Speaker
Daiki Sekihata
(Hiroshima University (JP))
Description
A state of deconfined quarks and gluons, called quark-gluon plasma (QGP), is created in high-energy heavy-ion collisions.
The ALICE experiment is mainly devoted to the study of heavy-ion collisions produced at the LHC to investigate such the new state of matter.
Neutral mesons such as $\pi^{0}$ and $\eta$ that decay into two photons are suitable to study parton energy loss in the QGP, since they can be identified, using a fine-segmented electromagnetic calorimeter, in a wide transverse momentum range.
The Photon Spectrometer (PHOS) in the ALICE is an electromagnetic calorimeter, located at 4.6 m from the interaction point, consisted of 10,752 segments with a $2.2 \times 2.2\times 18 \ {\rm cm}^{3}$ $\rm PbWO_{4}$ crystal read out by an APD.
This fine granularity allows us to distinguish two photons decayed in a small opening angle from a parent particle at a high transverse momentum.
I am analyzing the Pb-Pb data at $\sqrt{s_{\rm NN}}$ = 2.76 TeV recorded in 2011 with an integrated luminosity 100 ${\rm \mu b^{-1}}$ and detected with centrality triggers.
Clear $\pi^{0}$ peak was extracted in a wide $p_{\rm T}$ range and each centrality class via di-photon channel with the PHOS detector in ALICE.
I will report the current status of my analysis, namely event selections, acceptances, efficiencies and invariant mass spectra with two photons up to 40 ${\rm GeV}/c$.
| On behalf of collaboration: | ALICE |
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Primary author
Daiki Sekihata
(Hiroshima University (JP))
