared to those reported for the data. However, at RHIC energies, $\nu_{dyn}$ values for $[k,p]$ and $[\pi,p]$ pairs, for peripheral collisions are negative, which indicate a correlation between these pairs. For central collisions, however, the values of the three pair combinations are positive and nearly energy independent. This is consistent with the poissonian expectation within $ 2\sigma$. The scaled values of $\nu_{dyn}$, plotted against charge particle density, exhibit a kind of scaling for $[\pi,k]$ and $[\pi,p]$ pairs for semi--central and central collisions, but exhibit somewhat different trend of variation than what has been observed with the model of independent nucleon-nucleon collisions.
| Field of contribution | Phenomenology |
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