11–15 Dec 2017
Hotel Peterhoff, Shimla, India
Asia/Kolkata timezone

System size dependence of particle production in pp, p-Pb and Pb-Pb collisions at 5.02 TeV

12 Dec 2017, 12:15
15m
Conference Hall (Hotel Peterhoff, Shimla, India)

Conference Hall

Hotel Peterhoff, Shimla, India

Speaker

Dr Ajay Kumar Dash (National Institute of Science Education and Research, Jatni)

Description

The ALICE collaboration has measured the production of light-flavour hadrons in pp, p--Pb and Pb--Pb collisions at$\sqrt{s\rm{_{NN}}} = $ 5.02 TeV over a wide range of transverse momentum ($p_{\rm T}$). The results on $\pi$, K, p,K$^{*0}$ and $\phi$ $p_{\rm T}$ spectra, ratios of the $p_{\rm T}$-integrated yields and mean transverse momentum will be presented for the three colliding systems at the same energy ($\sqrt{s_{\rm{NN}}}$ = 5.02 TeV), and compared as a function of average charged particle multiplicity measured at mid-rapidity. It will be shown that the production of these particles follows a continuous trend as a function of multiplicity across the three systems. Identified particle ratios provide information on the composition and the thermal properties of the medium. The measurement of short-lived hadronic resonance production and their ratio to stable hadron species, such as $\phi/$K and K$^{*0}/$K, is used to infer information on the hadronic phase.

Parton energy loss is investigated by determining the nuclear modification factor ($R\mathrm{_{AA}}$). The production of light-flavour hadrons in the most central Pb--Pb collisions relative to pp collisions is found to be strongly suppressed at high $p\rm{_T}$ ($>$ 8 GeV/$c$), whereas in p--Pb collisions the nuclear modification factors are consistent with unity. This indicates that the strong suppression of high-$p\rm{_T}$ hadrons measured in central Pb--Pb collisions is not due to an initial state effect but instead to the energy loss of partons traversing a hot and dense QCD medium. A similar suppression is observed for all the measured light-flavour hadrons at $p\rm{_T}$ $>$ 8 GeV/$c$. This suggests that the partonic energy loss in the medium for light quark flavors ($u, d, s$) is independent of flavour.

Primary author

Dr Ajay Kumar Dash (National Institute of Science Education and Research, Jatni)

Presentation materials