NUKLEONIKA 2006, 51(Suppl. 3):s7-s10

CAN THERMAL MODEL EXPLAIN (ANTI)LAMBDA/(ANTI)p PUZZLE?

Larissa V. Bravina1,2, Mads S. Nilsson1, Konrad Tywoniuk1, Evgeny E. Zabrodin1,2

1 Department of Physics, University of Oslo, PB 1048 Blindern, N-0316 Oslo, Norway
2 Institute for Nuclear Physics, Moscow State University, RU-119899 Moscow, Russia


The abnormally high antilambda-to-antiproton ratio, which is close to 3.6 for central Au+Au collisions at 11.7 AGeV/c, was reported by the E917 Collaboration. Conventional thermal models and microscopic transport models generally predict that the ratio should be below unity. We show that this large value of the ratio can be reproduced within a two-source statistical model of an ideal hadron gas, which employs non-uniform distribution of net baryon charge and net strangeness within the reaction volume. The two sources are assumed to reach the chemical and thermal equilibrium separately and may have different temperatures, strangeness densities, etc. Other hadron yields and ratios measured for the reaction are reproduced quite well.