Abstract
Pion and proton production are measured to investigate thermal equilibrium in central collisions of +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.
- Received 30 July 1984
DOI:https://doi.org/10.1103/PhysRevLett.53.2012
©1984 American Physical Society