Nuclear Theory·nucl-th

Thursday·January 6, 2022

8 papers—5 primary·3 cross-listed

06
Hyperon production in quasielastic $ν ˉ_{τ} -$ nucleon scattering
A. Fatima🇮🇳 · M. Sajjad Athar🇮🇳 · S. K. Singh🇮🇳
The theoretical results for the total cross sections and polarization components of the $τ^{+}$ lepton produced in the charged current induced $∣Δ S ∣ = 1$ quasielastic $ν ˉ_{τ} - N$ scattering leading to hyperons ( $Λ, Σ$ ) have been presented assuming T invariance. The theoretical uncertainties arising due to the use of different vector, axial vector and pseudoscalar form factors as well as the effect of SU(3) symmetry breaking have been studied. We have also presented, for the first time, a comparison of the total cross sections for the production of $e, μ, τ$ leptons to facilitate the implications of lepton flavor universality~(LFU) in the $∣Δ S ∣ = 1$ quasielastic reactions induced by the antineutrinos of all flavors i.e., $ν_{l}; l = e, μ, τ$ .
↳ hep-phhep-exnucl-thPRD(2022)·5 citations
07
The structure of $^{36}$ Ca under the Coulomb magnifying glass
L. Lalanne🇫🇷 · O. Sorlin🇫🇷 · A. Poves🇪🇸 · M. Assié🇫🇷 · F. Hammache🇫🇷 · S. Koyama🇯🇵 · F. Flavigny🇯🇵 · V. Girard-Alcindor🇫🇷 · A. Lemasson🇫🇷 · A. Matta🇫🇷 · T. Roger🇫🇷 · D. Beaumel🇫🇷 and 19 other authors
Detailed spectroscopy of the neutron-deficient nucleus $^{36}$ Ca was obtained up to 9 MeV using the $^{37}$ Ca( $p$ , $d$ ) $^{36}$ Ca and the $^{38}$ Ca( $p$ , $t$ ) $^{36}$ Ca transfer reactions. The radioactive nuclei, produced by the LISE spectrometer at GANIL, interacted with the protons of the liquid Hydrogen target CRYPTA, to produce light ejectiles (the deuteron $d$ or triton $t$ ) that were detected in the MUST2 detector array, in coincidence with the heavy residues %identified by a zero degree detection system. %States have been measured up to 9 MeV. Our main findings are: i) a similar shift in energy for the 1 $_{1}^{+}$ and 2 $_{1}^{+}$ states by about -250 keV, as compared to the mirror nucleus $^{36}$ S, ii) the discovery of an intruder 0 $_{2}^{+}$ state at 2.83(13) MeV, which appears below the first 2 $^{+}$ state, in contradiction with the situation in $^{36}$ S, and iii) a tentative 0 $_{3}^{+}$ state at 4.83(17) MeV, proposed to exhibit a bubble structure with two neutron vacancies in the 2s $_{1/2}$ orbit. The inversion between the 0 $_{2}^{+}$ and 2 $_{1}^{+}$ states is due to the large mirror energy difference (MED) of -516(130) keV for the former. This feature is reproduced by Shell Model (SM) calculations, using the $s d$ - $p f$ valence space, predicting an almost pure intruder nature for the 0 $_{2}^{+}$ state, with two protons (neutrons) being excited across the $Z$ =20 magic closure in $^{36}$ Ca ( $^{36}$ S). This mirror system has the largest MEDs ever observed, if one excludes the few cases induced by the effect of the continuum.
↳ nucl-exnucl-thPRL(2022)·24 citations
08
Neural network reconstruction of the dense matter equation of state from neutron star observables
Shriya Soma🇩🇪 · Lingxiao Wang🇩🇪 · Shuzhe Shi🇨🇦 · Horst Stöcker🇩🇪 · Kai Zhou🇩🇪
The Equation of State (EoS) of strongly interacting cold and hot ultra-dense QCD matter remains a major challenge in the field of nuclear astrophysics. With the advancements in measurements of neutron star masses, radii, and tidal deformabilities, from electromagnetic and gravitational wave observations, neutron stars play an important role in constraining the ultra-dense QCD matter EoS. In this work, we present a novel method that exploits deep learning techniques to reconstruct the neutron star EoS from mass-radius (M-R) observations. We employ neural networks (NNs) to represent the EoS in a model-independent way, within the range of $\sim$ 1-7 times the nuclear saturation density. The unsupervised Automatic Differentiation (AD) framework is implemented to optimize the EoS, so as to yield through TOV equations, an M-R curve that best fits the observations. We demonstrate that this method works by rebuilding the EoS on mock data, i.e., mass-radius pairs derived from a randomly generated polytropic EoS. The reconstructed EoS fits the mock data with reasonable accuracy, using just 11 mock M-R pairs observations, close to the current number of actual observations.
↳ hep-phastro-ph.HEastro-ph.IMnucl-thJCAP(2022)·57 citations

Affiliations

first authorsco-authorsvia INSPIRE

Hyperon production in quasielastic νˉτ​−nucleon scattering

The structure of 36Ca under the Coulomb magnifying glass

Neural network reconstruction of the dense matter equation of state from neutron star observables

Affiliations

Hyperon production in quasielastic $ν ˉ_{τ} -$ nucleon scattering

The structure of $^{36}$ Ca under the Coulomb magnifying glass