NandZodd-even staggering in Kr+Sn collisions at Fermi energies

Abstract

The odd-even staggering of the yield of final reaction products has been studied as a function of proton (Z) and neutron (N ) numbers for the collisions 84 Kr+ 112 Sn and 84 Kr+ 124 Sn at 35 MeV/nucleon, in a wide range of elements (up to Z ≈ 20). The experimental data show that staggering effects rapidly decrease with increasing size of the fragments. Moreover the staggering in N is definitely larger than the one in Z. Similar general features are qualitatively reproduced by the GEMINI code. Concerning the comparison of the two systems, the staggering in N is in general rather similar, being slightly larger only for the lightest fragments produced in the n-rich system. In contrast the staggering in Z, although smaller than that in N , is sizably larger for the n-poor system with respect to the n-rich one.

Influence of the density of states on the odd-even staggering in the charge distribution of the emitted fragments in nuclear heavy-ion collisions

“…[20] shows that important odd-even effects are observed for fragments with Z < 15 and, in the case of peripheral collisions, they can be observed up to Z = 40. On the other hand, other experimental results [22] reveal that these effects rapidly decrease as the fragment size increases.…”

“…(22) in the staggering properties of the charge distribution. In this way, the primary and final charge distributions for the fragmentation of the 40 Ca nucleus, at a few excitation energies, are displayed in Fig.…”

“…The larger pairing energy clearly leads to more important odd-even effects and, therefore, the analyses made in Refs. [18][19][20][21][22] may be helpful in finding the best parameterization for the pairing term, but this requires a careful treatment of the deexcitation of the primary fragments in order to minimize ambiguities.…”

“…Odd-even effects on the fragment charge distributions produced in different reactions have been recently reported in the literature [18][19][20][21][22]. Analyses based on the fragmentation of the quasi-projectile have been made at relativistic energies [18] as well as at much lower bombarding energies [21].…”

Influence of angular momentum and Coulomb interaction of colliding nuclei on their multifragmentation

“…Both trends can easily be explained within the statistical framework [5,12,33] because of the enhanced disintegration of nuclei at high excitations into more neutron-rich IMF, while a dynamical calculation predicts more neutron-rich IMF in very peripheral colli-sions since the neutron-rich periphery of nuclei influences the dynamics of IMF formation [38]. We believe that the presented generalization of the statistical approach is very useful for the analysis of coming novel experiments aimed predominantly at measuring isotopes at low and intermediate energy collisions [25,43]. As it was extensively discussed in Ref.…”