Direct photons in WA98

0185570 - UJF-V 20020080 NL eng J - Článek v odborném periodiku
Lebedev, A. - Aggarwal, M. M. - Agnihotri, A. - Ahammed, Z. - Angelis, A. L. S. - Antonenko, V. - Arefiev, V. - Hřivnáčová, Ivana - Kugler, Andrej - Petráček, Vojtěch - Rak, Jan - Šumbera, Michal
Direct photons in WA98.
Nuclear Physics. A. Roč. 698, - (2002), s. 135C-142C. ISSN 0375-9474. E-ISSN 1873-1554
Grant CEP: GA ČR GA202/95/0217
Klíčová slova: hadron production * phase-transition * S+A collisions * 200-GeV/C * spectra
Kód oboru RIV: BF - Elementární částice a fyzika vys. energií
Impakt faktor: 1.568, rok: 2002

A measurement of direct photon production in Pb-208+Pb-208 collisions at 158 A GeV has been carried out in the CERN WA98 experiment. Invariant yield of direct photons was extracted as a function of transverse momentum in the interval 0.5<P-T<3.3 GeV/c for peripheral,and O.5<P-T<4.0 GeV/c for central collisons. Direct photon yield was extracted on a statistical basis as the difference between the measured inclusive spectrum of photons, and the calculated spectrum of photons which result from all hadrons with significant radiative decay contributions. While no direct photon excess was observed for the peripheral event sample, a significant direct photon signal, compared to statistical and systemical errors, was seen in central collisions at P-T>1.5 GeV/c. The results constitutes the first observation of direct photons in ultrarelativistic heavy-ion collisions.
Trvalý link: http://hdl.handle.net/11104/0081960