ICHEP 2014

2-9 July 2014
Valencia, Spain

QCD analysis and effective temperature of direct photons in lead-lead collisions at the LHC

5 Jul 2014, 16:20
20m
Sala 2 ()

Sala 2

Oral presentation Heavy Ion Physics

Speaker

Prof. Michael Klasen (Institute for Theoretical Physics, University of Münster)

Description

We present a rigorous theoretical analysis of the ALICE measurement of low-p_T direct-photon production in central lead-lead collisions at the LHC with a centre-of-mass energy of \sqrt{s_{NN}}=2.76 TeV. Using NLO QCD, we compute the relative contributions to prompt-photon production from different initial and final states and the theoretical uncertainties coming from independent variations of the renormalisation and factorisation scales, the nuclear parton densities and the fragmentation functions. Based on different fits to the unsubtracted and prompt-photon subtracted ALICE data, we consistently find T = 304 \pm 58 MeV and 309 \pm 64 MeV for the effective temperature of the quark-gluon plasma (or hot medium) at p_T \in [0.8;2.2] GeV and p_T \in [1.5;3.5] GeV as well as a power-law (p_T^{-4}) behavior for p_T > 4 GeV as predicted by QCD hard scattering.

Primary author

Prof. Michael Klasen (Institute for Theoretical Physics, University of Münster)

Presentation Materials

 Paper Slides

Paper

Your browser is out of date!

Update your browser to view this website correctly. Update my browser now

×