# EPS HEP 2013 Stockholm

17-24 July 2013
KTH and Stockholm University Campus
Europe/Stockholm timezone

## Identified charged pion, kaon, and proton production in pp and Pb-Pb collisions at LHC energies measured with ALICE

18 Jul 2013, 11:00
16m
E2 (KTH Campus)

### E2

#### KTH Campus

Talk presentation Ultrarelativistic Heavy Ions

### Speaker

Peter Christiansen (Lund University (SE))

### Description

\begin{center} {\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. \vspace{12pt} $^{\rm a}$Department of Physics, Particle Physics, Lund University,\\ SE-221 00 Lund, Sweden,\\ \textit{peter.christiansen@hep.lu.se} \vspace{12pt} \vspace{12pt} \end{center} 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))

 Slides