A detailed study of total, Coulomb and nuclear breakup cross sections dependence on the projectile ground-state binding energy $\varepsilon_b$ is presented, by considering the $^8$Li+$^{12}$C and $^8$Li+$^{208}$Pb breakup reactions. To this end, apart from the experimental one-neutron separation energy of $^8$Li nucleus ($\varepsilon_b=2.03$~MeV), lower values of $\varepsilon_b$ down to $\varepsilon_b=0.01$~MeV, are also being considered. It is shown that all breakup processes become peripheral as $\varepsilon_b\to 0.01$ MeV, which is understood as due to the well-known large spacial extension of ground-state wave functions associated to weakly-bound projectiles. The Coulomb breakup cross section is found to be more strongly dependent on $\varepsilon_b$ than the nuclear breakup cross section, such that the Coulomb breakup becomes more significant as $\varepsilon_b$ decreases, even in a naturally nuclear-dominated reaction. This is mainly due to the long-range nature of the Coulomb forces, leading to a direct dependence of the Coulomb breakup on the electromagnetic transition matrix. It is also highlighted the fact that the nuclear absorption plays a minor role for small binding when the breakup becomes more peripheral.
A new method for calculating the Coulomb breakup of unstable neutron-rich isotopes at high energies is presented. The calculations employ the eikonal approximation and use a new Coulomb dynamical polarization potential (CDPP), calculated by solving the Schrödinger equation for the entire motion of the exotic projectile as a two-body cluster structure using the adiabatic approximation and incorporating excitations to the continuum. Calculations for some exotic isotopes are compared with Coulomb dissociation cross section data and found to be in good agreement.
Breakup of $^{9}$Be on $^{209}$Bi above and near the Coulomb barrier as a molecular single-particle effect: its influence on complete fusion and scattering
用绝热双中心壳模型方法研究了轰击能量在库仑势垒之上和附近时，$^{9}$ Be弹丸在$^{209}$ Bi靶上的破碎。研究了$^{9}$ Be $% \to $ n $+2α$破碎通道对完全熔合、弹性和非弹性截面的影响。结果表明，在碰撞核到达库仑势垒之前不久，抛射体$^{9}$ Be的分裂可能是由于分子单粒子效应。
The Coulomb-nuclear interference is studied as a function of the projectile ground-state binding energy in the 8Li + 12C and 8Li + 208Pb breakup reactions, by considering an arbitrary range for the 8Li ground-state binding energies εb, varying from the experimental one 2.03 MeV down to 0.01 MeV. Regardless the target mass, we first show that the Coulomb breakup cross section is stronger dependent on εb than the nuclear breakup cross section, due to the long-range nature of the Coulomb forces and to the electromagnetic transition matrix elements. For example, in case of 8Li + 208Pb reaction at …
Three-body Coulomb breakup of 11Li in the complex scaling method
用复标度法研究了~（11）Li到~（9 Li +n+n）三体系统的库仑破碎强度。我们将跃迁强度分解为三体共振、两体"10 Li + n“和三体" 9 Li +n+ n”连续态的贡献。在计算结果中，我们没有发现11 Li中具有尖锐衰减宽度的偶极共振。两体和三体连续态都产生了低能量的破碎强度增强。三体连续态的增强与11 Li的晕结构有很强的联系。计算的破碎强度分布与MSU，RIKEN和GSI的实验数据进行了比较。
The Coulomb-breakup method to extract the cross section for neutron radiative capture at astrophysical energies is analyzed in detail. In particular, its sensitivity to the description of the neutron-core continuum is ascertained. We consider the case of 14C(n, $γ$)15C for which both the radiative capture at low energy and the Coulomb breakup of 15C into 14C+n on Pb at 68 MeV/nucleon have been measured with accuracy. We confirm the direct proportionality of the cross section for both reactions to the square of the asymptotic normalization constant of 15C observed by Summers and Nunes [Phys. Re…
Coulomb Breakup Reactions in Complex-Scaled Solutions of the Lippmann-Schwinger Equation
本文提出了一种描述核三体破裂的新方法，该方法结合复标度法求解Lippmann-Schwinger方程。Lippmann-Schwinger方程（CSLS）的复尺度解使我们能够正确地处理多体明渠的边界条件，并从基态描述多体破裂振幅。用CSLS方法计算了从6 He基态到4 He +n+n三体衰变态的库仑破碎截面随总激发能的变化，计算结果与实验数据吻合较好.此外，还得到了E1跃迁强度的二维能量分布，证实了5 He（3/2-）共振的重要性。结果表明，CSLS是研究弱束缚核三体破裂反应中各子系统关联的一种很有前途的方法。
Breakup cross sections are determined for the Borromean nucleus 22C by using a four-body eikonal model, including Coulomb corrections. Bound and continuum states are constructed within a 20C + n + n three-body model in hyperspherical coordinates. We compute continuum states with the correct asymptotic behavior through the R-matrix method. For the n+ n potential, we use the Minnesota interaction. As there is no precise experimental information on 21C, we define different parameter sets for the 20C + n potentials. These parameter sets provide different scattering lengths, and resonance energies …
Simultaneous Optical Model Analyses of Elastic Scattering, Breakup, and Fusion Cross Section Data for the $^{6}$He + $^{209}$Bi System at Near-Coulomb-Barrier Energies
Purpose : The aim of this paper is to study the elastic Coulomb breakup of $^{34}$Na on $^{208}$Pb to give us a core of $^{33}$Na with a neutron and in the process we try and investigate the one neutron separation energy and the ground state configuration of $^{34}$Na. Method : A fully quantum mechanical Coulomb breakup theory within the architecture of post-form finite range distorted wave Born approximation extended to include the effects of deformation is used to research the elastic Coulomb breakup of $^{34}$Na on $^{208}$Pb at 100 MeV/u. The triple differential cross-section calculated fo…
The incomplete fusion dynamics of $^6$Li + $^{209}$Bi collisions at energies above the Coulomb barrier is investigated. The classical dynamical model implemented in the {\sc platypus} code is used to understand and quantify the impact of both $^6$Li resonance states and transfer-triggered breakup modes (involving short-lived projectile-like nuclei such as $^8$Be and $^5$Li) on the formation of incomplete fusion products. Model calculations explain the experimental incomplete-fusion excitation function fairly well, indicating that (i) delayed direct breakup of $^6$Li reduces the incomplete fusi…
We use a three-body Continuum Discretized Coupled Channel (CDCC) model to investigate Coulomb and nuclear effects in breakup and reaction cross sections. The breakup of the projectile is simulated by a finite number of square integrable wave functions. First we show that the scattering matrices can be split in a nuclear term, and in a Coulomb term. This decomposition is based on the Lippmann-Schwinger equation, and requires the scattering wave functions. We present two different methods to separate both effects. Then, we apply this separation to breakup and reaction cross sections of 7Li + 208…
