Ligth-flavour identified charged-hadron production in pp and Pb-Pb collisions at the LHC

Abstract

Thanks to the unique detector design adopted to fulfill tracking and particle-identification (PID) requirements (e.g. low momentum cut-off and low material budget), the ALICE experiment provides significant information about hadron production both in pp and Pb-Pb collisions. In particular, the $p_{\mathrm{T}}$-differential and integrated production yields of identified particles play a key role in the study of the collective and thermal properties of the matter formed in high-energy heavy-ion collisions. Furthermore, the production of high-$p_{\mathrm{T}}$ particles provides insights into the property of the hot medium created in such collisions and the in-medium energy-loss mechanisms. Transverse momentum spectra of ${\pi }^{\pm }$, K${}^{\pm }$, p and $\bar{\mathrm{p}}$ are measured at mid-rapidity ($\left|y\right|<0.5$) over a wide momentum range, from $\sim$~100 MeV/$c$ up to $\sim$~20 GeV/$c$. The current results on light-flavour charged-hadron production will be presented for pp collisions at $\sqrt{s}$ = 0.9, 2.76 and 7 TeV and for Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV. Integrated production yields, transverse momentum spectra and particle ratios in pp are discussed as a function of the collision energy and compared to previous experiments and commonly-used Monte Carlo models. Pb-Pb collisions at the LHC feature the highest radial flow ever observed and an unexpectedly low p/$\pi$ production ratio. The results are presented as a function of collision centrality and compared to RHIC data in Au-Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 200 GeV and predictions from thermal and hydrodynamic models. The nuclear modification factor ($R_{\mathrm{AA}}$) of identified hadrons will also be discussed and compared to unidentified charged particles and theoretical predictions. This is observed to be identical for all particle species at high-$p_{\mathrm{T}}$.

10 pages, 11 figures, prepared for the Proceedings of the International Workshop On Physics At The LHC (Kruger 2012) December 3 - 7, 2012 Protea Hotel, Kruger Gate South Africa

References in corpus (8)

• Centrality dependence of charged particle production at large transverse momentum in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV
• Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC
• Pion, kaon, and proton production in central Pb-Pb Collisions at $\sqrt{s_{NN}}=2.76$ TeV
• Transverse momentum distribution and nuclear modification factor of charged particles in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV
• The PHOBOS Glauber Monte Carlo
• Non-thermal p/pi ratio at LHC as a consequence of hadronic final state interactions
• Production of pions, kaons and protons at high pT in sqrt{s_NN}=2.76 TeV Pb-Pb collisions
• Baryon Annihilation and Regeneration in Heavy Ion Collisions

Cited by in corpus (3)

• Confronting current NLO parton fragmentation functions with inclusive charged-particle spectra at hadron colliders
• Investigating radial flow-like effects via pseudorapidity and transverse spherocity dependence of particle production in pp collisions at the LHC
• LHC data challenges the contemporary parton-to-hadron fragmentation functions