# Quark Matter 2014 - XXIV International Conference on Ultrarelativistic Nucleus-Nucleus Collisions

19-24 May 2014
Europe/Zurich timezone

## Study of high-$p_{\rm T}$ neutral mesons with a high energy photon trigger at ALICE

20 May 2014, 16:30
2h

Board: E-40
Poster Jets

### Speaker

Satoshi Yano (Hiroshima University (JP))

### Description

ALICE is one of the experiments at LHC and is mainly dedicated for heavy-ion collisions to investigate properties of a deconfined state of matter, Quark-Gluon Plasma (QGP). High $p_{\rm T}$ particle production is expected to be a powerful tool to study the QGP. The hadron yields in nucleus-nucleus collisions can be quantified by the nuclear modification factor, which is the ratio of the particle yield in A-A collisions normalized to the number of inelastic nucleon-nucleon collisions to the yield in pp collisions. The $R_{\rm AA}$ at high $p_{\rm T}$ is significantly smaller than 1, which can be interpreted by the parton energy loss. The ALICE experiment has a high resolution and high granularity photon spectrometer PHOS which deploys a specific trigger to enhance the high-$p_{\rm T}$ photon and neutral pion detection capability. Neutral pion production in pp collisions at $\sqrt{s}=8$ TeV has been studied. PHOS triggered data is used in this data analysis. With using this PHOS triggered data taken in 2012, neutral pion can be measured up to 40 GeV/c. To evaluate the production cross-section of the neutral pions with PHOS triggered data, trigger response of the PHOS needs to be understood as a function of the reconstructed cluster energy. A way to evaluate the trigger response utilizing the minimum-bias data as a function of the cluster energy has been developed. Neutral pion trigger efficiency is then estimated with simulation. A method to evaluate the rejection factor with real data is developed. These techniques can be applied to other collision systems, too. In this presentation, the status of analysis of the PHOS triggered data in pp collisions at $\sqrt{s}$ = 8 TeV will be presented.
On behalf of collaboration: ALICE

### Primary author

Satoshi Yano (Hiroshima University (JP))

 Poster