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arXiv · 2203.16204

Geometrical Scaling of Direct Photons in Relativistic Heavy Ion and d+Au Collisions

Vladimir Khachatryan·Michal Praszalowicz
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Abstract

In this paper, we show that multiplicity spectra of direct photons in A+A and d+Au collisions at different centrality classes and different energies exhibit geometrical scaling, {\em i.e.}, they depend on a specific combination of number of participants $N_{\rm part}$, collisions energy $W$, and transverse momentum $p_{T}$ -- called saturation scale -- rather than on all these three variables separately. In particular, the dependence on the geometry of collisions encoded in the dependence on $N_{\rm part}$ is in agreement with the expectations based on the Color Glass Condensate theory.

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Vladimir Khachatryan, Michal Praszalowicz. 2022-03-30. Geometrical Scaling of Direct Photons in Relativistic Heavy Ion and d+Au Collisions. https://doi.org/10.1016/j.nuclphysa.2023.122655

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