Nuclear Theory·nucl-th

Wednesday·July 8, 2020

6 papers—4 primary·2 cross-listed

01
[Submitted on 1 Jul 2020]
Why can hadronic stars convert into strange quark stars with larger radii
Alessandro Drago🇮🇹 · Giuseppe Pagliara🇮🇹
The total binding energy of compact stars is the sum of the gravitational binding energy $(B E)_{g}$ and the nuclear binding energy $(B E)_{n}$ , the last being related to the microphysics of the interactions. While the first is positive (binding) both for hadronic stars and for strange quark stars, the second is large and negative for hadronic stars (anti-binding) and either small and negative (anti-binding) or positive (binding) for strange quark stars. A hadronic star can convert into a strange quark star with a larger radius because the consequent reduction of $(B E)_{g}$ is over-compensated by the large increase in $(B E)_{n}$ . Thus, the total binding energy increases due to the conversion and the process is exothermic. Depending on the equations of state of hadronic matter and quark matter and on the baryonic mass of the star, the contrary is obviously also possible, namely the conversion of hadronic stars into strange quark stars having smaller radii, a situation more often discussed in the literature. We provide a condition that is sufficient and in most of the phenomenologically relevant cases also necessary in order to form strange quark stars with larger radii while satisfying the exothermicity request. Finally, we compare the two schemes in which quark stars are produced (one having large quark stars and the other having small quark stars) among themselves and with the third-family scenario and we discuss how present and future data can discriminate among them.
Comments:
8 pages, 4 figures, revised version accepted for publication
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2007.03436 [pdf]
PRD(2020)·22 citations
02
[Submitted on 7 Jul 2020]
Comparison of Different Methods for Calculation of the Normalized Mott Cross Section
P.B. Kats🇧🇾 · K.V. Halenka · O.O. Voskresenskaya🇷🇺
An intercomparison of some earlier methods for calculating the normalized Mott cross section and also a method proposed by the authors of the present work is carried out. It is demonstrated that applying the given method, along with the method of Lijian et al., is preferable for relevant calculations.
Comments:
12 pages, 1 table, 2 figures, PDF
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2007.03622 [pdf]
0 citations
03
[Submitted on 7 Jul 2020]
Efficient emulators for scattering using eigenvector continuation
R.J. Furnstahl🇺🇸 · A.J. Garcia🇺🇸 · P.J. Millican🇺🇸 · Xilin Zhang🇺🇸
Eigenvector continuation EC has been shown to accurately and efficiently reproduce ground states for targeted sets of Hamiltonian parameters. It uses as variational basis vectors the corresponding ground-state eigensolutions from selected other sets of parameters. Here we extend the EC approach to scattering using the Kohn variational principle. We first test it using a model for S-wave nucleon-nucleon scattering and then demonstrate that it also works to give accurate predictions for non-local potentials, charged-particle scattering, complex optical potentials, and higher partial waves. These proofs-of-principle validate EC as an accurate emulator for applying Bayesian inference to parameter estimation constrained by scattering observables. The efficiency of such emulators is because the accuracy is achieved with a small number of variational basis elements and the central computations are just linear algebra calculations in the space spanned by this basis.
Comments:
Typos in Eqs~(7) and (8) are corrected. Erratum will be submitted
Subjects:
Nuclear Theory (nucl-th); cond-mat.mtrl-sci (cond-mat.mtrl-sci); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2007.03635 [pdf]
PLB(2020)·79 citations
04
[Submitted on 7 Jul 2020]
Cross sections for coherent elastic and inelastic neutrino-nucleus scattering
N. Van Dessel🇧🇪 · V. Pandey🇺🇸 · H. Ray🇺🇸 · N. Jachowicz🇧🇪
The prospects of extracting new physics signals in coherent elastic neutrino--nucleus scattering (CE $ν$ NS) processes are limited by the precision with which the underlying nuclear structure physics, embedded in the weak nuclear form factor, is known. We present calculations of charge and weak nuclear form factors and CE $ν$ NS cross sections on $^{12}$ C, $^{16}$ O, $^{40}$ Ar, $^{56}$ Fe and $^{208}$ Pb nuclei. We obtain the proton and neutron densities, and charge and weak form factors by solving Hartree--Fock (HF) equations with a Skyrme (SkE2) nuclear potential. We validate our approach by comparing $^{208}$ Pb and $^{40}$ Ar charge form factor predictions with available elastic electron scattering data. Since CE $ν$ NS experiments at stopped--pion sources are also well suited to measure inelastic charged--current and neutral--current neutrino--nucleus cross sections, we also present calculations for these processes, incorporating a continuum Random Phase Approximation (CRPA) description on top of the HF-SkE2 picture of the nucleus. Providing both coherent as well as inelastic cross sections in a consistent framework, we aim at obtaining a reliable and detailed comparison of the strength of these processes in the energy region below ~100 MeV. Furthermore, we attempt to gauge the level of theoretical uncertainty pertaining to the description of the $^{40}$ Ar form factor and CE $ν$ NS cross sections by comparing relative differences between recent microscopic nuclear theory and widely--used phenomenological form factor predictions. Future precision measurements of CE $ν$ NS will potentially help in constraining these nuclear structure details that will in turn improve prospects of extracting new physics.
Comments:
Invited article for the Special Issue "Many Body Theory" of the Universe journal. Published version. 28 pages, 12 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2007.03658 [pdf]
Universe(2023)·33 citations

Affiliations

first authorsco-authorsvia INSPIRE

Why can hadronic stars convert into strange quark stars with larger radii

Comparison of Different Methods for Calculation of the Normalized Mott Cross Section

Efficient emulators for scattering using eigenvector continuation

Cross sections for coherent elastic and inelastic neutrino-nucleus scattering

Affiliations