Speaker
Peter Christiansen
(Lund University (SE))
Description
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{\large \bf Identified charged pion, kaon, and proton production in pp and Pb-Pb collisions at LHC energies measured with ALICE}
{\bf P.~Christiansen}$^{\rm a}$ for the ALICE Collaboration.
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$^{\rm a}$Department of Physics, Particle Physics, Lund
University,\\
SE-221 00 Lund, Sweden,\\
\textit{peter.christiansen@hep.lu.se}
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ALICE has unique capabilities among the LHC experiments for particle
identification (PID) at mid-rapidity ($|y| < 1$) over a wide range of
transverse momentum ($p_{\rm T}$). For $p_{\rm T}$ from 100 MeV/$c$ up to 3-4 GeV/$c$ (anti)protons, charged pions and kaons can be separated on a track-by-track basis through the measurement of the specific energy loss, d$E$/d$x$, and the time of flight. The identification of protons can be extended up to 6 GeV/$c$ by the Cherenkov detector. For $3 < p_{\rm T} < 20$~GeV/$c$, statistical PID can be done thanks to the relativistic rise of the d$E$/d$x$ in the TPC. In this talk,
the spectra for charged pions, kaons, and (anti)protons from pp (at $\sqrt{s} = 2.76$ and 7 TeV) and Pb-Pb (at $\sqrt{s_{\text{NN}}} = 2.76$ TeV) collisions will be presented.
The results from pp collisions are important both as a baseline for Pb-Pb measurements and for our understanding of the hadronization process with a focus here on jet fragmentation. \\ Low $p_{\rm T}$ results in Pb-Pb collisions provide information regarding bulk production and collective flow, and will be discussed in the context of the statistical model and hydrodynamic calculations. The intermediate $p_{\rm T}$ region is interesting due to the anomalous
large peak in the proton to pion ratio that can be an indication for new hadronization processes in Pb-Pb such as recombination. Finally, high $p_{\rm T}$ results provide insight into jet quenching via the nuclear modification factor, $R_{\text{AA}}$.
Primary author
Peter Christiansen
(Lund University (SE))
