Nuclear Theory·nucl-th

Wednesday·April 29, 2020

8 papers—3 primary·5 cross-listed

01
12B(n,gamma)13B reaction as alternative path to astrophysical synthesis of 13C isotope
S.B. Dubovichenko · N.A. Burkova · A.V. Dzhazairov-Kakhramanov · A.Yertaiuly
The total cross sections of the neutron radiative capture on 12B at astrophysical energies to the ground state of 13B have been calculated in the energy range of 10E-8 to 10 MeV within the framework of a modified potential cluster model with the classification of orbital states according to Young diagrams. Reaction rates in the temperature range of 0.01 to 10 T9 and their analytical parameterization were obtained. The calculated rates of 12B(n,gamma)13B excess the previous results by approximately to one order. Cross sections and reaction rates of 12C(n,gamma)13C are calculated and compared to the n10B, n11B, n12B, and p12C reaction rates. It is proposed that obtained rates of the 12B(n,gamma)13B reaction should be taken into account in novel scenarios of stable isotope 13C synthesis without of 12C hydrogen burning.
nucl-thNPA(2021)·2 citations
02
Ab initio calculations of low-energy nuclear scattering using confining potential traps
Xilin Zhang🇺🇸 · S. R. Stroberg🇺🇸 · P.Navrátil🇨🇦 · Chan Gwak🇨🇦 · J. A. Melendez🇺🇸 · R. J. Furnstahl🇺🇸 · J. D. Holt🇨🇦
A recently modified method to enable low-energy nuclear scattering results to be extracted from the discrete energy levels of the target-projectile clusters confined by harmonic potential traps is tested. We report encouraging results for neutron-- $α$ and neutron-- $^{24} O$ elastic scattering from analyzing the trapped levels computed using two different ab initio nuclear structure methods. The $n$ -- $α$ results have also been checked against a direct ab initio reaction calculation. The $n$ -- $^{24} O$ results demonstrate the approach's applicability for a large range of systems provided their spectra in traps can be computed by ab initio methods. A key ingredient is a rigorous understanding of the errors in the calculated energy levels caused by inevitable Hilbert-space truncations in the ab initio methods.
nucl-thhep-latPRL(2020)·39 citations
03
The Lagrange-mesh R-matrix method for inhomogenous equations
Jin Lei🇮🇹 · Pierre Descouvemont🇧🇪
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. C 32, 431 (1985)]. We first present a simple example to assess the method. Then the application to the $^{93}$ Nb( $d$ , $pX$ ) non-elastic breakup is discussed.
nucl-thPRC(2020)·6 citations
04
Intrinsic Transverse Momentum and Evolution in Weighted Spin Asymmetries
Jian-Wei Qiu🇺🇸 · Ted C. Rogers🇺🇸 · Bowen Wang🇨🇳
The transverse momentum dependent (TMD) and collinear higher twist theoretical factorization frameworks are the most frequently used approaches to describing spin dependent hard cross sections weighted by and integrated over transverse momentum. Of particular interest is the contribution from small transverse momentum associated with the target bound state. In phenomenological applications, this contribution is often investigated using transverse momentum weighted integrals that sharply regulate the large transverse momentum contribution, for example with Gaussian parametrizations. Since the result is a kind of hybrid of TMD and collinear (inclusive) treatments, it is important to establish if and how the formalisms are related in applications to weighted integral observables. The suppression of a large transverse momentum tail, for example, can potentially affect the type of evolution that is applicable. We find that a naive version of a widely used identity relating the $k_{T}^{2}$ -weighted and integrated Sivers TMD function to a renormalized twist-3 function has strongly ambiguous ultraviolet contributions, and that corrections to it are not necessarily perturbatively suppressed. We discuss the implications for applications, arguing in particular that the relevant evolution for transverse momentum weighted and integrated cross sections with sharp effective large transverse momentum cutoffs is of the TMD form rather than the standard renormalization group evolution of collinear correlation functions.
↳ hep-phnucl-thPRD(2020)·17 citations
05
Status of the search for $η$ -mesic nuclei with particular focus on $η$ -Helium bound states
Magdalena Skurzok🇵🇱
In this paper the search for eta-mesic nuclei with particular focus on light $η$ -He bound states is reviewed. A brief description of recent theoretical studies and experimental results is presented.
↳ nucl-exnucl-thFew Body Syst.(2021)·4 citations
06
The newly observed $Λ_{b} (6072)^{0}$ structure and its $ρ -$ mode nonstrange partners
Wei Liang🇨🇳 · Qi-Fang Lü🇨🇳
Inspired by the newly observed $Λ_{b} (6072)$ structure, we investigate its strong decay behaviors under various assignments within the $^{3} P_{0}$ model. Compared with the mass and total decay width, our results suggest that the $Λ_{b} (6072)$ can be regarded as the lowest $ρ -$ mode excitation in $Λ_{b}$ family. Then, the strong decays of $ρ -$ mode nonstrange partners for the $Λ_{b} (6072)$ are calculated. It is found that the $J^{P} = 5/ 2^{-}$ $Λ_{b}$ and $Λ_{c}$ states are relatively narrow, and mainly decay into the $Σ_{b}^{(*)} π$ and $Σ_{c}^{(*)} π$ final states, respectively. These two states have good potentials to be observed in future experiments, which may help us to distinguish the three-quark model and diquark model.
↳ hep-phhep-exnucl-thEPJC(2020)·13 citations
07
Enhanced dynamics in fusion of neutron-rich oxygen nuclei at above-barrier energies
S. Hudan · R.T. deSouza · A.S. Umar · Z. Lin · C.J. Horowitz
Above-barrier fusion cross-sections for an isotopic chain of oxygen isotopes with A=16-19 incident on a $^{12}$ C target are presented. Experimental data are compared with both static and dynamical microscopic calculations. These calculations are unable to explain the $\sim$ 37\% increase in the average above-barrier fusion cross-section observed for $^{19}$ O as compared to $β$ -stable oxygen isotopes. This result suggests that for neutron-rich nuclei existing time-dependent Hartree-Fock calculations underpredict the role of dynamics at near-barrier energies. High-quality measurement of above-barrier fusion for an isotopic chain of increasingly neutron-rich nuclei provides an effective means to probe this fusion dynamics.
↳ nucl-exnucl-thPRC(2020)·13 citations
08
Program to calculate coefficients of transformations between three-particle hyperspherical harmonics
Victor D. Efros
A program to calculate the three-particle hyperspherical brackets is presented. Test results are listed and it is seen that the program is well applicable up to very high values of the hypermomentum and orbital momenta. The listed runs show that it is also very fast. Applications of the brackets to calculating interaction matrix elements and constructing hyperspherical bases for identical particles are described. Comparisons are done with the programs published previously.
↳ physics.comp-phnucl-thphysics.atom-phComput.Phys.Commun.(2020)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE