Nuclear Theory·nucl-th

Tuesday·December 29, 2020

15 papers—9 primary·6 cross-listed

10
[Submitted on 26 Dec 2020] (cross-list from astro-ph.HE)
Correlation between the curvature and some properties of the neutron star
S. K. Biswal · H. C. Das · Ankit Kumar · Bharat Kumar · Rashmita Jena · Padmalaya Dash · S. K. Patra
According to the general theory of relativity, a massive body induces curvature in the surrounding spacetime. In this study, the surface curvature (SC) of neutron stars is computed using various curvature quantities derived from the relativistic mean-field, density-dependent RMF, and Skyrme-Hartree-Fock equations of states. Neutron star properties, including mass, radius, compactness, and central density, are calculated utilizing the Tolman-Oppenheimer-Volkoff equations. The analysis reveals a significant cubic correlation between the SC and compactness for the canonical 1.4 $M_{⊙}$ neutron star, with a correlation coefficient of 0.99, indicating an almost linear relationship. A similarly significant inverse cubic correlation is observed between the SC and the radius of the canonical star. However, these correlations diminish for the maximum mass NS. Furthermore, a universal relation between the SC and the dimensionless tidal deformability ( $Λ$ ) for the canonical neutron star is established. Using the tidal deformability constraint of GW170817 ( $Λ_{1.4} = 19 0_{- 120}^{+ 390}$ ), the surface curvature is limited to SC $_{1.4} (1 0^{14}) = 2.8 7_{- 0.78}^{+ 0.30}$ at a confidence level 90\%. Furthermore, the tidal deformability constraint of the secondary component in the GW190814 event ( $Λ_{1.4} = 61 6_{- 158}^{+ 273}$ ) offers a more stringent limit, with the result of SC $_{1.4} (1 0^{14}) = 2.0 3_{- 0.36}^{+ 0.27}$ . These findings indicate that the GW190814 event imposes more rigorous constraints on SC compared to GW170817.
Comments:
16 pages, 5 figures, Published in IJMPE
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2012.13673 [pdf]
IJMPE(2025)·7 citations
11
[Submitted on 26 Dec 2020] (cross-list from hep-ph)
Sphaleron Transition Rates and the Chiral Magnetic Effect
Joseph I. Kapusta🇺🇸 · Ermal Rrapaj🇺🇸 · Serge Rudaz🇺🇸
The chiral magnetic effect is a novel quantum phenomenon proposed for high-energy nuclear collisions but which has yet to be observed. We quantify the axial charge relaxation time, due to sphalerons, which enters in simulations of this effect. An extrapolation of weak coupling calculations of the sphaleron rate yields rather different relaxation times than strong coupling AdS/CFT calculations. The AdS/CFT relaxation time is the larger one of the two by an order of magnitude, but the weak coupling relaxation time may not be reliable because it is only marginally bigger than the microscopic thermalization time. The role of quark masses has yet to be accurately assessed.
Comments:
11 pages, 5 figures, published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2012.13784 [pdf]
IJMPE(2022)·2 citations
12
[Submitted on 26 Dec 2020] (cross-list from nucl-ex)
Laser spectroscopy of neutron-rich $^{207, 208}$ Hg isotopes: Illuminating the kink and odd-even staggering in charge radii across the $N = 126$ shell closure
T. Day Goodacre🇬🇧 · A.V. Afanasjev🇺🇸 · A.E. Barzakh🇷🇺 · B.A. Marsh🇨🇭 · S. Sels🇨🇭 · P. Ring🇩🇪 · H. Nakada🇯🇵 · A.N. Andreyev🇬🇧 · P. Van Duppen🇧🇪 · N.A. Althubiti🇬🇧 · B. Andel🇧🇪 · D. Atanasov🇩🇪 and 32 other authors
The mean-square charge radii of $^{207, 208}$ Hg ( $Z = 80, N = 127, 128$ ) have been studied for the first time and those of $^{202, 203, 206}$ Hg ( $N = 122, 123, 126$ ) remeasured by the application of in-source resonance-ionization laser spectroscopy at ISOLDE (CERN). The characteristic \textit{kink} in the charge radii at the $N = 126$ neutron shell closure has been revealed, providing the first information on its behavior below the $Z = 82$ proton shell closure. A theoretical analysis has been performed within relativistic Hartree-Bogoliubov and non-relativistic Hartree-Fock-Bogoliubov approaches, considering both the new mercury results and existing lead data. Contrary to previous interpretations, it is demonstrated that both the kink at $N = 126$ and the odd-even staggering (OES) in its vicinity can be described predominately at the mean-field level, and that pairing does not need to play a crucial role in their origin. A new OES mechanism is suggested, related to the staggering in the occupation of the different neutron orbitals in odd- and even- $A$ nuclei, facilitated by particle-vibration coupling for odd- $A$ nuclei.
Comments:
7 pages, 5 figures, Physical Review C, in press
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2012.13802 [pdf]
PRL(2021)·79 citations
13
[Submitted on 27 Dec 2020] (cross-list from hep-ph)
Fun with colours: the standard model with two colour QCD has radically different long distance physics
Saumen Datta🇮🇳 · Sourendu Gupta🇮🇳 · Rishi Sharma🇮🇳
In our world the standard model of particle physics contains within it the fairly intractable theory called QCD. A toy version with two colours is often studied as a model confining and chiral symmetry breaking field theory. Here we investigate the cascade of changes at various distance scales if we make this change within the standard model. It is possible to limit the changes at the hadronic scale. However, the minor changes that occur actually cascade down to the far infrared, into nuclear and atomic physics, and chemistry. Through this it also possibly affects the evolution of stars and galaxies. We remark on this unexpected sensitivity of the universe to physics at the scale of quarks.
Comments:
Submitted to Indian Journal of Physics memorial issue for Pushan Majumdar
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2012.13856 [pdf]
Indian J.Phys.(2021)·2 citations
14
[Submitted on 27 Dec 2020] (cross-list from hep-ph)
Residual Mean Field Model of Valence Quarks in the Nucleon
Christopher Leon🇺🇸 · Misak Sargsian🇺🇸
We develop a non-perturbative model for valence parton distribution functions (PDFs) based on the mean field interactions of valence quarks in the nucleonic interior. The main motivation for the model is to obtain a mean field description of the valence quarks as a baseline to study the short range quark-quark interactions that generate the high $x$ tail of PDFs. The model is based on the separation of the valence three-quark cluster and residual system in the nucleon. Then the nucleon structure function is calculated within the effective light-front diagrammatic approach introducing nonperturbative light-front valence quark and residual wave functions. Within the model a new relation is obtained between the position, $x_{p}$ , of the peak of $x q_{V} (x)$ distribution of the valence quark and the effective mass of the residual system, $m_{R}$ , in the form: $x_{p} \approx \frac{1}{4} (1 - \frac{m _{R}}{m _{N}})$ at starting $Q^{2}$ . This relation explains the difference in the peak positions for d- and u- quarks through the expected difference of residual masses for valence d- and u- quark distributions. The parameters of the model are fixed by fitting the calculated valence quark distributions to the phenomenological PDFs. This allowed us to estimate the overall mean field contribution in baryonic and momentum sum rules for valence d- and u- quarks. Finally, the evaluated parameters of the non-perturbative wave functions of valence 3q-cluster and residual system can be used in calculation of other quantities such as nucleon form factors, generalized partonic and transverse momentum distributions.
Comments:
45 pages and 13 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2012.14030 [pdf]
EPJC(2022)·5 citations
15
[Submitted on 28 Dec 2020] (cross-list from hep-ph)
Prospects for quarkonium studies at the high-luminosity LHC
Emilien Chapon🇨🇳 · David d'Enterria🇨🇭 · Bertrand Ducloue🇬🇧 · Miguel G. Echevarria🇪🇸 · Pol-Bernard Gossiaux🇫🇷 · Vato Kartvelishvili🇬🇧 · Tomas Kasemets🇩🇪 · Jean-Philippe Lansberg🇫🇷 · Ronan McNulty🇮🇪 · Darren D. Price🇬🇧 · Hua-Sheng Shao🇫🇷 · Charlotte Van Hulse🇮🇪 and 39 other authors
Prospects for quarkonium-production studies accessible during the upcoming high-luminosity phases of the CERN Large Hadron Collider operation after 2021 are reviewed. Current experimental and theoretical open issues in the field are assessed together with the potential for future studies in quarkonium-related physics. This will be possible through the exploitation of the huge data samples to be collected in proton-proton, proton-nucleus and nucleus-nucleus collisions, both in the collider and fixed-target modes. Such investigations include, among others, those of: (i) J/psi and Upsilon produced in association with other hard particles; (ii) chi(c,b) and eta(c,b) down to small transverse momenta; (iii) the constraints brought in by quarkonia on gluon PDFs, nuclear PDFs, TMDs, GPDs and GTMDs, as well as on the low-x parton dynamics; (iv) the gluon Sivers effect in polarised-nucleon collisions; (v) the properties of the quark-gluon plasma produced in ultra-relativistic heavy-ion collisions and of collective partonic effects in general; and (vi) double and triple parton scatterings.
Comments:
Latex, 115 pages, 55 figures, 4 tables. v2: Review published in Progress in Particle and Nuclear Physics
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2012.14161 [pdf]
PPNP(2022)·169 citations

Affiliations

first authorsco-authorsvia INSPIRE

Correlation between the curvature and some properties of the neutron star

Sphaleron Transition Rates and the Chiral Magnetic Effect

Laser spectroscopy of neutron-rich 207,208Hg isotopes: Illuminating the kink and odd-even staggering in charge radii across the N=126 shell closure

Fun with colours: the standard model with two colour QCD has radically different long distance physics

Residual Mean Field Model of Valence Quarks in the Nucleon

Prospects for quarkonium studies at the high-luminosity LHC

Affiliations

Laser spectroscopy of neutron-rich $^{207, 208}$ Hg isotopes: Illuminating the kink and odd-even staggering in charge radii across the $N = 126$ shell closure