Electric dipole response of low-lying excitations in the two-neutron halo nucleus F29
Electric dipole response of low-lying excitations in the two-neutron halo nucleus F29
复制标题
双中子晕核F29低位激发的电偶极子响应
DOI：
10.1103/physrevc.102.064627
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发表时间：
2020
影响因子：
3.1
通讯作者：
Vitturi A.
中科院分区：
文献类型：
--
作者：
Casal J.;Singh Jagjit;Fortunato L.;Horiuchi W.;Vitturi A.
背景：最近通过击穿和相互作用截面测量对富中子同位素进行了研究。在超球谐展开式中建立了波函数，并用Glauber理论计算了总反应截面，讨论了低激发的电偶极响应和偶极耦合对核反应的影响。用解析变换谐振子基用赝态方法描述了连续态和跃迁几率。在连续介质离散耦合通道(CDCC)计算中使用了相应的结构形状因子来描述低能散射。结果：宇称反转导致搁浅状态，其特征是57.5%的中间组分，强烈的双中子组态，以及物质半径相对于核心半径的增加。Glauber模型对240 MeV/核子的碳靶的计算提供了1370mb的总反应截面，与最近的数据一致。该模型还产生了与四极激发相对应的勉强束缚激发态。对连续谱的计算给出了高达6 MeV的总强度为1.59，并且分布在MeV处呈现共振。结果采用标准壳模型排序，大大减少了分布。库仑势垒附近的四体CDCC计算以偶极耦合为主，完全抵消了弹性散射截面上的菲涅耳峰。结论：利用最新的实验信息，我们对库仑势垒周围的三体计算与双中子晕是一致的。我们的预测显示了晕核预期的响应的微弱增强，以及重靶上低能反应的偶极耦合的关联性。这些发现可能会指导未来的实验活动。
Background:The neutron-richisotopes have been recently studied via knockout and interaction cross-section measurements. The two-neutron halo inhas been linked to the occupancy ofintruder configurations.Purpose:We investigate the bound spectrum and continuum states in, focusing on the electric dipoleresponse of low-lying excitations and the effect of dipole couplings on nuclear reactions.Method:wave functions are built within the hyperspherical harmonics expansion formalism, and total reaction cross sections are calculated using the Glauber theory. Continuum states andtransition probabilities are described in a pseudostate approach using the analytical transformed harmonic oscillator basis. The corresponding structure form factors are used in continuum-discretized coupled-channels (CDCC) calculations to describe low-energy scattering.Results:Parity inversion inleads to aground state characterized by 57.5% ofintruder components, a strong dineutron configuration, and an increase of the matter radius with respect to the core radius offm. Glauber-model calculations for a carbon target at 240 MeV/nucleon provide a total reaction cross section of 1370 mb, in agreement with recent data. The model produces also a barely bound excited state corresponding to a quadrupole excitation.calculations into the continuum yield a total strength of 1.59up to 6 MeV, and thedistribution exhibits a resonance atMeV. Results using a standard shell-model order forlead to a considerable reduction of thedistribution. The four-body CDCC calculations foraround the Coulomb barrier are dominated by dipole couplings, which totally cancel the Fresnel peak in the elastic-scattering cross section.Conclusions:Our three-body calculations for, using the most recent experimental information on, are consistent with a two-neutron halo. Our predictions show the low-lying enhancement of theresponse expected for halo nuclei and the relevance of dipole couplings for low-energy reactions on heavy targets. These findings may guide future experimental campaigns.