4-8 July 2016
Kramer Law building
Africa/Johannesburg timezone
The Proceedings of SAIP2016 published on 24 December 2017
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Neutral meson and direct photon measurement with ALICE

Presented by Andile WHITEHEAD on 6 Jul 2016 from 15:20 to 15:40
Type: Oral Presentation
Track: Track B - Nuclear, Particle and Radiation Physics


The verification of the existence of the Quark-Gluon Plasma (QGP) produced in high energy heavy-ion collisions is a procedure requiring the measurement of several complementary observables. Among these observables, is the measurement of direct photons. The direct photon spectrum, at high p<sub>T</sub>, is expected to be dominated by prompt photons produced by hard initial scatterings in the earliest phases of the collision - describable using the methods of NLO pQCD - and at low p<sub>T</sub> by thermal photons produced in thermal scatterings in the QGP and hot hadronic gas phase. Neutral mesons, particularly &pi<sup>0</sup> and &eta mesons, are the dominant source of decay photons in pp and Pb-Pb collisions, and their precise measurement is required in order to disentangle the decay and direct photon signals within the inclusive photon spectrum. High-quality measurements in pp collisions are required as a reference for Pb-Pb collisions. The ALICE detector is capable of accurately measuring neutral meson spectra over a large p<sub>T</sub> range, via the use of several complementary measuring techniques. The Photon Conversion Method, discussed somewhat in detail in this presentation, uses the ITS and TPC subdetectors and is well suited to performing such measurements over low to intermediate p T . The PHOS and EMCal electromagnetic calorimeters on the other hand, are adept at performing measurements within the intermediate to high p T region. In this presentation, measurements of &pi<sup>0</sup>’s and &eta’s obtained from the ALICE experiment, for pp collisions at several collisional center of mass energies (√s<sub>NN</sub>), from √s = 0.9 TeV to 8 TeV and in Pb-Pb collisions at √s<sub>NN</sub> = 2.76 TeV, along with direct photon measurements will be presented.






Dr. Thomas Dietel






Location: Kramer Law building
Address: UCT Middle Campus Cape Town
Room: 4A

Primary authors