Seminaires des doctorants (1/4): Yaxian Mao

Thursday 8 Apr 2010, 11:30 → 12:00 Europe/Paris

amphi (LPSC)

The measurement of γ+jet pairs in heavy-ion collisions provides uniquely the tomographic image of the medium created in the collision. The tomographic image results from the interaction of hard scattered partons with the medium. The experimental technique consists in tagging events with a well identified high energy direct photon and in measuring the distribution of hadrons emitted oppositely to the photon as a function of the parameter, X_E=-p_T^h \cdot p_T^\gamma / |p_T^\gamma|^2. We have demonstrated that this method allows us to determine, with a good approximation, both the jet fragmentation function and the back-to-back azimuthal misalignment of the direct photon and the jet. Comparing these two observables measured in pp collisions with the ones measured in AA collisions will reveal the modifications induced by the medium of the jet structure and consequently will allow us to infer the medium properties. We have established the feasibility of such a measurement with the ALICE experiment in pp and heavy ion collisions at LHC.

Slides YMao.pdf