Nuclear Theory·nucl-th

Thursday·April 21, 2022

7 papers—1 primary·6 cross-listed

01
[Submitted on 20 Apr 2022]
Pion-nucleon sigma term $σ_{π N}$ and deeply bound pionic atoms
Natsumi Ikeno🇯🇵 · Takahiro Nishi🇯🇵 · Kenta Itahashi🇯🇵 · Naoko Nose-Togawa🇯🇵 · Akari Tani🇯🇵 · Satoru Hirenzaki🇯🇵
We investigate the possibility to determine the value of the pion-nucleon sigma term $σ_{π N}$ precisely by the experimental observables of the deeply bound pionic atoms. We discuss the sensitivity of the observables to $σ_{π N}$ and take into account the typical errors of the up-to-date experiments of the deeply bound pionic atoms. We find that the gap of the binding energies and the width of the deeply bound pionic states are good observables for the $σ_{π N}$ value determination by the experimental data. We also discuss the expected difficulties for the accurate determination of the value of $σ_{π N}$ due to the correlation between the $σ$ term and the potential parameter in the pion-nucleus optical potential.
Comments:
14 pages, 8 figures, 3 tables, v2: title changed, discussions on parameter correlations added, updates of some numerical results and figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2204.09211 [pdf]
PTEP(2023)·7 citations
02
[Submitted on 20 Apr 2022] (cross-list from hep-ph)
Cumulants of the chiral order parameter at lower RHIC energies
Christoph Herold🇹🇭 · Ayut Limphirat🇹🇭 · Poramin Saikham🇹🇭 · Marlene Nahrgang🇫🇷
We study cumulants of the chiral order parameter as function of beam energy as a possible signal for the presence of a critical end point and first-order phase transition in the QCD phase diagram. We model the expansion of a heavy-ion collision by a fluid dynamic expansion coupled to the explicit propagation of the chiral order parameter sigma via a Langevin equation. We evolve the medium until a parametrized freeze-out condition is met where we calculate event-by-event fluctuations and cumulants of sigma which are expected to follow the trend of net-proton number cumulants. We emphasize the role of a nonequilibrium first-order phase transition: The presence of an unstable phase causes the well-known bending of the trajectories in the space of temperature and baryochemical potential. For these cases at lower beam energies, the system crosses the freeze-out line more than once, allowing us to calculate a range of cumulants for each initial condition which are overall enhanced for the second hit of the freeze-out line. We thus find not only the critical end point but also the phase transition of the underlying model clearly reflected in the cumulants. The impact of volume fluctuations is demonstrated to play a measurable role for fluid dynamical evolutions that last significantly long.
Comments:
14 pages, 4 figures, ICNFP 2021. arXiv admin note: text overlap with arXiv:2204.00286
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2204.09217 [pdf]
Phys.Scripta(2022)·1 citation
03
[Submitted on 20 Apr 2022] (cross-list from hep-ph)
Heavy-Quark Diffusion in the Quark-Gluon Plasma
Min He🇨🇳 · Hendrik van Hees🇩🇪 · Ralf Rapp🇺🇸
The diffusion of heavy quarks through the quark-gluon plasma (QGP) as produced in high-energy heavy-ion collisions has long been recognized as an excellent probe of its transport properties. In addition, the experimentally observed heavy-flavor hadrons carry valuable information about the hadronization process of the transported quarks. Here we review recent progress in the theoretical developments of heavy-quark interactions in the QGP and how they relate to the nonperturbative hadronization process, and discuss the recent status of the pertinent phenomenology in heavy-ion collisions at the RHIC and the LHC. The interactions of heavy quarks in the QGP also constitute a central building block in the description of the heavy quarkonia which controls their transport parameters as well. We will thus focus on theoretical approaches that aim for a unified description of open and hidden heavy-flavor particles in medium, and discuss how they can be constrained by lattice QCD "data" and utilized to deduce fundamental properties of the microscopic interactions and emerging spectral properties of the strongly coupled QGP.
Comments:
45 pages, 27 figures, Review article for Progress in Particle and Nuclear Physics
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2204.09299 [pdf]
PPNP(2023)·110 citations
04
[Submitted on 20 Apr 2022] (cross-list from hep-ph)
Study of $N (1520)$ and $N (1535)$ structures via $γ^{*} p \to N^{*}$ transitions
A. Kaewsnod🇹🇭 · K. Xu🇹🇭 · Z. Zhao🇹🇭 · X. Y. Liu🇹🇭 · S. Srisuphaphon🇹🇭 · A. Limphirat🇹🇭 · Y. Yan🇹🇭
The helicity amplitudes of the $N (1520)$ and $N (1535)$ resonances in the $γ^{*} p \to N^{*}$ electromagnetic transition are studied in the constituent quark model using the impulse approximation, with the proton and resonances assumed to be in three-quark configurations. The comparison of theoretical results and experimental data on the helicity amplitudes $A_{1/2}$ , $A_{3/2}$ , and $S_{1/2}$ indicates that the $N (1520)$ and $N (1535)$ resonances are primarily composed of three-quark $L = 1$ states but may contain additional components. However, it is improbable that contributions from meson clouds will be dominant at low $Q^{2}$ .
Comments:
6 pages, 3 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2204.09528 [pdf]
EPJA(2022)·4 citations
05
[Submitted on 20 Apr 2022] (cross-list from nucl-ex)
Summit of the N=40 Island of Inversion: precision mass measurements and ab initio calculations of neutron-rich chromium isotopes
R. Silwal🇨🇦 · C. Andreoiu🇨🇦 · B. Ashrafkhani🇨🇦 · J. Bergmann🇩🇪 · T. Brunner🇨🇦 · J. Cardona🇨🇦 · K. Dietrich🇨🇦 · E. Dunling🇨🇦 · G. Gwinner🇨🇦 · Z. Hockenbery🇨🇦 · J. D. Holt🇨🇦 · C. Izzo🇨🇦 and 15 other authors
Mass measurements continue to provide invaluable information for elucidating nuclear structure and scenarios of astrophysical interest. The transition region between the $Z = 20$ and $28$ proton shell closures is particularly interesting due to the onset and evolution of nuclear deformation as nuclei become more neutron rich. This provides a critical testing ground for emerging ab-initio nuclear structure models. Here, we present high-precision mass measurements of neutron-rich chromium isotopes using the sensitive electrostatic Multiple-Reflection Time-Of-Flight Mass Spectrometer (MR-TOF-MS) at TRIUMF's Ion Trap for Atomic and Nuclear Science (TITAN) facility. Our high-precision mass measurements of $^{59, 61 - 63}$ Cr confirm previous results, and the improved precision in measurements of $^{64 - 65}$ Cr refine the mass surface beyond N=40. With the ab initio in-medium similarity renormalization group, we examine the trends in collectivity in chromium isotopes and give a complete picture of the N=40 island of inversion from calcium to nickel.
Comments:
12 pages, 7 figures
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2204.09566 [pdf]
PLB(2022)·22 citations
06
[Submitted on 20 Apr 2022] (cross-list from hep-ph)
Majorana neutrino mass constraints in the landscape of nuclear matrix elements
Eligio Lisi🇮🇹 · Antonio Marrone🇮🇹
We discuss up-to-date constraints on the Majorana neutrino mass $m_{β β}$ from neutrinoless double beta decay ( $0 ν β β$ ) searches in experiments using different isotopes: KamLAND-Zen and EXO ( $^{136}$ Xe), GERDA and MAJORANA ( $^{76}$ Ge) and CUORE ( $^{130}$ Te). Best fits and upper bounds on $m_{β β}$ are explored in the general landscape of nuclear matrix elements (NME), as well as for specific NME values obtained in representative nuclear models. By approximating the likelihood of $0 ν β β$ signals through quadratic forms, the analysis of separate and combined isotope data becomes exceedingly simple, and allows to clarify various aspects of multi-isotope data combinations. In particular, we analyze the relative impact of different data in setting upper bounds on $m_{β β}$ , as well as the conditions leading to nonzero $m_{β β}$ at best fit, for variable values of the NMEs. Detailed results on $m_{β β}$ from various combinations of data are reported in graphical and numerical form. Implications for future $0 ν β β$ data analyses and NME calculations are briefly discussed.
Comments:
Minor clarifications and additions in the text. Matches published version, Phys. Rev. D 106 (2022) 1, 013009
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2204.09569 [pdf]
PRD(2022)·13 citations
07
[Submitted on 20 Apr 2022] (cross-list from hep-ph)
Collective modes of gluons in an anisotropic thermo-magnetic medium
Bithika Karmakar🇷🇸 · Ritesh Ghosh🇮🇳 · Arghya Mukherjee🇮🇳
We study the collective modes of gluons in an anisotropic thermal medium in the presence of a constant background magnetic field using the hard-thermal loop (HTL) perturbation theory. The momentum space anisotropy of the medium has been incorporated through the generalized $‘$ Romatschke-Strickland' form of the distribution function, whereas, the magnetic modification arising from the quark loop contribution has been taken into account in the lowest Landau level approximation. We consider two special cases: (i) a spheroidal anisotropy with the anisotropy vector orthogonal to the external magnetic field and (ii) an ellipsoidal anisotropy with two mutually orthogonal vectors describing aniostropies along and orthogonal to the field direction. The general structure of the polarization tensor in both cases are equivalent and consists of six independent basis tensors. We find that the introduction of momentum anisotropy ingrains azimuthal angular dependence in the thermo-magnetic collective modes. Our study suggests that the presence of a strong background magnetic field can significantly reduce the growth rate of the unstable modes which may have important implications in the equilibration of magnetized quark-gluon plasma.
Comments:
17 pages, 7 figures, Accepted in Physical Review D
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2204.09646 [pdf]
PRD(2022)·9 citations

Affiliations

first authorsco-authorsvia INSPIRE

Pion-nucleon sigma term σπN​ and deeply bound pionic atoms

Cumulants of the chiral order parameter at lower RHIC energies

Heavy-Quark Diffusion in the Quark-Gluon Plasma

Study of N(1520) and N(1535) structures via γ∗p→N∗ transitions

Summit of the N=40 Island of Inversion: precision mass measurements and ab initio calculations of neutron-rich chromium isotopes

Majorana neutrino mass constraints in the landscape of nuclear matrix elements

Collective modes of gluons in an anisotropic thermo-magnetic medium

Affiliations

Pion-nucleon sigma term $σ_{π N}$ and deeply bound pionic atoms

Study of $N (1520)$ and $N (1535)$ structures via $γ^{} p \to N^{}$ transitions