Influence of secondary decay on odd-even staggering of fragment cross sections

Abstract

Odd-Even Staggering (OES) appears in many areas of nuclear physics, and is generally associated with the pairing term in the nuclear binding energy. To explore this effect, we use the Improved Statistical Multifragmentation Model to populate an ensemble of hot primary fragments, which are then de-excited using the Weisskopf-Ewing statistical emission formalism. The yields are then compared to experimental data. Our results show that, before secondary decay, OES appears only in the yields of even mass fragments and not in the yields of odd mass fragments. De-excitation of the hot fragments must be taken into account to describe the data, suggesting that the OES in fragment yields is a useful criterion for validating or adjusting theoretical de-excitation models.