New approach of fragment charge correlations in 129 Xe + nat Sn central collisions

A recent analysis of the charge (Z) correlations in the ∆Z− < Z > plane for Xe+Sn central collisions at 32 MeV/n has shown an enhancement in the production of equally sized fragments (low ∆Z) which was interpreted as an evidence for spinodal decomposition. However the signal is weak and rises the question of the estimation of the uncorrelated yield. After a critical analysis of its robustness, we propose in this paper a new technique to build the uncorrelated yield in the charge correlation function. The application of this method to Xe+Sn central collision data at 32, 39, 45 and 50 MeV/n does not show any significant enhancement at low ∆Z.