Nuclear Theory·nucl-th

Tuesday·September 22, 2020

9 papers—5 primary·4 cross-listed

01
[Submitted on 18 Sept 2020]
SU(3)-guided Realistic Nucleon-nucleon Interactions for Large-scale Calculations
G. H. Sargsyan · K. D. Launey · R. B. Baker · T. Dytrych · J. P. Draayer
We examine nucleon-nucleon realistic interactions, based on their SU(3) decomposition to SU(3)-symmetric components. We find that many of these interaction components are negligible, which, in turn, allows us to identify a subset of physically relevant components that are sufficient to describe the structure of low-lying states in $^{12}$ C and related observables, such as excitation energies, electric quadrupole transitions and rms radii. We find that paring the interaction down to half of the SU(3)-symmetric components or more yields results that practically coincide with the corresponding ab initio calculations with the full interaction. In addition, we show that while various realistic interactions differ in their SU(3) decomposition, their renormalized effective counterparts exhibit a striking similarity and composition that can be linked to dominant nuclear features such as deformation, pairing, clustering, and spin-orbit effect.
Comments:
9 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2009.09001 [pdf]
PRC(2021)·6 citations
02
[Submitted on 19 Sept 2020]
Dichotomy of Baryons as Quantum Hall Droplets and Skyrmions In Compact-Star Matter
Yong-Liang Ma🇨🇳 · Mannque Rho🇫🇷
We review the recent exploration of a possible "domain-wall structure" of compressed baryonic matter in massive compact stars in terms of fractional quantum Hall droplets and skyrmions for baryons in medium. The theoretical framework is anchored on an effective nuclear effective field theory that incorporates two hidden symmetries, flavor local symmetry and scale symmetry conjectured to be dual to the gluons and quarks of QCD. It hints at a basically different, hitherto undiscovered structure of nuclear matter at low as well as high densities. Hidden "genuine dilaton (GD)" symmetry and hidden local symmetry (HLS) gauge-equivalent at low density to nonlinear sigma model capturing chiral symmetry, put together in nuclear effective field theory, are seen to play an increasingly important role in providing hadron-quark duality in baryonic matter. This strongly motivates incorporating both symmetries in formulating "first-principles" approaches to nuclear dynamics encompassing from the nuclear matter density to the highest density stable in the Universe.
Comments:
15 pages, 2 figures, invited review for Symmetry 2021
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2009.09219 [pdf]
Symmetry(2021)·28 citations
03
[Submitted on 19 Sept 2020]
Coupled-channel treatment of $^{7} Li (n, γ)^{8} Li$ in effective field theory
Renato Higa🇧🇷 · Pradeepa Premarathna🇺🇸 · Gautam Rupak🇺🇸
The E1 contribution to the capture reaction $^{7} Li (n, γ)^{8} Li$ is calculated at low energies. We employ a coupled-channel formalism to account for the $^{7} Li^{⋆}$ excited core contribution. We develop a halo effective field theory power counting where capture in the spin $S = 2$ channel is enhanced over the $S = 1$ channel. A next-to-leading order calculation is presented where the excited core contribution is shown to affect only the overall normalization of the cross section. The momentum dependence of the capture cross section, as a consequence, is the same in a theory with or without the excited $^{7} Li^{⋆}$ degree of freedom at this order of the calculation. The kinematical signature of the $^{7} Li^{⋆}$ core is negligible at momenta below 1 MeV and significant only beyond the $3^{+}$ resonance energy, though still compatible with a next-to-next-to-leading order correction. We compare our formalism with a previous halo effective field theory calculation [Zhang, Nollett, and Phillips, Phys. Rev. C 89, 024613 (2014)] that also treated the $^{7} Li^{⋆}$ core as an explicit degree of freedom. Our formal expressions and analysis disagree with this earlier work in several aspects.
Comments:
17 pages, 7 figures, 3 tables, updated manuscript, results unchanged
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex)
arXiv:
2009.09324 [pdf]
EPJA(2021)·7 citations
04
[Submitted on 21 Sept 2020]
Collectivity in large and small systems formed in ultrarelativistic collisions
Rajeev S Bhalerao🇮🇳
Collective flow of the final-state hadrons observed in ultrarelativistic heavy-ion collisions or even in smaller systems formed in high-multiplicity pp and p/d/ $^{3}$ He-nucleus collisions is one of the most important diagnostic tools to probe the initial state of the system and to shed light on the properties of the short-lived, strongly-interacting many-body state formed in these collisions. Limited, in the initial years, to the study of mainly the directed and elliptic flows -- the first two Fourier harmonics of the single-particle azimuthal distribution -- this field has evolved in recent years into a much richer area of activity. This includes not only higher Fourier harmonics and multiparticle cumulants, but also a variety of other related observables, such as the ridge seen in two-particle correlations, flow decorrelation, symmetric cumulants and event-plane correlators which measure correlations between the magnitudes or phases of the complex flows in different harmonics, coefficients that measure the nonlinear hydrodynamic response, statistical properties, such as the non-Gaussianity of the flow fluctuations, etc. We present a Tutorial Review of the modern flow picture and the various aspects of the collectivity -- an emergent phenomenon in quantum chromodynamics.
Comments:
Invited review article for EPJ ST, pedagogical review article, 34 pages, 14 Figs, 14 Exercises, comments welcome
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2009.09586 [pdf]
Eur.Phys.J.ST(2021)·19 citations
05
[Submitted on 21 Sept 2020]
Quadrupole dominance in the light Sn and in the Cd isotopes
A. P. Zuker🇫🇷
[Background] The BE2 rates of the Sn isotopes for $N \leq 64$ exhibit enhancements hitherto unexplained. The same is true for the Cd isotopes. [Purpose] Describe the electromagnetic properties of the Sn and Cd isotopes [Method] Shell model calculations with a minimally renormalized realistic interaction, supplemented by Quasi and Pseudo-SU3 symmetries and Nilsson-SU3 selfconsistent calculations. [Results for $N \leq 64$ ] Shell model calculations with the neutron effective charge as single free parameter describe well the BE2(2>0) and BE2(4>2) rates for $N \leq 64$ in the Cd and Sn isotopes. The former exhibit weak permanent deformation corroborating the prediction of a Pseudo-SU3 symmetry, which remains of heuristic value in the latter, where the pairing force erodes the quadrupole dominance. Calculations in $1 0^{7}$ and $1 0^{10}$ -dimensional spaces exhibit almost identical patterns: A vindication of the shell model. [Results for $N \geq 64$ ] Nilsson-SU3 calculations describe BE2 patterns in [112-120]Cd and [116-118]Sn isotopes having sizable quadrupole moment of non-rotational origin denoted as q-vibrations. No calculations are proposed for the heavier species, for which the conventional seniority dscription is assumed for Sn, while in Cd the quadrupole moments change sign. [Conclusion] A radical reexamination of traditional interpretations in the region has been shown to be necessary, in which quadrupole dominance plays a major role. What emerges is a bumpy but coherent view.
Comments:
10 pages 8 figures This is a radical revision of arXiv:1905.11479 which was accepted as a PRC rapid communication. I proposed a fully revised paper (the present one). The editors accepted. To avoid confusion, this article should be treated as a new submission. It is twice as long as the original and contains fundamental addition and improvements
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2009.09636 [pdf]
PRC(2021)·22 citations
06
[Submitted on 20 Sept 2020] (cross-list from hep-ph)
Chiral Symmetry Restoration and Deconfinement in the Contact Interaction Model of Quarks with a Parallel Electric and Magnetic Fields
Aftab Ahmad🇵🇰
We study the impact of steady, homogeneous, and external parallel electric and magnetic field strength ( $e E ∥ e B$ ), on the chiral symmetry breaking-restoration and confinement-deconfinement phase transitions. We also sketch the phase diagram of quantum chromodynamics (QCD) at finite temperature $T$ and in the presence of background fields. Our unified formalism for this study is based on the Schwinger-Dyson equations, symmetry preserving vector-vector contact interaction model of quarks, and the proper time regularization scheme. At $T = 0$ , in the purely magnetic case ( $e E \to 0$ ), we observe the well known magnetic catalysis effect. On the other hand, in the pure electric field background ( $e B \to 0$ ), the electric field tends to restore the chiral symmetry and deconfinement above the pseudo-critical electric field $e E_{c}^{χ, C}$ . In the presence of both $e E$ and $e B$ : we find the magnetic catalysis effect in the particular region where $e B$ dominates over $e E$ , whereas, we observe the chiral inhibition (or electric chiral rotation) effect, when $e E$ stand over $e B$ . At finite $T$ , in the pure electric field case, the phenomenon of inverse electric catalysis appears to exist in our model. On the other hand for pure magnetic field background, we notice the magnetic catalysis effect in the mean-field approximation and inverse magnetic catalysis with $e B$ -dependent coupling. The combined effect of both $e E$ and $e B$ on the pseudo-critical $T_{c}^{χ, C}$ yields the inverse electromagnetic catalysis, with and without $e B -$ dependent effective coupling of the model. Our findings are satisfactory in agreement with already predicted results by lattice simulations and other reliable effective models of QCD.
Comments:
11 pages, 21 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2009.09482 [pdf]
CPC(2021)·12 citations
07
[Submitted on 21 Sept 2020] (cross-list from hep-ph)
Flow coefficients in O-O Al-Al and Cu-Cu collisions at 200 GeV in the fusing color string model
M.A. Braun🇷🇺 · C. Pajares🇪🇸
In view of the planning experiments for collisions of light nuclei at RHIC the flow coefficients for O-O, Al-AL and Cu-Cu collisions are studied in the color string percolation model. Our results for $v_{2}$ are somewhat smaller than predicted by other groups although with the same dependence on centrality. Our obtained $v_{3}$ lie between predictions of other groups.
Comments:
11 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2009.09667 [pdf]
PRC(2021)·0 citations
08
[Submitted on 21 Sept 2020] (cross-list from nucl-ex)
Comment on "A sensitivity study of the primary correlators used to characterize chiral-magnetically-driven charge separation'' by Magdy, Nie, Ma, and Lacey
Yicheng Feng🇺🇸 · Fuqiang Wang🇺🇸 · Jie Zhao🇺🇸
This note points out an apparent error in the publication Phys.~Lett.~B {\bf 809} (2020) 135771 by Magdy, Nie, Ma, and Lacey.
Comments:
3 pages, 1 figure, 1 table
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2009.10057 [pdf]
1 citation
09
[Submitted on 21 Sept 2020] (cross-list from astro-ph.HE)
Near-critical supernova outflows and their neutrino signatures
Alexander Friedland (SLAC)🇺🇸 · Payel Mukhopadhyay (SLAC and Stanford U.)🇺🇸
We demonstrate that the neutrino-driven outflows inside exploding core-collapse supernovae possess a special property of near-criticality, that is, they are on the edge of forming termination shocks. We derive a novel criterion for the formation of the shock, in terms of the fundamental parameters of the problem: the neutrino luminosity and energy as well as the properties of the protoneutron star. The criterion provides a unified description of the available numerical results and motivates future simulations. The property of near-criticality makes the neutrino signatures of the termination shocks a sensitive diagnostic of the physical conditions around the PNS several seconds into the explosion. The expected signal at DUNE is found to be statistically significant.
Comments:
14 pages, 6 figures, updated version published in Phys. Lett. B
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2009.10059 [pdf]
PLB(2022)·16 citations

Affiliations

first authorsco-authorsvia INSPIRE