Nuclear Theory·nucl-th

Friday·February 25, 2022

6 papers—3 primary·3 cross-listed

01
[Submitted on 23 Feb 2022]
Ab initio informed evaluation of the radiative capture of protons on $^{7}$ Be
Konstantinos Kravvaris🇺🇸 · Petr Navrátil🇨🇦 · Sofia Quaglioni🇺🇸 · Chloë Hebborn🇺🇸 · Guillaume Hupin🇫🇷
The radiative capture of protons by $^{7}$ Be, which is the source of $^{8}$ B that $β$ -decays emitting the majority of solar neutrinos measured on earth, has not yet been measured at astrophysically relevant energies. The recommended value for its zero-energy S-factor, $S_{17}$ (0) = 20.8 $\pm$ (0.7)exp $\pm$ (1.4)theory eV $\cdot$ b, relies on theoretical extrapolations from higher-energy measurements, a process that leads to significant uncertainty. We performed a set of first-principle (or, ab initio) calculations of the $^{7}$ Be( $p$ , $γ$ ) $^{8}$ B reaction to provide an independent prediction of the low-energy S-factor with quantified uncertainties. We demonstrate underlying features in the predicted S-factor allowing the combination of theoretical calculations and measurements to produce an evaluated S-factor of $S_{17}$ (0) = 19.8 $\pm$ 0.3 eV $\cdot$ b. We expect the calculations and uncertainty quantification process described here to set a new standard for the evaluation of light-ion astrophysical reactions.
Comments:
7 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2202.11759 [pdf]
PLB(2023)·32 citations
02
[Submitted on 24 Feb 2022]
Deep learning on nuclear mass and $α$ decay half-lives
Chen-Qi Li · Chao-Nan Tong · Hong-Jing Du · Long-Gang Pang
Ab-initio calculations of nuclear masses, the binding energy and the $α$ decay half-lives are intractable for heavy nucleus, because of the curse of dimensionality in many body quantum simulations as proton number( $N$ ) and neutron number( $Z$ ) grow. We take advantage of the powerful non-linear transformation and feature representation ability of deep neural network(DNN) to predict the nuclear masses and $α$ decay half-lives. For nuclear binding energy prediction problem we achieve standard deviation $σ = 0.263$ MeV on 10-fold cross validation on 2149 nuclei. Word-vectors which are high dimensional representation of nuclei from the hidden layers of mass-regression DNN help us to calculate $α$ decay half-lives. For this task, we get $σ = 0.797$ on 100 times 10-fold cross validation on 350 nuclei on $l o g_{10} T_{1/2}$ and $σ = 0.731$ on 486 nuclei. We also find physical a priori such as shell structure, magic numbers and augmented inputs inspired by Finite Range Droplet Model are important for this small data regression task.
Comments:
17 pages
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2202.11897 [pdf]
PRC(2022)·49 citations
03
[Submitted on 24 Feb 2022]
Delta-resonances and hyperons in proto-neutron stars and merger remnants
Armen Sedrakian🇩🇪 · Arus Harutyunyan🇦🇲
The equation of state (EoS) and composition of dense and hot $Δ$ -resonance admixed hypernuclear matter is studied under conditions that are characteristic of neutron star binary merger remnants and supernovas. The cold, neutrino free regime is also considered as a reference for the astrophysical constraints on the EoS of dense matter. Our formalism uses the covariant density functional (CDF) theory successfully adapted to include the full $J^{P} = 1/ 2^{+}$ baryon octet and non-strange members of $J^{P} = 3/ 2^{+}$ decouplet with density-dependent couplings that have been suitably adjusted to the existing laboratory and astrophysical data. The effect of $Δ$ -resonances at finite temperatures is to soften the EoS of hypernuclear matter at intermediate densities and stiffen it at high densities. At low temperatures, the heavy baryons $Λ$ , $Δ^{-}$ , $Ξ^{-}$ , $Ξ^{0}$ and $Δ^{0}$ appear in the given order if the $Δ$ -meson couplings are close to those for the nucleon-meson couplings. As is the case for hyperons, the thresholds of $Δ$ -resonances move to lower densities with the increase of temperature indicating a significant fraction of $Δ$ 's in the low-density subnuclear regime. We find that the $Δ$ -resonances comprise a significant fraction of baryonic matter, of the order of $10%$ at temperatures of the order of several tens of MeV in the neutrino-trapped regime and, thus, may affect the supernova and binary neutron star dynamics by providing, for example, a new source for neutrino opacity or a new channel for bulk viscosity via the direct Urca processes. The mass-radius relation of isentropic static, spherically symmetric hot compact stars is discussed.
Comments:
v3: matches published version. v2: Version accepted in Euro. Phys. Journ. A, 15 pages, 11 figures. v1: 12 pages, 7 figures. Contribution to the EPJ A topical issue "CompOSE: a repository for Neutron Star Equations of State and Transport Properties"
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
2202.12083 [pdf]
EPJA(2022)·41 citations
04
[Submitted on 24 Feb 2022] (cross-list from hep-ph)
Nuclear medium effects in lepton-nucleus DIS in the region of $x ≳ 1$
M. Sajjad Athar🇮🇳 · S. K. Singh🇮🇳 · F. Zaidi🇮🇳
The nuclear medium effects in the nuclear structure functions and differential cross sections in the deep inelastic scattering (DIS) of charged lepton and neutrino from nuclear targets are studied in the region of large $x$ including $x \geq 1$ . The nuclear medium effects due to the Fermi motion and the binding energy of nucleons and the nucleon correlations are included using nucleon spectral function calculated in a microscopic field theoretical model. The numerical results for the nuclear structure functions and the cross sections are obtained using the nucleon structure function evaluated at the next-to-next-to-leading order (NNLO) with the Martin-Motylinski-Harland Lang-Thorne (MMHT) parameterization of the nucleonic parton distribution functions (PDFs) and are compared with the available experimental data on electron scattering from the Jefferson Lab (JLab) and SLAC Nuclear Physics Facility (NPAS). In the case of neutrino scattering the results are relevant for understanding the DIS contributions to the recent inclusive cross sections measured by the Main Injector Neutrino ExpeRiment to study v-A interactions (MINERvA) as well as theoretical predictions are made for Deep Underground Neutrino Experiment (DUNE). The importance of isoscalarity corrections in heavier nuclear targets as well as the effect of the kinematic cut on the CM energy $W$ in defining the DIS region have also been discussed.
Comments:
14 pages, 7 figures and 1 table
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2202.11892 [pdf]
PRD(2022)·5 citations
05
[Submitted on 24 Feb 2022] (cross-list from hep-ph)
Coherent $J / ψ$ electroproduction on $^{4}$ He and $^{3}$ He at the Electron-Ion Collider: probing nuclear shadowing one nucleon at a time
V. Guzey (St. Petersburg, INP)🇷🇺 · M. Rinaldi (Perugia U. and INFN, Perugia)🇮🇹 · S. Scopetta (Perugia U. and INFN, Perugia)🇮🇹 · M. Strikman (Penn State U.)🇺🇸 · M. Viviani (INFN, Pisa)🇮🇹
While the phenomenon of gluon nuclear shadowing at small $x$ has been getting confirmation in QCD analyses of various LHC measurements involving heavy nuclei, it has not been possible so far to establish experimentally the number of target nucleons responsible for nuclear shadowing in a given process. To address this issue, we study coherent $J / ψ$ electroproduction on $^{4}$ He and $^{3}$ He in the kinematics of a future electron-ion collider and show that this process has the power to disentangle the contributions of the interaction with a specific number of nucleons $k$ , in particular, with two nucleons at the momentum transfer $t \neq = 0$ . We predict a dramatic shift of the $t$ -dependence of the differential cross section toward smaller values of $∣ t ∣$ due to a non-trivial correlation between $x$ and $k$ . This calculation, which makes use for the first time of realistic wave functions, provides a stringent test of models of nuclear shadowing and a novel probe of the 3D imaging of gluons in light nuclei. In addition, thanks to this analysis, unique information on the real part of the corresponding scattering amplitude could be accessed.
Comments:
7 pages, 7 figures, Supplemental Material. Final published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2202.12200 [pdf]
PRL(2022)·5 citations
06
[Submitted on 24 Feb 2022] (cross-list from astro-ph.HE)
Oscillating magnetised hybrid stars under the magnifying glass of multi-messenger observations
Mauro Mariani🇦🇷 · Lucas Tonetto🇮🇹 · M. Camila Rodríguez🇦🇷 · Marcos O. Celi🇦🇷 · Ignacio F. Ranea-Sandoval🇦🇷 · Milva G. Orsaria🇦🇷 · Aurora Pérez Martínez🇪🇸
We model neutron stars as magnetised hybrid stars with an abrupt hadron-quark phase transition in their cores, taking into account current constraints from nuclear experiments and multi-messenger observations. We include magnetic field effects considering the Landau level quantisation of charged particles and the anomalous magnetic moment of neutral particles. We construct the magnetised hybrid equation of state, and we compute the particle population, the matter magnetisation and the transverse and parallel pressure components. We integrate the stable stellar models, considering the dynamical stability for \emph{rapid} or \emph{slow} hadron-quark phase conversion. Finally, we calculate the frequencies and damping times of the fundamental and $g$ non-radial oscillation modes. The latter, a key mode to learn about phase transitions in compact objects, is only obtained for stars with slow conversions. For low magnetic fields, we find that one of the objects of the GW170817 binary system might be a hybrid star belonging to the slow extended stability branch. For magnetars, we find that a stronger magnetic field always softens the hadronic equation of state. Besides, only for some parameter combinations a stronger magnetic field implies a higher hybrid star maximum mass. Contrary to previous results, the incorporation of anomalous magnetic moment does not affect the studied astrophysical quantities. We discuss possible imprints of the microphysics of the equation of state that could be tested observationally in the future, and that might help infer the nature of dense matter and hybrid stars.
Comments:
Accepted for publication in MNRAS (February 2022)
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2202.12222 [pdf]
MNRAS(2022)·22 citations

Affiliations

first authorsco-authorsvia INSPIRE

Ab initio informed evaluation of the radiative capture of protons on 7Be

Deep learning on nuclear mass and α decay half-lives

Delta-resonances and hyperons in proto-neutron stars and merger remnants

Nuclear medium effects in lepton-nucleus DIS in the region of x≳1

Coherent J/ψ electroproduction on 4He and 3He at the Electron-Ion Collider: probing nuclear shadowing one nucleon at a time

Oscillating magnetised hybrid stars under the magnifying glass of multi-messenger observations

Affiliations

Ab initio informed evaluation of the radiative capture of protons on $^{7}$ Be

Deep learning on nuclear mass and $α$ decay half-lives

Nuclear medium effects in lepton-nucleus DIS in the region of $x ≳ 1$

Coherent $J / ψ$ electroproduction on $^{4}$ He and $^{3}$ He at the Electron-Ion Collider: probing nuclear shadowing one nucleon at a time