Low-momentum direct photon measurement in Cu+Cu collisions at √.sup.s./sup.NN=200 GeV

0501762 - FZÚ 2019 RIV US eng J - Článek v odborném periodiku
Adare, A. - Afanasiev, S. - Aidala, C. - Tomášek, Lukáš - Růžička, Pavel - Vrba, Václav - Mikeš, P. - Kubart, J. - Mašek, L. … celkem 452 autorů
Low-momentum direct photon measurement in Cu+Cu collisions at √^sNN=200 GeV.
Physical Review C. Roč. 98, č. 5 (2018), s. 1-11, č. článku 054902. ISSN 2469-9985. E-ISSN 2469-9993
Institucionální podpora: RVO:68378271
Klíčová slova: photon * virtual * rapidity * density * mass spectrum * experimental equipment * experimental methods * experimental results
Obor OECD: Particles and field physics
Impakt faktor: 3.132, rok: 2018

We measured direct photons for pT<5GeV/c in minimum bias and 0%–40% most-central events at midrapidity for Cu+Cu collisions at sNN=200GeV. The e+e− contribution from quasireal direct virtual photons has been determined as an excess over the known hadronic contributions in the e+e− mass distribution. A clear enhancement of photons over the binary scaled p+p fit is observed for pT<4GeV/c in Cu+Cu data. The pT spectra are consistent with the Au+Au data covering a similar number of participants. The inverse slopes of the exponential fits to the excess after subtraction of the p+p baseline are 285±53(stat)±57(syst)MeV/c and 333±72(stat)±45(syst)MeV/c for minimum bias and 0%–40% most-central events, respectively. The rapidity density, dN/dy, of photons demonstrates the same power law as a function of dNch/dη observed in Au+Au at the same collision energy.

Trvalý link: http://hdl.handle.net/11104/0293758