Pion and Proton "Temperatures" in Relativistic Heavy-Ion Reactions
Abstract
Pion and proton production are measured to investigate thermal equilibrium in central collisions of 40Ar+KCl at 1.8 GeV/nucleon. The bulk of the pion yield is isotropic in the c.m. system, with an apparent temperature of 58+/-3 MeV, much lower than the 118+/-2 MeV of the protons. It is shown that the low pion "temperature" can be explained by the decay kinematics of delta resonances in thermal equilibrium. A (5+/-1)% component in the pion spectrum is, however, found to have a temperature of 110+/-10 MeV. The effect on the spectra of possible contributions from collective radial flow is discussed.
- Publication:
-
Physical Review Letters
- Pub Date:
- November 1984
- DOI:
- 10.1103/PhysRevLett.53.2012
- Bibcode:
- 1984PhRvL..53.2012B
- Keywords:
-
- 25.70.Np