Within our aim to clarify some aspects of the breakup dynamics of loosely-bound neutron-halo projectiles on a heavy target,we apply the continuum discretized coupled-channel formalism to investigate the beryllium^(11)...Within our aim to clarify some aspects of the breakup dynamics of loosely-bound neutron-halo projectiles on a heavy target,we apply the continuum discretized coupled-channel formalism to investigate the beryllium^(11)Be breakup on a lead^(208)Pb target atE_(lab)=140 MeV incident energy.By evidencing that the continuum–continuum couplings are much stronger in the nuclear breakup than in the Coulomb breakup,we conclude that the strength of these couplings in the total breakup is dominated by the nuclear contribution,with the diagonal monopole nuclear potential in the projectile–target center-of-mass having negligible effect on the total and nuclear breakup cross-sections.For this kind of reaction,we show that the condition for the total breakup to approach its dominant component in the absorption region is strongly dependent on the continuum–continuum couplings and the diagonal monopole nuclear potential.展开更多
An analysis of the breakup of the 31 Ne weakly-bound neutron-halo system on a lead target is presented,considering the 2p_(3/2) and 1f_(7/2) ground-state configurations.It is shown that a high centrifugal barrier almo...An analysis of the breakup of the 31 Ne weakly-bound neutron-halo system on a lead target is presented,considering the 2p_(3/2) and 1f_(7/2) ground-state configurations.It is shown that a high centrifugal barrier almost wipes out the breakup channel,thus assimilating the breakup of a weakly-bound system to that of a tightly-bound system,and also reduces the range of the monopole nuclear potential.Consequently,a high centrifugal barrier prevents the suppression of the Coulomb-nuclear interference(CNI) peak by weakening couplings to the breakup channel and reducing the range of the monopole nuclear potential,two main factors that would otherwise suppress such a peak.The present study also identifies couplings to the breakup channel and a long-ranged monopole nuclear potential as the main factors that lead to the suppression of the CNI peak.A low centrifugal barrier together with a Coulomb barrier would also effectively prevent the suppression of the CNI peak in proton-halos as reported in the case of the 8B proton-halo.展开更多
Proton-halo breakup behavior in theε0→0 limit(whereε0 is the ground-state binding energy)is stud-ied around the Coulomb barrier in the^(8)B+^(58)Ni reaction for the first time.For practical purposes,apart from the ...Proton-halo breakup behavior in theε0→0 limit(whereε0 is the ground-state binding energy)is stud-ied around the Coulomb barrier in the^(8)B+^(58)Ni reaction for the first time.For practical purposes,apart from the ex-perimental 8B binding energy of 137 keV,three more arbitrarily chosen values(1,0.1,0.01 keV)are considered.It is first shown that the Coulomb barrier between the core and the proton prevents the^(7)Be+p system from reaching the state of an open proton-halo system,w hich,among other factors,would require the ground-state wave function to extend to infinity in the asymptotic region,asε0→0.The elastic scattering cross section,which depends on the density of the ground-state wave function,is found to have a negligible dependence on the binding energy in this limit.The total,Coulomb and nuclear breakup cross sections are all reported to increase significantly fromε0=137 to 1.0 keV,and converge to their maximum values asε0→0.This increase is mainly understood as coming from a longer tail of the ground-state wave function forε0≤1.0 keV,compared to that forε0=137 keV.It is also found that the effect of the continuum-continuum couplings is to slightly delay the convergence of the breakup cross section.The analysis of the reaction cross section indicates a convergence of all the breakup observables asε0→0.These results provide a better sense of the dependence of the breakup process on the breakup threshold.展开更多
基金LT acknowledge support from Conselho Nacional de Desenvolvimento Científico e Tecnológico[Procs.304469-2019-0 and 464898/2014-5(INCT-FNA)]Fundação de AmparoàPesquisa do Estado de São Paulo[Projs.2017/05660-0]。
文摘Within our aim to clarify some aspects of the breakup dynamics of loosely-bound neutron-halo projectiles on a heavy target,we apply the continuum discretized coupled-channel formalism to investigate the beryllium^(11)Be breakup on a lead^(208)Pb target atE_(lab)=140 MeV incident energy.By evidencing that the continuum–continuum couplings are much stronger in the nuclear breakup than in the Coulomb breakup,we conclude that the strength of these couplings in the total breakup is dominated by the nuclear contribution,with the diagonal monopole nuclear potential in the projectile–target center-of-mass having negligible effect on the total and nuclear breakup cross-sections.For this kind of reaction,we show that the condition for the total breakup to approach its dominant component in the absorption region is strongly dependent on the continuum–continuum couplings and the diagonal monopole nuclear potential.
文摘An analysis of the breakup of the 31 Ne weakly-bound neutron-halo system on a lead target is presented,considering the 2p_(3/2) and 1f_(7/2) ground-state configurations.It is shown that a high centrifugal barrier almost wipes out the breakup channel,thus assimilating the breakup of a weakly-bound system to that of a tightly-bound system,and also reduces the range of the monopole nuclear potential.Consequently,a high centrifugal barrier prevents the suppression of the Coulomb-nuclear interference(CNI) peak by weakening couplings to the breakup channel and reducing the range of the monopole nuclear potential,two main factors that would otherwise suppress such a peak.The present study also identifies couplings to the breakup channel and a long-ranged monopole nuclear potential as the main factors that lead to the suppression of the CNI peak.A low centrifugal barrier together with a Coulomb barrier would also effectively prevent the suppression of the CNI peak in proton-halos as reported in the case of the 8B proton-halo.
文摘Proton-halo breakup behavior in theε0→0 limit(whereε0 is the ground-state binding energy)is stud-ied around the Coulomb barrier in the^(8)B+^(58)Ni reaction for the first time.For practical purposes,apart from the ex-perimental 8B binding energy of 137 keV,three more arbitrarily chosen values(1,0.1,0.01 keV)are considered.It is first shown that the Coulomb barrier between the core and the proton prevents the^(7)Be+p system from reaching the state of an open proton-halo system,w hich,among other factors,would require the ground-state wave function to extend to infinity in the asymptotic region,asε0→0.The elastic scattering cross section,which depends on the density of the ground-state wave function,is found to have a negligible dependence on the binding energy in this limit.The total,Coulomb and nuclear breakup cross sections are all reported to increase significantly fromε0=137 to 1.0 keV,and converge to their maximum values asε0→0.This increase is mainly understood as coming from a longer tail of the ground-state wave function forε0≤1.0 keV,compared to that forε0=137 keV.It is also found that the effect of the continuum-continuum couplings is to slightly delay the convergence of the breakup cross section.The analysis of the reaction cross section indicates a convergence of all the breakup observables asε0→0.These results provide a better sense of the dependence of the breakup process on the breakup threshold.
