Extension of the ratio method to proton-rich nuclei

Abstract

Background: The ratio method has been developed to improve the study of one-neutron halo nuclei through reactions. By taking the ratio of angular distributions for two processes, viz. breakup and elastic scattering, this new observable is nearly independent of the reaction mechanism and hence much more sensitive to the projectile structure than the cross sections for each single process.Purpose: We study the extension of the ratio method to proton-rich nuclei. We also explore the optimum experimental conditions for measuring this new observable. Method:We compare accurate dynamical calculations of reactions for proton-rich projectiles to the prediction of the ratio method. We use the dynamical eikonal approximation that provides good results for this kind of reactions at intermediate energy.Results: Our tests for 8 B, an archetypical one-proton halo nucleus, on Pb, Ni, and C targets at 44 MeV/nucleon show that the method can be extended to proton-rich nuclei. The sensitivity of the ratio observable to the singleparticle structure of the projectile is studied in detail. The method is not affected if energy ranges-or bins-are considered in the projectile continuum. This makes the ratio easier to measure experimentally by increasing the breakup cross section. Light elements provide the optimal targets to exploit this observable in practice. We also extend our analysis to 17 F, 25 Al, and 27 P, whose study is of interest to both nuclear astrophysics and nuclear structure.Conclusions: We show that, albeit less precise than for one-neutron halo nuclei, the ratio method can be extended to proton-rich nuclei and that it provides valuable information about their structure. It is especially accurate for nuclei with a valence proton loosely bound in an s or p orbital, i.e. for one-proton halo nuclei.

Study of cluster structures in nuclei through the ratio method

“…The encouraging results gathered in that analysis lead to the idea that the method might be extended outside the range of validity of the REB, viz. for low-energy reactions [34] and to one-proton halo nuclei [35]. In the following sections, we summarise these different studies and present their major outcomes.…”

“…for collision at lower beam energy [34] (see Sect. 4) and to one-proton halo nuclei [35] (see Sect. 5).…”

“…6 Extension of the ratio method to proton halos. The collision of 8 B at 44 MeV/nucleon on (a) 12 C and (b) 208 Pb have been calculated with the DEA [35,38]. The solid black lines show the results of fully dynamical calculations, while the dashed lines correspond to calculations without the p-T interaction.…”

“…Results using a different V cT are shown using dash-dotted lines. The REB prediction F E,0 ( Q 2 for the ratio (16) in MeV −1 is shown by the thick gray line [35]. The summed cross section ( 17) is displayed as a ratio to Rutherford while the breakup angular distribution is in b/MeV sr. ©IOP Publishing.…”

“…4 and 5 the extension of this idea beyond the range of validity of the REB, viz. to low-energy collisions [34] and proton-halo nuclei [35], respectively. In Sect.…”