Nonlocal optical potential with core excitation in ${}^{10}\mathrm{Be}(d,p){}^{11}\mathrm{Be}$ and ${}^{11}\mathrm{Be}(p,d){}^{10}\mathrm{Be}$ reactions
We propose a new nonlocal form of the nucleon-nucleus optical potential and demonstrate its reliability. We extend the nonlocal potential to include the excitation of the nuclear core and develop energy-independent roton-${}^{10}\mathrm{Be}$ potential reasonably reproducing the experimental data at low energies. We apply the new potential to the study of deuteron stripping and pickup reactions ${}^{10}\mathrm{Be}(d,p){}^{11}\mathrm{Be}$ and ${}^{11}\mathrm{Be}(p,d){}^{10}\mathrm{Be}$ using rigorous three-body Faddeev-type equations for transition operators that are solved in the momentum-space partial-wave framework. The achieved description of the experimental data is considerably more successful as compared to previous studies with local potentials. The values of spectroscopic factors consistent with the data are determined, exhibiting only weak energy dependence. The results possibly indicate an increased predicting power of the proposed calculational scheme.
We apply the Lagrange-mesh $R$-matrix method to calculate the $S$-factor for the $^{13}$C$(p,γ)^{14}$N and $^{16}$O$(p,γ)^{17}$F direct radiative capture reactions. By comparing the astrophysical $S$-factors calculated with nonlocal and local potentials, we investigate the nonlocality effects coming from the nuclear potentials in the direct capture reactions. Our calculations are in good agreement with the experimental data and indicate a nonnegligible difference in the results of local and nonlocal potentials. The use of small diffuseness narrow potentials also provides a remarkably good fit …
Calculations of the direct radiative capture reactions are made for the $^{48}$Ca$(n,γ)^{49}$Ca, $^7$Li$(n,γ)^8$Li and $^{12}$C$(p,γ)^{13}$N reactions with the Perey-Buck type nonlocal potentials using a potential model. Our results reproduce the experimental data reasonably well. From comparisons with results obtained by using local potentials, it is found that the cross sections of direct capture reactions may change by around 25\% due to the nonlcality of nuclear potentials.
Theoretical models of the (d,p) reaction are exploited for both nuclear astrophysics and spectroscopic studies in nuclear physics. Usually, these reaction models use local optical model potentials to describe the nucleon- and deuteron-target interactions. Within such a framework the importance of the deuteron D-state in low-energy reactions is normally associated with spin observables and tensor polarization effects - with very minimal influence on differential cross sections. In contrast, recent work that includes the inherent nonlocality of the nucleon optical model potentials in the Johnson…
Angular-momentum or parity-dependent nonlocal optical potentials for nucleon-${}^{16}\mathrm{O}$ scattering able to fit differential cross section data over the whole angular regime are developed and applied to the description of deuteron-${}^{16}\mathrm{O}$ scattering in the framework of three-body Faddeev-type equations for transition operators. Differential cross sections and deuteron analyzing powers for elastic scattering and ${}^{16}\mathrm{O}(d,p){}^{17}\mathrm{O}$ transfer reactions are calculated using a number of local and nonlocal optical potentials and compared with experimental da…
We present a suite of codes (NLAT for nonlocal adiabatic transfer) to calculate the transfer cross section for single-nucleon transfer reactions, $(d,N)$ or $(N,d)$, including nonlocal nucleon-target interactions, within the adiabatic distorted wave approximation. For this purpose, we implement an iterative method for solving the second order nonlocal differential equation, for both scattering and bound states. The final observables that can be obtained with NLAT are differential angular distributions for the cross sections of $A(d,N)B$ or $B(N,d)A$. Details on the implementation of the T-matr…
We solved the nonlocal scattering and bound state equations using the Perey-Buck type interaction, and compared to local equivalent calculations. Using the distorted wave Born approximation we construct the T-matrix for (p,d) transfer on 17O, 41Ca, 49Ca, 127Sn, 133Sn, and 209Pb at 20 and 50 MeV. Additionally we studied (p,d) reactions on 40Ca using the the nonlocal dispersive optical model. We have also included nonlocality consistently into the adiabatic distorted wave approximation and have investigated the effects of nonlocality on on (d,p) transfer reactions for deuterons impinged on 16O, …
Nucleon transfer reactions in deuteron-deuteron collisions at energies above the three- and four-body breakup threshold are described using exact four-body equations for transition operators that are solved in the momentum-space framework. Differential cross sections, analyzing powers, polarizations, and spin transfer coefficients are obtained using realistic two-nucleon potentials and including the Coulomb repulsion between protons. Overall good agreement between predictions and experimental data is found. Most remarkable discrepancies are seen around the minima of the differential cross sect…
Background: Traditionally, nucleon-nucleus optical potentials are made local for convenience. In recent work we studied the effects of including nonlocal interactions explicitly in the final state for (d,p) reactions, within the distorted wave Born approximation. Purpose: Our goal in this work is to develop an improved formalism for nonlocal interactions that includes deuteron breakup and to use it to study the effects of including nonlocal interactions in transfer (d,p) reactions, in both the deuteron and the proton channel. Method: We extend the finite-range adiabatic distorted wave approxim…
${}^{20}\mathrm{O}(d,p){}^{21}\mathrm{O}$ transfer reactions are described using momentum-space Faddeev-type equations for transition operators and including the vibrational excitation of the ${}^{20}\mathrm{O}$ core. The available experimental cross section data at 10.5 MeV/nucleon beam energy for the ${}^{21}\mathrm{O}$ ground state $\frac52^+$ and excited state $\frac12^+$ are quite well reproduced by our calculations including the core excitation. Its effect can be roughly simulated reducing the single-particle cross section by the corresponding spectroscopic factor. Consequently, the extr…
The nonlocal dispersive optical model (NLDOM) nucleon potentials are used for the first time in the adiabatic analysis of a (d,p) reaction to generate distorted waves both in the entrance and exit channels. These potentials were designed and fitted by Mahzoon $et \text{ } al.$ [Phys. Rev. Lett. 112, 162502 (2014)] to constrain relevant single-particle physics in a consistent way by imposing the fundamental properties, such as nonlocality, energy-dependence and dispersive relations, that follow from the complex nature of nuclei. However, the NLDOM prediction for the $^{40}$Ca(d,p)$^{41}$Ca cros…
Adiabatic distorted-wave approximation (ADWA) study of three-body $(d,p)$ transfer reactions [G.W. Bailey, N.K. Timofeyuk, and J.A. Tostevin, Phys. Rev. Lett. 117, 162502 (2016)] reported strong sensitivity of cross sections to the neutron-proton $(np)$ interaction model when the nucleon-nucleus optical potential is nonlocal. The verification of this unusual finding using more reliable methods is aimed for in the present work. A rigorous Faddeev-type three-body scattering theory is applied to the study of $(d,p)$ transfer reactions. The equations for transition operators are solved in the mome…
The Perey-effect in two-body channels of $(d,p)$ reactions has been known for a long time. It arises when the nonlocal two-body deuteron-target and/or proton-target problem is approximated by a local one, manifesting itself in a reduction of the scattering channel wave functions in the nuclear interior. However, the $(d,p)$ reaction mechanism requires explicit accounting for three-body dynamics involving the target and the neutron and proton in the deuteron. Treating nonlocality of the nucleon-target interactions within a three-body context requires significant effort and demands going beyond …
Description of multinucleon transfer mechanism for ${}^{48} \mathrm{Ca}+{ }^{244} \mathrm{Pu}$ and ${ }^{86} \mathrm{Kr}+{}^{198} \mathrm{Pt}$ reactions in quantal transport approach
We explore the properties of the last generation of $ρ$(770) and $K^*$(892) resonances created in Au+Au reactions at E$_\mathrm{lab}=1.23$~AGeV via the reconstruction in the hadronic channel using the UrQMD model. Such resonance studies allow to obtain detailed information on the emission source in such reactions in a complementary way to di-lepton or HBT studies. We observe a freeze-out hierarchy and predict mass shifts for the $ρ$(770) resonance ($Δm_ρ\approx -330$ MeV) and the $K^*$(892) resonance ($Δm_{K^*} \approx -30$ MeV). These mass shifts are related to the regeneration cycles of each…
Multi-Model Analysis of the Astrophysical $S(E)$ Factor for the $^{9}\mathrm{Be}(p,α)^{6}\mathrm{Li}$ Reaction and Its Impact on Astrophysical Reaction Rates
School of Physics, Anhui University（安徽大学物理学院）；School of Physics, Southern University of Science and Technology（南方科技大学物理学院）；College of Physics and Optoelectronic Engineering, Shenzhen University（深圳大学物理与光电工程学院）；Institute of Radiation Technology, Beijing Academy of Science and Technology（北京市科学技术研究院辐射技术研究所）；Department of Nuclear Physics, China Institute of Atomic Energy（中国原子能科学研究院核物理系）
Bayesian analysis of the radiative capture reactions $^3\mathrm{He}(α,γ)^7\mathrm{Be}$ and $^3\mathrm{H}(α,γ)^7\mathrm{Li}$ are performed to draw inferences about the cross sections at threshold. We do a model comparison of two competing effective field theory power countings for the capture reactions. The two power countings differ in the contribution of two-body electromagnetic currents. In one power counting, two-body currents contribute at leading order, and in the other they contribute at higher orders. The former is favored for $^3\mathrm{He}(α,γ)^7\mathrm{Be}$ if elastic scattering data…
A review of recent applications of the nonlocal dispersive optical model (DOM) is presented that allows a simultaneous description of nuclear structure and nuclear reactions. An assessment of the quality of the resulting potentials for $^{40}$Ca and $^{48}$Ca is discussed for the description of the $(e,e'p)$ reaction to valence hole states and the possibility of interpreting the data in terms of absolute spectroscopic factors. The relevance of these results in the context of conflicting interpretations between transfer and knockout reactions is pointed out as well as the importance of proton r…
A review of the recent applications of the dispersive optical model (DOM) is presented. Emphasis is on the nonlocal implementation of the DOM that is capable of describing ground-state properties accurately when data like the nuclear charge density are available. The DOM, conceived by Claude Mahaux, provides a unified description of both elastic nucleon scattering and structure information related to single-particle properties below the Fermi energy. We have recently introduced a nonlocal dispersive optical potential for both the real and imaginary part. Nonlocal absorptive potentials yield eq…
We provide a microscopic description of the fusion reactions between $^{40,48}$Ca and $^{78}$Ni. The internuclear potentials are obtained using the density-constrained (DC) time-dependent Hartree-Fock (TDHF) approach and fusion cross sections are calculated via the incoming wave boundary condition method. By performing DC-TDHF calculations at several selected incident energies, the internuclear potentials for both systems are obtained and the energy-dependence of fusion barrier are revealed. The influence of tensor force on internuclear potentials of $^{48}\mathrm{Ca}+{}^{78}\mathrm{Ni}$ is mo…
We investigate theoretically the $K^{0} p$ invariant mass spectrum of the $K^{+} d \to K^{0} p p$ reaction and scrutinize how the signal of the "$Θ^{+}$" pentaquark, if it exists, emerges in the $K^{0} p$ spectrum. The most prominent advantage of this reaction is that we can clearly judge whether the "$Θ^{+}$" exists or not as a direct-formation production without significant backgrounds, in contrast to other reactions such as photoproduction and $π$-induced productions. We show that while the impulse or single-step scattering process can cover the "$Θ^{+}$" energy region with an initial kaon …
We investigate the QCD topological susceptibility $χ_t$ by using the nonlocal chiral quark model (NL$χ$QM). This model is based on the liquid instanton QCD-vacuum configuration in which $\mathrm{SU}(3)$ flavor symmetry is explicitly broken by the current quark mass $(m_{u,d},m_s)\approx(5,135)$ MeV. To compute $χ_t$, the local topological charge density operator $Q_t(x)$ is derived from the effective partition function of NL$χ$QM. We take into account the contributions from the leading-order (LO) ones $\sim\mathcal{O}(N_c)$ in the $1/N_c$ expansion. We also verify that the analytical expressio…
In present work, we investigated $K^{-}+\, ^{3}\mathrm{He}$ reaction at low energies. The coupled-channel Faddeev AGS equations were solved for $\bar{K}Nd-πΣ{d}$ three-body system in momentum representation to extract the scattering amplitudes. To trace the signature of the $Λ$(1405) resonance in the $πΣ$ invariant mass, the deuteron energy spectrum for $K^{-}+\,^{3}\mathrm{He}\rightarrowπΣ{d}$ reaction was obtained. Different types of $\bar{K}N-πΣ$ potentials based on phenomenological and chiral SU(3) approaches were used. As a remarkable result of this investigation, it was found that the de…
Self-Consistent Determination of the Transition Temperature Between the $^{14}\mathrm{C}(n,γ)^{15}\mathrm{C}$ and $^{14}\mathrm{C}(p,γ)^{15}\mathrm{N}$ Reactions
New York City College of Technology, The City University of New York（纽约市立学院，纽约市立大学）；The Graduate School and University Center, The City University of New York（研究生院与大学中心，纽约市立大学）；Long Island University（长岛大学）；al-Farabi Kazakh National University（阿里-法拉比哈萨克国立大学）；META University（META大学）
Recently, we have determined surface distributions of $α$ clusters in the ground state of $^{20}\mathrm{Ne}$ from $α$-transfer cross sections, without investigating the properties of its excited states. In this paper we extend our comprehension of $α$-cluster structures in excited states of nuclei through reaction studies. In particular we focus on $^{16}\mathrm{O}$, for which attention has been paid to advances of structure theory and assignment regarding $4^+$-resonance states. We study the surface manifestation of the $α$-cluster states in both the ground and excited states of $^{16}\mathrm…
Single-neutron transfer reactions populating states in the continuum are interesting both for structure and astrophysics. In their description often global optical potentials are used for the nucleon-target interactions, and these interactions are typically local. In our work, we study the effects of nonlocality in $(d,p)$ reactions populating continuum states. This work is similar to that of [1] but now for transfer to the continuum. A theory for computing cross sections for inclusive processes $A (d,p) X$ was explored in [2]. Therein, local optical potentials were used to describe the nucleo…
Charge-Exchange Reactions Accompanied by a Single $π^+$ Production in Medium-Energy Heavy-Ion Collisions
Frontiers Science Center for Rare Isotopes, Lanzhou University（兰州大学稀有同位素前沿科学中心）；School of Nuclear Science and Technology, Lanzhou University（兰州大学核科学与技术学院）
