Origin of the even-odd effect in the yields from high-energy reactions

The analysis of experimental production cross-sections of the light products of several nuclear reactions at high energy, measured at the FRS, GSI Darmstadt, revealed a very strong and complex even-odd staggering. The origin of this effect is related to the condensation process of heated nuclear matter while cooling down in the last evaporation step. The characteristics of the staggering correlate strongly with the lowest particle separation energy of the final experimentally observed nuclei. The study confirms the important role of the deexcitation process in fragmentation reactions, and indicates that sequential decay strongly influences the yields of light fragments, which are often used to extract information on the nature of nuclear reactions at high energies.