Nuclear Theory·nucl-th

Monday·February 26, 2018

9 papers—4 primary·5 cross-listed

01
[Submitted on 23 Feb 2018]
Quark-Meson-Coupling (QMC) model for finite nuclei, nuclear matter and beyond
P. A. M. Guichon🇫🇷 · J. R. Stone🇬🇧 · A. W. Thomas🇦🇺
The Quark-Meson-Coupling model, which self-consistently relates the dynamics of the internal quark structure of a hadron to the relativistic mean fields arising in nuclear matter, provides a natural explanation to many open questions in low energy nuclear physics, including the origin of many-body nuclear forces and their saturation, the spin-orbit interaction and properties of hadronic matter at a wide range of densities up to those occurring in the cores of neutron stars. Here we focus on four aspects of the model (i) a full comprehensive survey of the theory, including the latest developments, (ii) extensive application of the model to ground state properties of finite nuclei and hypernuclei, with a discussion of similarities and differences between the QMC and Skyrme energy density functionals, (iii) equilibrium conditions and composition of hadronic matter in cold and warm neutron stars and their comparison with the outcome of relativistic mean-field theories and, (iv) tests of the fundamental idea that hadron structure changes in-medium.
Comments:
84 pages, 11 figures, in print in Progress in Particle and Nuclear Physics
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1802.08368 [pdf]
PPNP(2018)·104 citations
02
[Submitted on 23 Feb 2018]
Implications of Neutron Star Properties for the Existence of Light Dark Matter
T. F. Motta🇦🇺 · P. A. M. Guichon🇫🇷 · A. W. Thomas🇦🇺
It was recently suggested that the discrepancy between two methods of measuring the lifetime of the neutron may be a result of an unseen decay mode into a dark matter particle which is almost degenerate with the neutron. We explore the consequences of this for the properties of neutron stars, finding that their known properties are in conflict with the existence of such a particle.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1802.08427 [pdf]
J.Phys.G(2018)·77 citations
03
[Submitted on 23 Feb 2018]
The electric quadrupole channel of the 7.8 eV $^{229} Th$ transition
Pavlo V. Bilous · Nikolay Minkov · Adriana Pálffy
The unique isomeric transition at 7.8 eV in $^{229} Th$ has a magnetic dipole ( $M 1$ ) and an electric quadrupole ( $E 2$ ) multipole mixing. So far, the $E 2$ component has been widely disregarded. Here, we investigate the nuclear physics nature and the impact of the $E 2$ decay channel for the nuclear coupling to the atomic shell based on the newest theoretical predictions for the corresponding reduced nuclear transition probabilities. Our results show that the contribution of the $E 2$ channel is dominant or at least of the same order of magnitude for internal conversion or electronic bridge transitions involving the atomic orbitals $7 p$ , $6 d$ and $5 f$ . Notable exceptions are the internal conversion of the $7 s$ electron and the electronic bridge between the electronic states $7 s$ and $7 p$ , for which the $M 1$ component dominates by two to three orders of magnitude. Caution is therefore advised when considering isomeric excitation or decay via nuclear coupling to the atomic shell, as the involved orbitals determine which multipole transition component dominates.
Subjects:
Nuclear Theory (nucl-th); Atomic Physics (physics.atom-ph)
arXiv:
1802.08482 [pdf]
PRC(2018)·22 citations
04
[Submitted on 23 Feb 2018]
Few- and many-nucleon systems with semilocal coordinate-space regularized chiral nucleon-nucleon forces
S. Binder · A. Calci · E. Epelbaum · R.J. Furnstahl · J. Golak · K. Hebeler · T. Hüther · H. Kamada · H. Krebs · P. Maris · U.-G. Meißner · A. Nogga and 6 other authors
We employ a variety of ab initio methods including Faddeev-Yakubovsky equations, No-Core Configuration Interaction Approach, Coupled-Cluster Theory and In-Medium Similarity Renormalization Group to perform a comprehensive analysis of the nucleon-deuteron elastic and breakup reactions and selected properties of light and medium-mass nuclei up to 48Ca using the recently constructed semilocal coordinate-space regularized chiral nucleon-nucleon potentials. We compare the results with those based on selected phenomenological and chiral EFT two-nucleon potentials, discuss the convergence pattern of the chiral expansion and estimate the achievable theoretical accuracy at various chiral orders using the novel approach to quantify truncation errors of the chiral expansion without relying on cutoff variation. We also address the robustness of this method and explore alternative ways to estimate the theoretical uncertainty from the truncation of the chiral expansion.
Comments:
34 pages, 15 figures, 11 tables
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1802.08584 [pdf]
PRC(2018)·95 citations
05
[Submitted on 20 Feb 2018] (cross-list from hep-ph)
Lorentz-violating contributions to the nuclear Schiff moment and nuclear EDM
Jonas B. Araujo🇧🇷 · Rodolfo Casana🇧🇷 · Manoel M. Ferreira Jr🇧🇷
In the context of an atom endowed with nuclear electric dipole moment (EDM), we consider the effects on the Schiff moment of $C P T$ -even Lorentz-violating (LV) terms that modify the Coulomb potential. First, we study the modifications on the Schiff moment when the nucleus interacts with the electronic cloud by means of a Coulomb potential altered only by the $P$ -even LV components. Next, by supposing the existence of an additional intrinsic LV EDM generated by other LV sources, we assess the corrections to the Schiff moment when the interaction nucleus-electrons runs mediated by a Coulomb potential modified by both the $P$ -odd and $P$ -even LV components. We then use known estimates and EDM measurements to discuss upper bounds on the new Schiff moment components and the possibility of an intrisic nuclear EDM component ascribed to LV effects.
Comments:
8 pages, revtex style, Phys. Rev. D 97, 055032 (2018)
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1802.07365 [pdf]
PRD(2018)·11 citations
06
[Submitted on 22 Feb 2018] (cross-list from hep-ph)
Thermal Model Description of p--Pb Collisions at $s_{N N}$ = 5.02 TeV
Natasha Sharma🇮🇳 · Jean Cleymans🇿🇦 · Lokesh Kumar🇮🇳
The ALICE data on light flavor hadron production obtained in $p - P b$ collisions at $s_{N N}$ = 5.02 TeV are studied in the thermal model using the canonical approach with exact strangeness conservation. The chemical freeze-out temperature is independent of centrality except for the lowest multiplicity bin, with values close to 160 MeV but consistent with those obtained in $P b - P b$ collisions at $s_{N N}$ = 2.76 TeV. The value of the strangeness non-equilibrium factor $γ_{s}$ is slowly increasing with multiplicity from 0.9 to 0.96, i.e. it is always very close to full chemical equilibrium.
Comments:
10 pages, 12 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1802.07972 [pdf]
EPJC(2018)·19 citations
07
[Submitted on 22 Feb 2018] (cross-list from hep-ph)
When gluons go odd: how classical gluon fields generate odd azimuthal harmonics for the two-gluon correlation function in high-energy collisions
Yuri V. Kovchegov🇺🇸 · Vladimir V. Skokov🇺🇸
We show that, in the saturation/Color Glass Condensate framework, odd azimuthal harmonics of the two-gluon correlation function with a long-range separation in rapidity are generated by the higher-order saturation corrections in the interactions with the projectile and the target. At the very least, the odd harmonics require three scatterings in the projectile and three scatterings in the target. We derive the leading-order expression for the two-gluon production cross section which generates odd harmonics: the expression includes all-order interactions with the target and three interactions with the projectile. We evaluate the obtained expression both analytically and numerically, confirming that the odd-harmonics contribution to the two-gluon production in the saturation framework is non-zero.
Comments:
31 pages, 8 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1802.08166 [pdf]
PRD(2018)·41 citations
08
[Submitted on 22 Feb 2018] (cross-list from hep-ph)
Testing dark decays of baryons in neutron stars
Gordon Baym🇺🇸 · D. H. Beck🇺🇸 · Peter Geltenbort🇫🇷 · Jessie Shelton🇺🇸
We demonstrate that the observation of neutron stars with masses greater than one solar mass places severe demands on any exotic neutron decay mode that could explain the discrepancy between beam and bottle measurements of the neutron lifetime. If the neutron can decay to a stable, feebly-interacting dark fermion, the maximum possible mass of a neutron star is 0.7 solar masses, while all well-measured neutron star masses exceed one solar mass. The survival of $2 M_{⊙}$ neutron stars therefore indicates that any explanation beyond the Standard Model for the neutron lifetime puzzle requires dark matter to be part of a multi-particle dark sector with highly constrained interactions.
Comments:
4 pages, 7 figures. v2: relativistic corrections added, results shown for wider range of dark fermion masses, conclusions unchanged
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
1802.08282 [pdf]
PRL(2018)·123 citations
09
[Submitted on 23 Feb 2018] (cross-list from hep-ph)
A femtoscopic Correlation Analysis Tool using the Schrödinger equation (CATS)
D.L. Mihaylov🇩🇪 · V. Mantovani Sarti🇩🇪 · O.W. Arnold🇩🇪 · L. Fabbietti🇩🇪 · B. Hohlweger🇩🇪 · A.M. Mathis🇩🇪
We present a new analysis framework called "Correlation Analysis Tool using the Schrödinger equation" (CATS) which computes the two-particle femtoscopy correlation function $C (k)$ , with $k$ being the relative momentum for the particle pair. Any local interaction potential and emission source function can be used as an input and the wave function is evaluated exactly. In this paper we present a study on the sensitivity of $C (k)$ to the interaction potential for different particle pairs: p-p, p- $Λ$ , $K^{-}$ -p, $K^{+}$ -p, p- $Ξ^{-}$ and $Λ$ - $Λ$ . For the p-p Argonne $v_{18}$ and Reid Soft-Core potentials have been tested. For the other pair systems we present results based on strong potentials obtained from effective Lagrangians such as $χ$ EFT for p- $Λ$ , Jülich models for $K (K ˉ)$ -N and Nijmegen models for $Λ$ - $Λ$ . For the p- $Ξ^{-}$ pairs we employ the latest lattice results from the HAL QCD collaboration. Our detailed study of different interacting particle pairs as a function of the source size and different potentials shows that femtoscopic measurements can be exploited in order to constrain the final state interactions among hadrons. In particular, small collision systems of the order of 1~fm, as produced in pp collisions at the LHC, seem to provide a suitable environment for quantitative studies of this kind.
Comments:
16 pages, 13 figures, submitted to EPJ C
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1802.08481 [pdf]
EPJC(2018)·122 citations

Affiliations

first authorsco-authorsvia INSPIRE