Isobaric yield ratio difference and neutron density difference in calcium isotopes

Abstract

The isobaric yield ratio difference between two reactions is found to equal μ 21 /T , which denotes the ratio of the difference between the neutron and proton chemical potentials to the temperature. A series of projectile fragmentation reactions induced by calcium isotopes are calculated using a modified statistical abrasion-ablation model, assuming the neutron density distribution to be the Fermi type. The μ 21 /T from the prefragments are found to be sensitive to the difference between the neutron density distributions of projectiles, while μ 21 /T from the final fragments are very similar for the reactions and insensitive to the difference between the neutron density distributions of projectiles. The μ 21 /T from the prefragments and final fragments verify that the deexcitation modifies the results largely.

Isobaric yield ratio difference between the140AMeVNi58+BeQiao1, Wei2, Ma3 et al. 2015Phys. Rev. CSelf Cite12070View full textAdd to dashboardCite

“…Considering two reactions where the measurement situations are the same (where the temperature of the reactions can be assumed as the same), the IYR difference between the reactions, i.e., IBD, is defined as [3][4][5][6],…”

“…In a typical IBD distribution, there is a plateau part plus a changing (increasing or decreasing) part as the function of the mass numbers A of fragments [3][4][5][6]. The plateau part is explained as denoting the region where the chemical potential (or the density) difference of neutrons and protons changes very little.…”

“…The plateau part is explained as denoting the region where the chemical potential (or the density) difference of neutrons and protons changes very little. The modified statistical abrasion-ablation (SAA) model [25] was used to * Email: machunwang@126.com study the IBD and the nuclear density difference of neutrons and protons between the calcium-isotope-induced reactions [5,6], which suggests that the IBD is sensitive to the nuclear density extracted from the prefragments, but the sensitivity is weakened in the results for the final fragments. Because the SAA calculation cannot reproduce some of the IYR distributions, the IBD results by SAA cannot well explain the measured data [5].…”

“…The modified statistical abrasion-ablation (SAA) model [25] was used to * Email: machunwang@126.com study the IBD and the nuclear density difference of neutrons and protons between the calcium-isotope-induced reactions [5,6], which suggests that the IBD is sensitive to the nuclear density extracted from the prefragments, but the sensitivity is weakened in the results for the final fragments. Because the SAA calculation cannot reproduce some of the IYR distributions, the IBD results by SAA cannot well explain the measured data [5]. The SAA model has a simple collision and deexcitation mechanism [26,27], which does not include the system evolution.…”

“…The isobaric yield ratio difference (IBD) method, which is similar to the isoscaling method [1,2], has been developed to study chemical potentials of neutrons and protons [3,4] or the nuclear density [5][6][7] in heavy-ion collisions. Based on the isobaric yield ratio (IYR), the IBD method provides cancellation of both the system dependence parameters [8][9][10][11], the free energies of isobars [3], and the terms contributing to the free energy of fragments [8,[12][13][14][15][16] in the formula determining the cross sections of fragment.…”