Abstract:
In this article, the incident energy dependence of transverse flow from the collisions of
^64\rmZn +
^58\rmNi near the Fermi energy is investigated experimentally based on a two-particle azimuthal correlation(2pAC) approach. The transverse flow values from the mid-peripheral collisions at the incident energies of 26, 35 and 47 MeV/u are extracted using the 2pAC approaches with and without the specific consideration of the recoil effect from the emitted particle of interest to the residue in an event-by-event basis, respectively. The flow values extracted from both approaches show consistently increasing trend as a function of incident energy. In contrast, the flow values for the three energies show different in magnitude, that those from the improved 2pAC approach with the consideration of the recoil effect are significantly reduced. The balance energy of the mid-peripheral
^64\rmZn +
^58\rmNi collisions is further investigated using linear fit for the obtained transverse flow versus incident energy, and two balance energy values are obtained to be
(110.1\pm5.8) MeV/u for the improved 2pAC approach and
(128.0\pm5.6) MeV/u for the original 2pAC approach, respectively. These two values are compared with those previously measured based on the conventional flow extraction approach involving the reaction plane reconstruction process. It is found that the balance energy from the improved 2pAC approach, rather than that from the original 2pAC approach, follows well the relation of balance energy versus impact parameter from the conventional approach. This comparison suggests the necessity for considering the recoil effect correction in the flow extraction using the 2pAC approach, and the equivalence between the improved 2pAC approach and the conventional flow extraction approach involving the reaction plane reconstruction process in the investigation on the balance energy.