Nuclear Theory·nucl-th

Thursday·August 12, 2021

8 papers—3 primary·5 cross-listed

01
[Submitted on 10 Aug 2021]
Nuclear Dynamics and Reactions in the Ab Initio Symmetry-Adapted Framework
Kristina D. Launey · Alexis Mercenne · Tomas Dytrych
We review the ab initio symmetry-adapted (SA) framework for determining the structure of stable and unstable nuclei, along with related electroweak, decay and reaction processes. This framework utilizes the dominant symmetry of nuclear dynamics, the shape-related symplectic Sp(3,R) symmetry, which has been shown to emerge from first principles and to expose dominant degrees of freedom that are collective in nature, even in the lightest species or seemingly spherical states. This feature is illustrated for a broad scope of nuclei ranging from helium to titanium isotopes, enabled by recent developments of the ab initio symmetry-adapted no-core shell model expanded to the continuum through the use of the SA basis and that of the resonating group method. The review focuses on energies, electromagnetic transitions, quadrupole and magnetic moments, radii, form factors, and response function moments, for ground-state rotational bands and giant resonances. The method also determines the structure of reaction fragments that is used to calculate decay widths and alpha-capture reactions for simulated x-ray burst abundance patterns, as well as nucleon-nucleus interactions for cross sections and other reaction observables.
Comments:
26 pages, 7 figures, 1 table; in Annual Review of Nuclear and Particle Science
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
2108.04894 [pdf]
Ann.Rev.Nucl.Part.Sci.(2021)·56 citations
02
[Submitted on 10 Aug 2021]
Emergent symplectic symmetry in atomic nuclei: Ab initio symmetry-adapted no-core shell model
Kristina D Launey · Tomáš Dytrych · Grigor H Sargsyan · Robert B Baker · Jerry P Draayer
Exact symmetry and symmetry-breaking phenomena play a key role in gaining a better understanding of the physics of many-particle systems, from quarks and atomic nuclei, through molecules and galaxies. In nuclei, exact and dominant symmetries such as rotational invariance, parity, and charge independence have been clearly established. Beyond such symmetries, the nature of nuclear dynamics appears to exhibit a high degree of complexity, and only now, we show the fundamental role of an emergent approximate symmetry in nuclei, the symplectic Sp(3,R) symmetry, as clearly unveiled from ab initio studies that start from realistic interactions. In this article, we detail and enhance our recent findings presented in Physical Review Letters 124 (2020) 042501, that establish Sp(3,R) as a remarkably good symmetry of the strong interaction, and point to the predominance of a few equilibrium nuclear shapes (deformed or not) with associated vibrations and rotations that preserve the symplectic Sp(3,R) symmetry. Specifically, we find that the structure of nuclei below the calcium region in their ground state, as well as in their low-lying excited states and giant resonances, respects this symmetry at the 60-80% level.
Comments:
Part of collection "Role of Symmetries in Nuclear Physics", V.K.B. Kota and A.K. Jain (13 pages, 6 figures, 1 table). arXiv admin note: text overlap with arXiv:1810.05757
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2108.04900 [pdf]
Eur.Phys.J.ST(2020)·34 citations
03
[Submitted on 11 Aug 2021]
Dynamic modeling for heavy-ion collisions
Chun Shen🇺🇸
Recent theory progresses in (3+1)D dynamical descriptions of relativistic nuclear collisions at finite baryon density are reviewed. Heavy-ion collisions at different collision energies produce strongly coupled nuclear matter to probe the phase structure of Quantum Chromodynamics (QCD). Dynamical frameworks serve as a quantitative tool to study properties of hot QCD matter and map collisions to the QCD phase diagram. Outstanding challenges are highlighted when confronting theoretical models with the current and forthcoming experimental measurements from the RHIC beam energy scan program.
Comments:
6 pages, 2 figures, contribution to the 19th International Conference on Strangeness in Quark Matter (SQM2021)
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2108.04987 [pdf]
EPJ Web Conf.(2022)·8 citations
04
[Submitted on 10 Aug 2021] (cross-list from hep-ph)
Temperature dependence of the properties of open heavy-flavor mesons
Gloria Montana🇪🇸 · Angels Ramos🇪🇸 · Laura Tolos🇪🇸 · Juan M. Torres-Rincon🇩🇪
We address the modification of open heavy-flavor mesons in a hot medium of light mesons within an effective theory approach consistent with chiral and heavy-quark spin-flavor symmetries and the use of the imaginary time formalism to introduce the non-zero temperature effects to the theory. The unitarized scattering amplitudes, the ground-state self-energies and the corresponding spectral functions are calculated self-consistently. We use the thermal ground-state spectral functions obtained with this methodology to further calculate 1) open-charm meson Euclidean correlators, and 2) off-shell transport coefficients in the hadronic phase.
Comments:
4 pages, 4 figures, contribution to the proceedings for the 19th International Conference on Strangeness in Quark Matter (SQM 2021), online 17-22 May 2021 (Submission to EPJ)
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2108.04874 [pdf]
EPJ Web Conf.(2022)·3 citations
05
[Submitted on 10 Aug 2021] (cross-list from hep-ph)
Pion charge radius from pion+electron elastic scattering data
Zhu-Fang Cui🇨🇳 · Daniele Binosi🇮🇹 · Craig D. Roberts🇨🇳 · Sebastian M. Schmidt🇩🇪
With the aim of extracting the pion charge radius, we analyse extant precise pion+electron elastic scattering data on $Q^{2} \in [0.015, 0.144]$ GeV $^{2}$ using a method based on interpolation via continued fractions augmented by statistical sampling. The scheme avoids any assumptions on the form of function used for the representation of data and subsequent extrapolation onto $Q^{2} ≃ 0$ . Combining results obtained from the two available data sets, we obtain $r_{π} = 0.640 (7)$ fm, a value $2.4 σ$ below today's commonly quoted average. The tension may be relieved by collection and similar analysis of new precise data that densely cover a domain which reaches well below $Q^{2} = 0.015$ GeV $^{2}$ . Considering available kaon+electron elastic scattering data sets, our analysis reveals that they contain insufficient information to extract an objective result for the charged-kaon radius, $r_{K}$ . New data with much improved precision, low- $Q^{2}$ reach and coverage are necessary before a sound result for $r_{K}$ can be recorded.
Comments:
5 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2108.04948 [pdf]
PLB(2021)·26 citations
06
[Submitted on 11 Aug 2021] (cross-list from hep-ph)
Shear viscosity at finite baryon densities
Emma McLaughlin🇺🇸 · Jacob Rose🇩🇪 · Travis Dore🇺🇸 · Paolo Parotto🇩🇪 · Claudia Ratti🇺🇸 · Jacquelyn Noronha-Hostler🇺🇸
We use the excluded volume Hadron Resonance Gas (HRG) model with the most up-to-date hadron list to calculate $η T / w$ at low temperatures and at finite baryon densities $ρ_{B}$ . This $η T / w$ is then matched to a QCD-based shear viscosity calculation of the QGP for different profiles of $η T / w$ across {T, $μ_{B}$ } including cross-over and critical point transitions. When compared to ideal hydrodynamic trajectories across {T, $μ_{B}$ }, we find that the $η T / w (T, μ_{B})$ profiles would require initial conditions at much larger baryon density to reach the same freeze-out point.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2108.05300 [pdf]
EPJ Web Conf.(2022)·1 citation
07
[Submitted on 11 Aug 2021] (cross-list from hep-ph)
Interpretations of the new LHCb $P_{c} (4337)^{+}$ pentaquark state
Mao-Jun Yan🇨🇳 · Fang-Zheng Peng🇨🇳 · Mario Sánchez Sánchez🇫🇷 · Manuel Pavon Valderrama🇨🇳
Recently the LHCb collaboration has observed a new pentaquark state, the $P_{c} (4337)^{+}$ . Owing to its proximity to the $χ_{c 0} (1 S) p$ , $D ˉ^{*} Λ_{c}$ , $D ˉ Σ_{c}$ and $D ˉ Σ_{c}^{*}$ thresholds, this new pentaquark might very well be a meson-baryon bound state. However its spin and parity have not been determined yet and none of the previous possibilities can be ruled out. We briefly explore a few of these options and the consequences they entail in the present manuscript: (i) the $P_{c} (4337)^{+}$ might be a $χ_{c 0} (1 S) p$ bound state, (ii) the $P_{c} (4312)^{+}$ and $P_{c} (4337)^{+}$ might be $D ˉ^{*} Λ_{c}$ and $D ˉ Σ_{c}$ states close to threshold, respectively, where the Breit-Wigner mass might not correspond to the location of the poles, (iii) the locations of the $P_{c} (4312)^{+}$ and $P_{c} (4337)^{+}$ might be explained in terms of the $D ˉ^{*} Λ_{c}$ - $D ˉ Σ_{c}$ and $D ˉ^{*} Λ_{c}$ - $D ˉ Σ_{c}^{*}$ coupled channel dynamics. This last option, though not the most probable explanation, is still potentially compatible with the double peak solution of the $P_{cs} (4459)^{0}$ and with what we know of the $P_{c} (4312)^{+}$ . As a byproduct of the previous explorations, we conjecture the existence of a series of anticharmed meson - antitriplet charmed baryon bound states and calculate their masses.
Comments:
19 pages, 5 tables, 1 figure, corresponds with published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2108.05306 [pdf]
EPJC(2022)·33 citations
08
[Submitted on 11 Aug 2021] (cross-list from hep-ph)
Final State Gluon Emission in Deep-Inelastic Scattering at Next-to-Leading Twist
Chathuranga Sirimanna🇺🇸 · Shanshan Cao🇺🇸 · Abhijit Majumder🇺🇸
A detailed reanalysis of the single gluon emission rate at next-to-leading twist is carried out. As was the case in prior efforts, the problem is cast in the framework of deep-inelastic scattering (DIS) of an electron off a large nucleus. The quark produced in the interaction propagates through the remaining nucleus and engenders scattering and gluon radiation, which is calculated in the limit of one re-scattering. This medium induced single gluon emission rate forms the basis of several energy loss calculations in both DIS and heavy-ion collisions. Unlike prior efforts, a complete transverse momentum gradient expansion of the hadronic tensor, including $N_{c}$ suppressed terms, phase terms and finite gluon momentum fraction terms, ignored previously, is carried out. These terms turn out to be surprisingly large. In contrast to prior efforts, the full next-to-leading twist gluon emission kernel is found to be positive definite and slowly increasing with the exchanged transverse momentum. Phenomenological consequences of these new contributions are discussed.
Comments:
24 pages, 26 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2108.05329 [pdf]
PRC(2022)·19 citations

Affiliations

first authorsco-authorsvia INSPIRE