Nuclear Theory·nucl-th

Thursday·November 4, 2021

9 papers—5 primary·4 cross-listed

01
A $γ$ -rigid solution of the Bohr Hamiltonian with deformation-dependent mass term for Kratzer potential and $γ = 3 0^{\circ}$
S. Ait El Korchi · S. Baid · P. Buganu · M. Chabab · A. El Batoul · A. Lahbas · M. Oulne
In this work, the Davydov-Chaban Hamiltonian, describing the collective motion of $γ$ -rigid atomic nuclei, is amended by allowing the mass parameter to depend on the nuclear deformation. Further, Z(4)-DDM (Deformation-Dependent Mass) model is proposed by considering the Kratzer potential for the $β$ variable, and solving the problem by techniques of asymptotic iteration method (AIM). The results of the calculated spectra and $B (E 2)$ transition rates for series of $^{192 - 196}$ Pt isotopes are compared with the corresponding experimental data as well as with other theoretical models. Exact analytical expressions are derived for spectra and normalized wave functions of the Kratzer potential. The obtained results show an overall good agreement with the experimental data and an important improvement in respect to other models
nucl-thBulg.J.Phys.(2021)·2 citations
02
Efficacy of the symmetry-adapted basis for ab initio nucleon-nucleus interactions for light- and intermediate-mass nuclei
Alexis Mercenne · Kristina D. Launey · Tomas Dytrych · Jutta E. Escher · Sofia Quaglioni · Grigor H. Sargsyan · Jerry P. Draayer
We study the efficacy of a new ab initio framework that combines the symmetry-adapted (SA) no-core shell-model approach with the resonating group method (RGM) for unified descriptions of nuclear structure and reactions. We obtain ab initio neutron-nucleus interactions for $^{4}$ He, $^{16}$ O, and $^{20}$ Ne targets, starting with realistic nucleon-nucleon potentials. We discuss the effect of increasing model space sizes and symmetry-based selections on the SA-RGM norm and direct potential kernels, as well as on phase shifts, which are the input to calculations of cross sections. We demonstrate the efficacy of the SA basis and its scalability with particle numbers and model space dimensions, with a view toward ab initio descriptions of nucleon scattering and capture reactions up through the medium-mass region.
nucl-thComput.Phys.Commun.(2022)·20 citations
03
Three-boson stability for boosted interactions towards the zero-range limit
K. Mohseni🇧🇷 · A. J. Chaves🇧🇷 · D. R. da Costa🇧🇷 · T. Frederico🇧🇷 · M. R. Hadizadeh🇨🇳
We study the three-boson bound-state mass and wave functions for ground and excited states within the three-body relativistic framework with Kamada and Glöcke boosted potentials in the limit of a zero-range interaction. We adopt a nonrelativistic short-range separable potential, with Yamaguchi and Gaussian form factors, and drive them towards the zero-range limit by letting the form factors' momentum scales go to large values while keeping the two-body binding fixed. We show that the three-boson relativistic masses and wave functions are model-independent towards the zero-range limit, and the Thomas collapse is avoided, while the nonrelativistic limit kept the Efimov effect. Furthermore, the stability in the zero-range limit is a result of the reduction of boosted potential with the increase of the virtual pair center of mass momentum within the three-boson system. Finally, we compare the present results with Light-Front and Euclidean calculations.
nucl-thphysics.comp-phPLB(2021)·6 citations
04
Parity and Time Reversal Invariance Violation in Neutron-Nucleus Scattering
V. V. Flambaum🇦🇺 · A. J. Mansour🇦🇺
Parity violating (PV) as well as parity and time-reversal invariance violating (PTRIV) effects are enhanced a million times in neutron reactions near p-wave compound resonances. We present the calculation of such effects using a statistical theory based on the properties of chaotic eigenstates and discuss a possibility to extract the strength constants of PTRIV interactions from the experimental data, including nucleon-nucleon and pion-nucleon CP-violating interactions, the QCD theta-term and the quark chromo-EDM. PV effects have random sign for all target nuclei except for 232Th, where PV effects of a positive sign have been observed for ten statistically significant p-wave resonances, with energy smaller than 250 eV. This may be an indication of a possible regular (non-chaotic) contribution to PV effects. We link this regular effect to the doublets of opposite parity states in the rotation spectra of nuclei with an octupole deformation and suggest other target nuclei where this hypothesis may be tested. We also discuss a permanent sign contribution produced by doorway states. An estimate of the ratio of PTRIV effects to PV effects is presented. Although a polarised target is not needed for the measurement of PV effects, for the interpretation of the results, it may be convenient to do both PV and PTRIV experiments with a polarised target.
nucl-thhep-phPRC(2022)·8 citations
05
Shell-model study of titanium isotopic chain with chiral two- and three-body forces
L. Coraggio · G. De Gregorio · A. Gargano · N. Itaco · T. Fukui · Y. Z. Ma · F. R. Xu
The even-even Ti isotopic chain, from A = 42 to 70, has been studied within the nuclear shell-model framework by employing an effective Hamiltonian which is derived by way of many-body perturbation theory from a chiral potential with two- and three-body forces, and includes three-body contributions which account for Pauli principle violations in nuclei with more than two valence particles. We consider 40Ca as a closed core and a model space spanned by the neutron and proton 0f1p orbitals with the addition of the 0g9/2 orbital for neutrons. Calculated two-neutron separation energies and excitation energies of the yrast 2+ states are reported and compared with the experimental data, which are available up to 62Ti. The present study intends to investigate the effects of the adopted effective interactions on the evolution of the shell structure.
nucl-thPRC(2021)·15 citations
06
Neutron-Mirror Neutron oscillations in Matter
Yuri Kamyshkov🇺🇸 · James Ternullo🇺🇸 · Louis Varriano🇺🇸 · Zurab Berezhiani🇮🇹
The possibility that a neutron can be transformed to a hidden sector particle remains intriguingly open. Proposed theoretical models conjecture that the hidden sector can be represented by a mirror sector, and the neutron n can oscillate into its sterile mirror twin n', exactly or nearly degenerate in mass with n. Oscillations n - n' can take place in vacuum and in the environment of the regular matter and the magnetic field where only neutron will be subject of interaction with the environment. We describe the propagation of the oscillating n - n' system as a particle of the cold neutron beam passing through the dense absorbing materials in connection with the possible regeneration type of experiments where the effect of n -> n' -> n transformation can be observed.
↳ hep-phnucl-exnucl-thSymmetry(2022)·19 citations
07
The transversity parton distribution function of the nucleon using the pseudo-distribution approach
Colin Egerer🇺🇸 · Christos Kallidonis🇺🇸 · Joseph Karpie🇺🇸 · Nikhil Karthik🇺🇸 · Christopher J. Monahan🇺🇸 · Wayne Morris🇺🇸 · Kostas Orginos🇺🇸 · Anatoly Radyushkin🇺🇸 · Eloy Romero🇺🇸 · Raza Sabbir Sufian🇺🇸 · Savvas Zafeiropoulos🇫🇷
We present a determination of the non-singlet transversity parton distribution function (PDF) of the nucleon, normalized with respect to the tensor charge at $μ^{2} = 2$ GeV $^{2}$ from lattice quantum chromodynamics. We apply the pseudo-distribution approach, using a gauge ensemble with a lattice spacing of 0.094 fm and the light quark mass tuned to a pion mass of 358 MeV. We extract the transversity PDF from the analysis of the short-distance behavior of the Ioffe-time pseudo-distribution using the leading-twist next-to-leading order (NLO) matching coefficients calculated for transversity. We reconstruct the $x$ -dependence of the transversity PDF through an expansion in a basis of Jacobi polynomials in order to reduce the PDF ansatz dependence. Within the limitations imposed by a heavier-than-physical pion mass and a fixed lattice spacing, we present a comparison of our estimate for the valence transversity PDF with the recent global fit results based on single transverse spin asymmetry. We find the intrinsic nucleon sea to be isospin symmetric with respect to transversity.
↳ hep-lathep-exhep-phnucl-thPRD(2022)·54 citations
08
A New Constraint on the Nuclear Equation of State from Statistical Distributions of Compact Remnants of Supernovae
Mikhail M. Meskhi · Noah E. Wolfe · Zhenyu Dai · Carla Frohlich · Jonah M. Miller · Raymond K. W. Wong · Ricardo Vilalta
Understanding how matter behaves at the highest densities and temperatures is a major open problem in both nuclear physics and relativistic astrophysics. This physics is often encapsulated in the so-called high-temperature nuclear equation of state, which influences compact binary mergers, core-collapse supernovae, and many more phenomena. One such case is the type (either black hole or neutron star) and mass of the remnant of the core collapse of a massive star. For each of six candidate equations of state, we use a very large suite of spherically symmetric supernova models to generate a suite of synthetic populations of such remnants. We then compare these synthetic populations to the observed remnant population. We thus provide a novel constraint on the high-temperature nuclear equation of state and describe which EOS candidates are more or less favored by this metric.
↳ astro-ph.HEnucl-thApJL(2022)·11 citations
09
On the nature of the mass-gap object in the GW190814 event
Luiz L. Lopes🇧🇷 · Debora P. Menezes🇧🇷
In this work, we make a very extensive study on the conditions that allow the mass-gap object in the GW190814 event to be faced as a degenerate star instead of a black hole. We begin revisiting some parametrizations of the Quantum Hadrodynamics (QHD) and then study under which conditions the hyperons are present in such a massive star. Afterward, using a vector MIT based model, we study if self-bound quark stars, satisfying the Bodmer-Witten conjecture fulfill all the observational constraints. Finally, we study hybrid stars within a Maxwell construction and check for what values of the bag, as well as the vector interaction, a quark core star with only nucleons, and with nucleons admixed with hyperons can reach at least 2.50 M $_{⊙}$ . We conclude that, depending on the choice of parameters, none of the possibilities can be completely ruled out, i.e., the mass-gap object can be a hadronic (either nucleonic or hyperonic), a quark, or a hybrid star. However, some cases are more probable than others.
↳ hep-phastro-ph.HEnucl-thApJ(2022)·45 citations

Affiliations

first authorsco-authorsvia INSPIRE