Jin Lei

• PhD
• Professor at Tongji University

Collisions between complex nuclei may give rise to their total or partial fusion. The latter case is found experimentally to gain importance when one of the colliding nuclei is weakly bound. It has been commonly assumed that the partial fusion mechanism is a two-step process, whose first step is the dissociation of the weakly bound nucleus, followe...

We present the first example of a rigorous uncertainty quantification on elastic nucleus-nucleus scattering at energies near the Coulomb barrier. Experimental data has been analyzed using an energy-dependent effective optical model potential with physical constraints imposed. We confirm the compatibility of these uncertainties with the well known C...

Experimental studies of nuclear collisions involving light weakly bound nuclei show a systematic suppression of the complete fusion cross section by ∼30% with respect to the expectation for tightly bound nuclei, at energies above the Coulomb barrier. Although it is widely accepted that the phenomenon is related to the weak binding of these nuclei,...

Background: Large α yields have been reported over the years in reactions with Li6 and Li7 projectiles. Previous theoretical analyses have shown that the elastic breakup (EBU) mechanism (i.e., projectile breakup leaving the target in its ground state) is able to account only for a small fraction of the total α-inclusive breakup cross sections, poin...

The problem of the calculation of inclusive breakup cross sections in nuclear reactions is reexamined. For that purpose, the post-form theory proposed by Ichimura, Austern and Vincent [Phys. Rev. C32, 431 (1985) is revisited, and an alternative derivation of the non-elastic breakup part of the inclusive breakup is presented, making use of the coupl...

We address the problem of evaluating neutron-transfer induced breakup cross sections caused by the Borromean nucleus $^{9}$Be, using the reaction $^{197}$Au($^{9}$Be,$^{8}$Be)$^{198}$Au as a test case. This reaction was recently measured over a wide range of incident energies around the Coulomb barrier. To deal with the high density of $^{198}$Au s...

The Li8+Sn120 collision has been investigated at laboratory energies of 21.7 and 25.8 MeV (VCBlab=20.5 MeV). The Li8+Sn120 elastic scattering and the Li7 fragment angular and energy distributions from the Sn120(Li8,Li7)X reaction have been measured. The elastic scattering angular distributions were analyzed by optical model and coupled reaction cha...

We present a novel scattering emulator utilizing the complex scaling method to enhance nuclear reaction analysis. This approach leverages a single set of reduced bases, allowing for efficient and simultaneous emulation across multiple channels and potential parameters, significantly reducing computational storage and accelerating calculations. Demo...

This study explores the application of Kolmogorov-Arnold Networks (KANs) in predicting nuclear binding energies, leveraging their ability to decompose complex multi-parameter systems into simpler univariate functions. By utilizing data from the Atomic Mass Evaluation (AME2020) and incorporating features such as atomic number, neutron number, and sh...

We introduce COLOSS, a program designed to address the scattering problem using a bound-state technique known as complex scaling. In this method, the oscillatory boundary conditions of the wave function are transformed into exponentially decaying ones, accommodating the long-range Coulomb interaction. The program implements the Woods-Saxon form of...

We explore the impact of half-shell components on nuclear reaction calculations, focusing on nonelastic breakup cross sections within the Ichimura-Austern-Vincent (IAV) model. By advocating for the use of a consistent Single Folding Model (SFM) for all optical potentials in IAV calculations, we aim to reduce the uncertainties associated with half-s...

The angular distributions for the elastic scattering and breakup reactions of the mirror nuclei B12 and N12 on a Pb208 target, at incident energies of 255 MeV and 343 MeV, respectively, were measured at HIRFL-RIBLL. The elastic scattering and breakup angular distributions of the halolike nucleus N12 (Sp=0.601 MeV) have been measured simultaneously....

Elastic scattering angular distributions of $^{13}$C at 340 MeV and of $^{14}$C at 294 MeV and 342 MeV on a $^{208}$Pb target, which correspond to around five times the Coulomb barriers, were measured at the Radioactive Ion Beam Line in Lanzhou. The data were analyzed within the optical model and the continuum-discretized coupled-channels (CDCC) fr...

Inclusive breakup is an important reaction mechanism of reactions induced by weakly bound nuclei. The Ichimura, Austern, and Vincent (IAV) model is widely used to analyze inclusive breakup processes and is based on a distorted wave Born approximation (DWBA). However, the validity of the DWBA form for inclusive breakup requires further exploration....

The ⁸ B+ ⁶⁴ Zn reaction at 38.5 MeV has been studied at HIE-ISOLDE CERN to investigate proton halo effect on the reaction dynamics. For the first time it was used the only existing post-accelerated ⁸ B beam. The measured elastic scattering angular distribution showed a small suppression of the Coulomb-nuclear interference peak, opposite to what obs...

In the present research, we utilized the single-folding model to develop a systematical optical potential for Li6 and Li7, employing the nucleon-nucleus global potentials introduced by Koning and Delaroche (KD02). We analyzed the elastic scattering angular distributions of Li6 and Li7 on targets with mass numbers ranging from 24 to 209 using the si...

We examine the validity of surface approximation for breakup reactions using a fully quantum-mechanical model proposed by Ichimura, Austern, and Vincent (IAV). Analogous to the semiclassical picture, we introduce radial cut-offs to scattering waves in the IAV framework, which we refer to as IAV-cut. Systematic calculations are conducted for nonelas...

We confirm the validity of surface approximation for breakup reactions with a fully quantum-mechanical model proposed by Ichimura, Austern, and Vincent (IAV). Analogous to the semi-classical picture, we introduce radial cut-offs to scattering waves in the IAV framework, which we refer to as IAV-cut. Systematic calculations for $^6$Li and deuteron i...

This study focuses on the deuteron-induced inclusive breakup reaction and investigates the (d,pX) and (d,nX) channels for light and medium mass nuclei. To study the double differential cross section of nonelastic breakup, we employed the models of Ichimura, Austern, and Vincent (IAV) [Phys. Rev. C 32, 431 (1985)] and the Glauber model with the quan...

Inclusive breakup is an important reaction mechanism of reactions induced by weakly bound nuclei. The Ichimura, Austern, and Vincent (IAV) model is widely used to analyze inclusive breakup processes and is based on a Distorted Wave Born Approximation (DWBA). However, the validity of the DWBA form for inclusive breakup requires further exploration....

The \(^8\)Li + \(^9\)Be quasi-elastic angular distribution and the \(^{9}\)Be(\(^{8}\)Li\(,^{7}\)Li)X inclusive reaction have been measured at E\(_{\textrm{Lab}}=23.8\) MeV bombarding energy using the RIBRAS facility. In addition to the \(^8\)Li scattering peak, a large yield of \(^7\)Li particles has been observed in the identification spectra, pr...

We propose an extension of the inclusive breakup model of Ichimura, Austern and Vincent [Phys. Rev. C 32, 431 (1985)] for the evaluation of incomplete fusion (ICF) cross sections in nuclear reactions induced by two-body projectiles. The main idea, adopted in other methods, consists in the separation of the participant-target optical potential into...

DOI:https://doi.org/10.1103/PhysRevC.106.019901

Elastic scattering measurements were performed for the proton drip-line nucleus O13 (with Sp=1.512 MeV) and its partner mirror nucleus B13 (with Sn=4.878 MeV) projectiles on a Pb208 target at intermediate energies, namely Elab=413 and 254 MeV, respectively. These secondary radioactive ion beams were produced at the Radioactive Ion Beam Line in Lanz...

Quasielastic scattering and breakup angular distributions for the neutron halo nucleus Be11 on a Pb208 target at the laboratory energy of 210 MeV, which corresponds to 5.2 times the Coulomb barrier, were measured at HIRFL-RIBLL (Heavy-Ion Research Facility in Lanzhou and Radioactive Ion Beam Line in Lanzhou). The quasielastic scattering angular dis...

The Li8+Ni58 collision is investigated at 23.9, 26.1, 28.7, and 30 MeV bombarding energies. Quasielastic angular distributions and the singles Li7 angular and energy distributions are presented. Coupled-reaction channels (CRC) calculations, which include the coupling of the elastic channel to Ni59=Ni58+n states above and below the neutron threshold...

Proton halo effects in the ⁸B+⁶⁴Zn reaction at an energy around 1.5 times the Coulomb barrier have been studied at HIE-ISOLDE CERN using, for the first time, the only existing postaccelerated ⁸B beam. This, together with the use of a high granularity and large solid angle detection system, allowed for a careful mapping of the elastic angular distri...

Elastic scattering and breakup angular distributions of the weakly bound radioactive nucleus B8 on a Pb208 target at an incident energy of 238 MeV, which corresponds to four times the Coulomb barrier, have been measured at the HIRFL-RIBLL facility (Institute of Modern Physics, Lanzhou). The data have been analyzed using the optical model and the co...

The full quantum mechanical (QM) model of inclusive breakup of Ichimura-Austern-Vincent (IAV) is implemented in this paper to calculate breakup from heavy radioactive nuclei on a ⁹Be target at intermediate energies. So far it had been implemented and applied only to low energy reactions with light projectiles. The IAV model is successful in predict...

In 1985, Hussein and McVoy [Nuc. Phys. A445 (1985) 124] elucidated a formula for the evaluation of the nonelastic breakup (“stripping”) contribution in inclusive breakup reactions. The formula, based on the spectator core model, acquires a particularly simple and appealing form in the eikonal limit, to the extent that it has become the standard pro...

In 1985, Hussein and McVoy [Nuc. Phys. A445 (1985) 124] elucidated a formula for the evaluation of the nonelastic breakup ("stripping") contribution in inclusive breakup reactions. The formula, based on the spectator core model, acquires a particularly simple and appealing form in the eikonal limit, to the extent that it has become the standard pro...

The mechanism of reactions with weakly-bound proton-rich nuclei at energies near the Coulomb barrier is a long-standing open question owing to the paucity of experimental data. In this study, a complete kinematics measurement was performed for the proton drip-line nucleus 17F interacting with 58Ni at four energies near the Coulomb barrier. Thanks t...

The full quantum mechanical (QM) model of inclusive breakup of Ichimura-Austern-Vincent (IAV) is implemented in this paper to calculate breakup from heavy radioactive nuclei on a $^9$Be target at intermediate energies. So far it had been implemented and applied only to low energy reactions with light projectiles. The IAV model is successful in pred...

Angular distributions of quasielastic scattering and breakup of the neutron-rich halo nucleus ¹¹Be on a ²⁰⁸Pb target at an incident energy of 140 MeV (about 3.5 times the Coulomb barrier) were measured at HIRFL-RIBLL. A strong suppression of the Coulomb nuclear interference peak is observed in the measured quasielastic scattering angular distributi...

The Continuum-Discretized Coupled-Channels (CDCC) has been successfully employed to describe elastic and breakup of nuclear reactions induced by weakly bound projectiles. In this contribution, we review some other, less widespread applications of the CDCC wavefunction, some of them in combination with other reaction formalisms, which are being curr...

We present preliminary data of elastic scattering and inclusive breakup cross sections for the ⁷ Li+ ¹¹⁹ Sn reaction, recently measured at the Laboratori Nazionali del Sud (LNS-INFN) (Catania, Italy) at energies around the Coulomb barrier (E lab = 21.2 and 26.5 MeV). The experimental data have been analyzed under the Optical Model and Continuum-Dis...

This white paper reports on the discussions of the 2018 Facility for Rare Isotope Beams Theory Alliance (FRIB-TA) topical program ‘From bound states to the continuum: Connecting bound state calculations with scattering and reaction theory’. One of the biggest and most important frontiers in nuclear theory today is to construct better and stronger b...

New experimental results for the elastic scattering of 6He on 64Zn at incident energies of 15.0 and 18.0 MeV and 4He at 17.5 MeV along with results already published at 10.0 and 13.6 MeV, are presented. Elastic and alpha experimental cross sections are compared with coupled-reaction-channel, continuum-discretized coupledchannel, and DWBA inclusive-...

The Lagrange-mesh R-matrix method is generalized to inhomogeneous equations. This method is numerically stable and efficient. It can be directly used for transfer reactions with the formalism discussed by Ascuitto and Glendenning [Phys. Rev. 181, 1396 (1969)] and for inclusive breakup reactions modeled by Ichimura, Austern, and Vincent [Phys. Rev....

The Lagrange-mesh $R$-matrix method is generalized to inhomogeneous equations. This method is numerically stable and efficient. It can be directly used for transfer reactions with the formalism discussed by Ascuitto and Glendenning [Phys. Rev. 181,1396 (1969)] and for inclusive breakup reactions modeled by Ichimura, Austern, and Vincent [Phys. Rev....

Starting from an effective three-body Hamiltonian consisting of realistic two-body potentials, we solve the Faddeev-AGS equations for \(d+\alpha \) scattering using the separable expansion method. First, we construct separable representations of the two-body interactions and solve one-dimensional integral equations to obtain angular distributions f...

One of the biggest and most important frontiers in nuclear theory today is to construct better and stronger bridges between bound state calculations and calculations in the continuum, in particular scattering and reaction theory, as well as teasing out the influence of the continuum on states near threshhold. This is particular challenging as most...

Collisions between complex nuclei may give rise to their total or partial fusion. The latter case is found experimentally to gain importance when one of the colliding nuclei is weakly bound. It has been commonly assumed that the partial fusion mechanism is a two-step process, whose first step is the dissociation of the weakly bound nucleus, followe...

The Continuum-Discretized Coupled-Channels (CDCC) has been successfully employed to describe elastic and breakup of nuclear reactions induced by weakly bound projectiles. In this contribution, we review some other, less widespread applications of the CDCC wavefunction, some of them in combination with other reaction formalisms, which are being curr...

Background: Deuteron-induced reactions are widely used to probe nuclear structure and astrophysical information. Those (d,p) reactions may be viewed as three-body reactions and described with Faddeev techniques.

We reexamine the elastic and breakup observables of the Be11+64Zn reaction at the near-barrier energy of 28.7 MeV. The measured quasi-elastic data are compared with CDCC and extended CDCC (XCDCC) calculations, the latter including the effect of the 10Be deformation.The angular distribution of emitted 10Be fragments, reported in the original analysi...

{\bf Background} Deuteron induced reactions are widely used to probe nuclear structure and astrophysical information. Those (d,p) reactions may be viewed as three-body reactions and described with Faddeev techniques. {\bf Purpose} Faddeev-AGS equations in momentum space have a long tradition of utilizing separable interactions in order to arrive at...

New experimental results for the elastic scattering of He6 on Zn64 at incident energies of 15.0 and 18.0 MeV and He4 at 17.5 MeV along with results already published at 10.0 and 13.6 MeV, are presented. Elastic and α experimental cross sections are compared with coupled-reaction-channel, continuum-discretized coupled-channel, and DWBA inclusive-bre...

Experimental studies of nuclear collisions involving light weakly-bound nuclei show a systematic suppression of the complete fusion cross section by $\sim$30\% with respect to the expectation for tightly bound nuclei, at energies above the Coulomb barrier. Although it is widely accepted that the phenomenon is related to the weak binding of these nu...

We present the first example of a rigorous uncertainty quantification on elastic Nucleus-Nucleus scattering at energies near the Coulomb barrier. Experimental data has been analyzed using an energy dependent effective optical model potential with physical constraints imposed. We confirm the compatibility of these uncertainties with the well known C...

We present the first example of a rigorous uncertainty quantification on elastic Nucleus-Nucleus scattering at energies near the Coulomb barrier. Experimental data has been analyzed using an energy dependent effective optical model potential with physical constraints imposed. We confirm the compatibility of these uncertainties with the well known C...

We treat Li6 as an effective three-body (n−p−α) system and compute the d−αS-wave scattering length and three-body separation energy of Li6 for a wide variety of nucleon-nucleon and α-nucleon potentials which have the same (or nearly the same) phase shifts. The Coulomb interaction in the p−α subsystem is omitted. The results of all calculations lie...

We treat ${}^6$Li as an effective three-body ($n$-$p$-$\alpha$) system and compute the $d$-$\alpha$ $S-$wave scattering length and three-body separation energy of ${}^6$Li for a wide variety of nucleon-nucleon and $\alpha$-nucleon potentials which have the same (or nearly the same) phase shifts. The Coulomb interaction in the $p$-$\alpha$ subsystem...

This is a brief report on the progress made towards an exact theory for (d,p) on heavy nuclei, which is important to determine neutron capture rates for r-process nuclei. We first discuss the role of core excitation in the framework of Faddeev equations. Following that, we provide the status of the Faddeev theory being developed in the Coulomb basi...

Background: Deuteron induced reactions are widely used to probe nuclear structure and astrophysical information. Those (d,p) reactions may be viewed as three-body reactions and described with Faddeev techniques. Purpose: Faddeev equations in momentum space have a long tradition of utilizing separable interactions in order to arrive at sets of coupl...

The angular momentum basis method is introduced to solve the inclusive breakup within the model proposed by Ichimura, Austern, and Vincent [Phys. Rev. C 32, 431 (1985)]. This method is based on the geometric transformation between Jacobi coordinates, thus it is easy to corporate with particle spins. To test the validity of this partial wave expansi...

In this paper, we address the problem of the post-prior equivalence in the calculation of inclusive breakup and transfer cross sections. For that, we employ the model proposed by Ichimura, Austern, and Vincent [Phys. Rev. C 32, 431 (1985)], conveniently generalized to include the part of the cross section corresponding the transfer to bound states....

In this paper, we address the problem of the post-prior equivalence in the calculation of inclusive breakup and transfer cross sections. For that, we employ the model proposed by Ichimura, Austern, and Vincent [Phys. Rev. C 32, 431 (1985)], conveniently generalized to include the part of the cross section corresponding the transfer to bound states....

{\bf Background:} Deuteron induced reactions are widely used to probe nuclear structure and astrophysical information. Those (d,p) reactions may be viewed as three-body reactions and described with Faddeev techniques. {\bf Purpose:} Faddeev equations in momentum space have a long tradition of utilizing separable interactions in order to arrive at s...

We present an account of the current status of the theoretical treatment of inclusive $(d,p)$ reactions in the breakup--fusion formalism, pointing to some applications and making the connection with current experimental capabilities. Three independent implementations of the reaction formalism have been recently developed, making use of different nu...

We present an account of the current status of the theoretical treatment of inclusive $(d,p)$ reactions in the breakup-fusion formalism, pointing to some applications and making the connection with current experimental capabilities. Three independent implementations of the reaction formalism have been recently developed, making use of different num...

Background: Large $\alpha$ yields have been reported over the years in reactions with $^{6}$Li and $^{7}$Li projectiles. Previous theoretical analyses have shown that the elastic breakup (EBU) mechanism (i.e., projectile breakup leaving the target in its ground state) is able to account only for a small fraction of the total $\alpha$ inclusive brea...

We investigated the 238U(d,p) reaction as a surrogate for the n + 238U reaction. For this purpose we measured for the first time the gamma-decay and fission probabilities of 239U* simultaneously and compared them to the corresponding neutron-induced data. We present the details of the procedure to infer the decay probabilities, as well as a thoroug...

The problem of the calculation of inclusive breakup cross sections in nuclear reactions is reexamined. For that purpose, the theory proposed by Ichimura et al. (Phys Rev C 32:431, 1985) is revisited, both in its prior and post representations. We briefly outline the connection of this theory with that proposed by Udagawa and Tamura (Phys Rev C 24:1...

In 1980s Ichimura, Austern and Vincent [Phys.Rev.C 32, 431 (1985)] proposed a quantum mechanical theory to study the problem of inclusive breakup cross sections in the nuclear reactions. Using the DWBA version of this model, applications to deuteron and 6Li inclusive breakup reactions are presented and compared with some available data.

In 1980s Ichimura, Austern and Vincent [Phys. Rev. C 32 431 (1985)] proposed a theory to calculate the inclusive breakup cross sections. Using the finite range DWBA version of this theory, we have performed calculations for the \(^{118}\)Sn(d, pX) inclusive breakup reaction, and compared with available data in order to assess the applicability of t...

Fission and gamma decay probabilities of 237U and 239Np have been measured, for the first time simultaneously in dedicated experiments, via the surrogate reactions 238U(3He, 4He) and 238U(3He,d), respectively. While a good agreement between our data and neutron-induced data is found for fission probabilities, gamma decay probabilities are several t...

We address the problem of the post-prior equivalence in inclusive breakup reactions induced by weakly-bound nuclei. The problem is studied within the DWBA model of Ichimura, Austern, Vincent [Phys. Rev. C32, 431 (1985)]. The post and prior formulas obtained in this model are briefly recalled, and applied to several breakup reactions induced by deut...

The elastic resonance scattering protons decayed from $^{11}$B to the ground state of $^{10}$Be were measured using the thick-target technique in inverse kinematics at the Heavy Ion Research Facility in Lanzhou (HIRFL). The obtained excitation functions were well described by a multichannel R-matrix procedure under the kinematics process assumption...

A telescope array composed of a silicon strip detector and scintillator crystals is dedicated to detect reaction products induced by radioactive ion beams. The silicon strip detector has a thickness of 1000 μm and is divided into 40 × 40 strips with 1 mm resolution. The crystal array consists of 8 × 8 CsI (Tl) crystals with readouts by photo-multip...

The elastic scattering of 8 B by a nat Pb target was measured at an incident energy of 170.3 MeV. Special care was taken with the limited intensity and broad profile of the secondary beam. The measured angular distribution of the differential cross section shows that the Coulomb-nuclear interference peak (CNIP) is not suppressed in this system, in...

The elastic scattering of 8 B by a nat Pb target was measured at an incident energy of 170.3 MeV. Special care was taken with the limited intensity and broad profile of the secondary beam. The measured angular distribution of the differential cross section shows that the Coulomb-nuclear interference peak (CNIP) is not suppressed in this system, in...

Angular distributions for the elastic scattering of 7 Be and 8 B by an enriched 208 Pb target were measured at the Radioactive Ion Beam Line at Lanzhou (RIBLL). The incident energies of the radioactive beams were about three times the respective Coulomb barriers. A suppressed Coulomb-nuclear Interference Peak (CNIP) is not observed for 8 B, a prono...

a b s t r a c t A method is presented for the measurement of differential cross-sections of heavy ion elastic scattering induced by Radioactive Ion Beams (RIBs) on the Radioactive Ion Beam Line in Lanzhou (RIBLL) at the Heavy-Ion Research Facility in Lanzhou (HIRFL). The disadvantages of broad beam profiles and limited intensities of the RIBs were...

DOI:https://doi.org/10.1103/PhysRevC.87.019901

A new methodology is presented to analyze the threshold anomaly and to compare different kinds of reaction systems together. In this methodology, the experimental and theoretical values of the quarter-point angle are compared directly for different reaction systems. A suitable reduction method is employed to minimize the system effects. This new me...

Subbarrier fusion of the 7 Li+ 12 C reaction is studied using an antisymmetrized molecular dynamics model (AMD) with an after burner, GEMINI. In AMD, 7 Li shows an α + t structure at its ground state and it is significantly deformed. Simulations are made near the Coulomb barrier energies, i.e., Ecm = 3 − 8M eV . The total fusion cross section of th...

This Brief Report presents a phenomenological formula of total reaction cross sections for different reaction systems at low energies, taking into account the case of weakly bound nuclei as projectiles. To get this phenomenological formula, a large set of experimental data were collected and compared. Based on the experimental total reaction cross...