Spectra and elliptic flow of thermal photons from full-overlap U+U collisions at energies available at the BNL Relativistic Heavy Ion Collider

Abstract

We calculate pT spectra and elliptic flow for tip-tip and body-body configurations of full overlap uranium-uranium (U+U) collisions using a hydrodynamic model with smooth initial density distribution and compare the results with those obtained from Au+Au collisions at RHIC. Production of thermal photons is seen to be significantly larger for tip-tip collisions compared to body-body collisions of uranium nuclei in the region pT > 1 GeV. The difference in the results for the two configurations of U+U collisions depends on the initial energy deposition which is yet to be constrained precisely from hadronic measurements. The thermal photon spectrum from body-body collisions is found to be close to the spectrum from most central Au+Au collisions at RHIC. The elliptic flow parameter calculated for body-body collisions is found to be large and comparable to the v2(pT ) for mid-central collisions of Au nuclei. On the other hand, as expected, the v2(pT ) is close to zero for tip-tip collisions. The qualitative nature of the photon spectra and elliptic flow for the two different orientations of uranium nuclei is found to be independent of the initial parameters of the model calculation. We show that the photon results from fully overlapping U+U collisions are complementary to the results from Au+Au collisions at RHIC.

Anisotropic flow of photons in relativistic heavy ion collisions

“…Earlier studies have shown that photon elliptic flow increases significantly in the region p T > 2 GeV when the formation time τ 0 is changed from 0.2 fm/c to 0.6 fm/c in the hydrodynamical model calculation [15,35]. The triangular flow parameter of photons is also shows similar (to the elliptic flow parameter) τ 0 dependent behaviour [21].…”

Electroweak Physics: Summary

“…The fully overlapping U+U collisions can lead to different collision geometry depending on the orientation of the colliding nuclei. A recent study using hydrodynamical model calculation has shown that the photon production from tip-tip configuration of U+U collisions is comparable to the production from most central Au+Au collisions at RHIC [18]. On the other hand, the elliptic flow from body-body configuration of uranium nuclei is found to be close to the photon v 2 from midcentral Au+Au collisions.…”

“…The experimental data from a number of small and large systems as well as from different beam energies have opened up the possibility of understanding the initial state as well as the photon puzzle better. Additionally, photon production from asymmetric collisions (C+Au) [17] and also from collisions of deformed nuclei (U+U) [18] can play an important role in this regard.…”

Exploring the effect of hadron cascade-time on particle production in Xe+Xe collisions at $\sqrt{s_{\rm{NN}}}$ = 5.44 TeV through a multi-phase transport model

“…We use Woods-Saxon (WS) [21] distribution to define the distribution of nucleons inside the spherical nuclei like Au and Pb. Whereas, for the deformed nuclei like Xenon, we have used a modified Woods-Saxon (MWS) density distribution in the HIJING that includes deformation parameter, β n , along with spherical harmonics, Y nl (θ), in the WS function [22][23][24][25][26]. Nucleon density is usually written as a three parameter Fermi distribution [27], which is defined as,…”