Mass Dependence Of Light-Nucleus Production In Ultrarelativistic Heavy-Ion Collisions

Light nuclei can be produced in the central reaction zone via coalescence in relativistic heavy-ion collisions. Experiment 864 at BNL has measured the production of ten light nuclei with nuclear number A = 1 to A = 7 at rapidity y similar or equal to 1.9 and p(T)/A similar or equal to 300 MeV/c. Data were taken with a Au beam of momentum of 11.5A GeV/c on a Pb or Pt target with different experimental settings. The invariant yields show a striking exponential dependence on nuclear number with a penalty factor of about 50 per additional nucleon. Detailed analysis reveals that the production may depend on the spin factor of the nucleus and the nuclear binding energy as well.