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arXiv · 0902.4000

Tomography of high-energy nuclear collisions with photon-hadron correlations

Hanzhong Zhang·J. F. Owens·Enke Wang·Xin-Nian Wang
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Abstract

Within the next-to-leading order (NLO) perturbative QCD (pQCD) parton model, suppression of away-side hadron spectra associated with a high $p_{T}$ photon due to parton energy loss is studied in high-energy heavy-ion collisions. Dictated by the shape of the $γ$-associated jet spectrum in NLO pQCD, hadron spectra at large $z_T=p_T^{h}/p_T^γ \stackrel{>}{\sim} 1$ are more sensitive to parton energy loss and therefore are dominated by surface emission of $γ$-associated jets, whereas small $z_{T}$ hadrons mainly come from fragmentation of jets with reduced energy which is controlled by the volume emission. These lead to different centrality dependence of the $γ$-hadron suppression for different values of $z_{T}$. Therefore, a complete measurement of the suppression of $γ$-triggered hadron spectra, including its dependence on the orientation of the $γ$-hadron pair with respect to the reaction plane, allows the extraction of the spatial distribution of jet quenching parameters, achieving a true tomographic study of the quark-gluon plasma in high-energy heavy-ion collisions.

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Hanzhong Zhang, J. F. Owens, Enke Wang, Xin-Nian Wang. 2009-02-23. Tomography of high-energy nuclear collisions with photon-hadron correlations. https://doi.org/10.1103/physrevlett.103.032302

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