Nuclear Theory·nucl-th

Tuesday·October 19, 2021

15 papers—6 primary·9 cross-listed

01
[Submitted on 16 Oct 2021]
Protonium annihilation densities in a unitary coupled channel model
Emanuel Ydrefors🇧🇷 · Jaume Carbonell🇫🇷
We consider a unitary coupled channel model to describe the low energy proton-antiproton scattering and the lower Coulomb-like protonium states. The existence of deeper quasi-bound states of nuclear nature is found to be a consequence of the experimental data. The properties of these states as well as the protonium annihilation densities are described and the difference with respect to the optical models description are manifested.
Comments:
14 pages
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2110.08628 [pdf]
EPJA(2021)·4 citations
02
[Submitted on 17 Oct 2021]
Hybrid stars with color superconducting cores in an extended FCM model
Daniela Curin🇦🇷 · Ignacio F. Ranea-Sandoval🇦🇷 · Mauro Mariani🇦🇷 · Milva G. Orsaria🇦🇷 · Fridolin Weber🇺🇸
We investigate the influence of repulsive vector interactions and color superconductivity on the structure of neutron stars using an extended version of the field correlator method (FCM) for the description of quark matter. The hybrid equation of state is constructed using the Maxwell description, which assumes a sharp hadron-quark phase transition. The equation of state of hadronic matter is computed for a density-dependent relativistic lagrangian treated in the mean-field approximation, with parameters given by the SW4L nuclear model. This model described the interactions among baryons in terms of $σ, ω, ρ, σ^{*}$ , and $ϕ$ mesons. Quark matter is assumed to be in either the CFL or the 2SC+s color superconducting phase. The possibility of sequential (hadron-quark, quark-quark) transitions in ultra-dense matter is investigated. Observed data related to massive pulsars, gravitational-wave events, and NICER are used to constrain the parameters of the extended FCM model. The successful equations of state are used to explore the mass-radius relationship, radii, and tidal deformabilities of hybrid stars. A special focus lies on investigating consequences that slow or fast conversions of quark-hadron matter have on the stability and the mass-radius relationship of hybrid stars. We find that if slow conversion should occur, a new branch of stable massive stars would exist whose members have radii that are up to 1.5~km smaller than those of conventional neutron stars of the same mass. Such objects could be possible candidates for the stellar high-mass object of the GW190425 binary system.
Comments:
This article has the same content as the one published in Universe 2021, 7(10), 370
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM)
arXiv:
2110.08892 [pdf]
Universe(2021)·12 citations
03
[Submitted on 17 Oct 2021]
Low Density Neutron Star Matter with Quantum Molecular Dynamics: The Role of Vector Interactions
Parit Mehta · Rana Nandi · R. O. Gomes · V. Dexheimer · J. Steinheimer
The effect of isospin-dependent nuclear forces on the inner crust of neutron stars is modeled within the framework of Quantum Molecular Dynamics (QMD). To successfully control the density dependence of the symmetry energy of neutron-star matter below nuclear saturation density, a coupling potential between the $ω$ and $ρ$ meson fields is introduced. This approach is inspired by the baryon density and isospin density-dependent repulsive Skyrme force of asymmetric nuclear matter. In isospin-asymmetric nuclear matter, the system shows nucleation, as nucleons are arranged into shapes resembling nuclear pasta. The dependence of clusterization in the system on the isospin properties is also explored by calculating two-point correlation functions. We show that, as compared to previous results that did not involve the $ω$ - $ρ$ potential, the energy symmetry slope $L$ is successfully controlled by varying the $ω$ - $ρ$ coupling strength. Nevertheless, the effect of changing the slope of the nuclear symmetry energy $L$ on the crust-core transition density does not seem significant. To the knowledge of the authors, This is the first implementation of a $ω$ - $ρ$ coupling in a QMD model for the inner crust of neutron stars.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2110.08916 [pdf]
Universe(2022)·4 citations
04
[Submitted on 18 Oct 2021]
Strange quark matter and proto-strange stars in an equivaparticle model
H. M. Chen🇨🇳 · C. J. Xia🇨🇳 · G. X. Peng🇨🇳
The properties of strange quark matter and the structures of (proto-)strange stars are studied within the framework of an equivparticle model, where a new quark mass scaling and self-consistent thermodynamic treatment are adopted. Our results show that the perturbative interaction has a strong impact on the properties of strange quark matter. It is found that the energy per baryon increases with temperature, while the free energy decreases and eventually becomes negative. At fixed temperatures, the pressure at the minimum free energy per baryon is zero, suggesting that the thermodynamic self-consistency is preserved. Additionally, the sound velocity v in quark matter approaches to the extreme relativistic limit (c/sqrt(3)) as the density increases. By increasing the strengths of confinement parameter D and perturbation parameter C, the tendency for v to approach the extreme relativistic limit at high density is slightly weakened. For (proto-)strange stars, in contrast to the quark mass scalings adopted in previous publications, the new quark mass scaling can accommodate massive proto-strange stars with their maximum mass surpassing twice the solar mass at T = 50 MeV.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2110.09187 [pdf]
CPC(2022)·8 citations
05
[Submitted on 18 Oct 2021]
Importance truncation for the in-medium similarity renormalization group
J. Hoppe · A. Tichai · M. Heinz · K. Hebeler · A. Schwenk
Ab initio nuclear many-body frameworks require extensive computational resources, especially when targeting heavier nuclei. Importance-truncation (IT) techniques allow to significantly reduce the dimensionality of the problem by neglecting unimportant contributions to the solution of the many-body problem. In this work, we apply IT methods to the nonperturbative in-medium similarity renormalization group (IMSRG) approach and investigate the induced errors for ground-state energies in different mass regimes based on different nuclear Hamiltonians. We study various importance measures, which define the IT selection, and identify two measures that perform best, resulting in only small errors to the full IMSRG(2) calculations even for sizable compression ratios. The neglected contributions are accounted for in a perturbative way and serve as an estimate of the IT-induced error. Overall we find that the IT-IMSRG(2) performs well across all systems considered, while the largest compression ratios for a given error can be achieved when using soft Hamiltonians and for large single-particle bases.
Comments:
14 pages, 9 figures, published version
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2110.09390 [pdf]
PRC(2022)·8 citations
06
[Submitted on 18 Oct 2021]
Freezeout properties of different light nuclei at the RHIC Beam Energy Scan
M. Waqas🇨🇳 · G. X. Peng🇨🇳 · Rui-Qin Wang🇨🇳 · Muhammad Ajaz🇵🇰 · Abd Al Karim Haj Ismail🇦🇪
We study the transverse momentum spectra of light nuclei (deuteron, anti-deuteron and triton) produced in Gold-Gold (Au-Au) collisions in different centrality bins by the blast wave model with Tsallis statistics. The model results are in agreement with the experimental data measured by STAR Collaboration in special transverse momentum ranges. We extracted the kinetic freezeout temperature, transverse flow velocity and kinetic freezeout volume. It is observed that kinetic freezeout temperature and transverse flow velocity increases initially, and then saturates from 14.5-39 GeV, while the kinetic freezeout volume increase initially up to 19.6 GeV but saturates from 19.6-39 GeV. This may indicate that the phase transition starts in part volume that ends in the whole volume at 39 GeV and the critical point may exists somewhere in the energy range of 14.5-39 GeV. The present work observed that the kinetic freezeout temperature, transverse flow velocity and kinetic freezeout volume has a decreasing trend from central to peripheral collisions. We found the freezeout volume of triton is smaller than those of deuteron and anti-deuteron, which shows that triton freezeout earlier than that of deuteron and anti-deuteron.
Comments:
21 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2110.09505 [pdf]
Eur.Phys.J.Plus(2021)·19 citations
07
[Submitted on 15 Oct 2021] (cross-list from hep-ph)
Holographic modeling of nuclear matter and neutron stars
Matti Jarvinen🇰🇷
I review holographic models for (dense and cold) nuclear matter, neutron stars, and their mergers. I start by a brief general discussion on current knowledge of cold QCD matter and neutron stars, and go on discussing various approaches to model cold nuclear and quark matter by using gauge/gravity duality, pointing out their strengths and weaknesses. Then I focus on recent results for a complex bottom-up holographic framework (V-QCD), which also takes input from lattice QCD results, effective field theory, and perturbative QCD. Dense nuclear matter is modeled in V-QCD through a homogeneous non-Abelian bulk gauge field. Feasible "hybrid" equations of state for cold nuclear (and quark) matter can be constructed by using traditional methods (e.g., effective field theory) at low densities and the holographic V-QCD model at higher densities. I discuss the constraints from this approach to the properties of the nuclear to quark matter transition as well as to properties of neutron stars. Using such hybrid equations of state as an input for numerical simulations of neutron star mergers, I also derive predictions for the spectrum of produced gravitational waves.
Comments:
Review article published in Eur.Phys.J.C. 58 pages, 24 figures, 2 tables. v2: references and comments added
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2110.08281 [pdf]
EPJC(2022)·87 citations
08
[Submitted on 15 Oct 2021] (cross-list from nucl-ex)
Shapes, Softness and Non-Yrast Collectivity in 186W
V. S. Prasher🇺🇸 · A. J. Mitchell🇺🇸 · C. J. Lister🇺🇸 · P. Chowdhury🇺🇸 · L. Afanasieva🇺🇸 · M. Albers🇺🇸 · C. J. Chiara🇺🇸 · M. P. Carpenter🇺🇸 · D. Cline🇺🇸 · N. D'Olympia🇺🇸 · C. J. Guess🇺🇸 · A. B. Hayes🇺🇸 and 14 other authors
Non-yrast, excited states in neutron-rich $^{186}$ W were populated via inelastic-scattering reactions using beams of $^{136}$ Xe nuclei accelerated to 725 and 800 MeV. Levels populated in the reactions were investigated via particle- $γ$ coincidence techniques using the Gammasphere array of High-Purity Germanium detectors and the compact heavy-ion counter, CHICO2. The $K^{π} = 2^{+}$ ( $γ$ ), $K^{π} = 0^{+}$ and $K^{π} = 2^{-}$ (octupole) rotational side bands were extended to spins $14ℏ$ , $12ℏ$ , and $13ℏ$ , respectively. A staggering pattern observed in the energies of levels in the $K^{π} = 2^{+}$ band was found to be consistent with a potential that gets softer to vibration in the $γ$ degree of freedom with increasing spin. The odd-even staggering of states in the $K^{π} = 2^{-}$ band was found to exhibit a phase opposite to that seen in the $γ$ band; an effect most probably associated with Coriolis coupling to other, unobserved octupole vibrational bands in $^{186}$ W.
Comments:
14 pages, 16 figures
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2110.08347 [pdf]
PRC(2021)·1 citation
09
[Submitted on 15 Oct 2021] (cross-list from nucl-ex)
Measurement of the EMC effect in light and heavy nuclei
J. Arrington🇺🇸 · J. Bane🇺🇸 · A. Daniel🇺🇸 · N. Fomin🇺🇸 · D. Gaskell🇺🇸 · J. Seely🇺🇸 · R. Asaturyan🇦🇲 · F. Benmokhtar🇺🇸 · W. Boeglin🇺🇸 · P. Bosted🇺🇸 · M.H.S. Bukhari🇺🇸 · M.E. Christy🇺🇸 and 45 other authors
Inclusive electron scattering from nuclear targets has been measured to extract the nuclear dependence of the inelastic cross section in Hall C at the Thomas Jefferson National Accelerator facility. Results are presented for 2H, 3He, 4He, 9B, 12C, 63Cu and 197Au at an incident electron beam energy of 5.77 GeV for a range of momentum transfer from Q^2 = 2 to 7 (GeV/c)^2. These data improve the precision of the existing measurements of the EMC effect in the nuclear targets at large x, and allow for more detailed examinations of the A dependence of the EMC effect.
Comments:
28 pages, 23 figures, archival paper for Jefferson Lab experiment E03-103
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2110.08399 [pdf]
PRC(2021)·36 citations
10
[Submitted on 16 Oct 2021] (cross-list from nucl-ex)
Insight from the elliptic flow of identified hadrons measured in relativistic heavy-ion collisions
Prabhupada Dixit🇮🇳 · Md. Nasim🇮🇳
In this paper, we have discussed the transverse momentum dependence of elliptic flow measured in relativistic heavy-ion collisions. The transverse momentum dependence of the number of constituent quarks ( $n_{q}$ ) scaled $v_{2}$ is obtained for all the measured identified hadrons. The $n_{q}$ scaled $ϕ$ $v_{2}$ is found to be similar to $n_{q}$ scaled $Ω$ $v_{2}$ . This indicates that both $ϕ$ and $Ω$ are produced through quark recombination at RHIC energies. We also find $n_{q}$ scaled proton $v_{2}$ ( $v_{2}$ of light quarks) is higher than $n_{q}$ scaled $ϕ$ and $Ω$ $v_{2}$ ( $v_{2}$ of strange quarks) at $p_{T} / n_{q}$ $<$ 1.0 GeV/c. This can be explained by considering quark $v_{2}$ is proportional to its transverse kinetic energy considering mass of deconfined light and strange quarks equal to $\sim$ 4 MeV and $\sim$ 140 MeV, respectively.
Comments:
8 pages, 6 figures
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2110.08573 [pdf]
IJMPE(2022)·0 citations
11
[Submitted on 17 Oct 2021] (cross-list from hep-ph)
Nature of $X (2370)$
Xiang Sun🇨🇳 · Ling-Yun Dai🇨🇳 · Shi-Qing Kuang🇨🇳 · Wen Qin🇨🇳 · A.P. Szczepaniak🇺🇸
We address the nature of the $X (2370)$ resonance observed in the $J / ψ$ radiative decays, $J / ψ \to γ K^{+} K^{-} η^{'}$ , $J / ψ \to γ K_{S} K_{S} η^{'}$ and $J / ψ \to γ π^{+} π^{-} η^{'}$ . By studying the invariant mass spectra we confirm that decays of the $X (2370)$ into three pseudo-scalars are well described by an effective chiral Lagrangian. We extract the branching ratio of $J / ψ \to X (2370) γ$ and show that it is an order of magnitude larger compared to the glueball production rate predicted by lattice QCD. This indicates that $X (2370)$ is not likely to be a glueball candidate.
Comments:
5 pages, 2 figures, to be the same as the published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2110.08827 [pdf]
PRD(2022)·7 citations
12
[Submitted on 18 Oct 2021] (cross-list from nucl-ex)
The cross-section measurement for the $^{3} H (e, e^{'} K^{+}) nn Λ$ reaction
K. N. Suzuki · T. Gogami · B. Pandey · K. Itabashi · S. Nagao · K. Okuyama · S. N. Nakamura · L. Tang · D. Abrams · T. Akiyama · D. Androic · K. Aniol and 71 other authors
The small binding energy of the hypertrition leads to predictions of non-existence of bound hypernuclei for isotriplet three-body systems such as $nn Λ$ . However, invariant mass spectroscopy at GSI has reported events that may be interpreted as the bound $nn Λ$ state. The $nn Λ$ state was sought by missing-mass spectroscopy via the $(e, e^{'} K^{+})$ reaction at Jefferson Lab's experimental Hall A. The present experiment has higher sensitivity to the $nn Λ$ -state investigation in terms of better precision by a factor of about three. The analysis shown in this article focuses on the derivation of the reaction cross-section for the $^{3} H (γ^{*}, K^{+}) X$ reaction. Events that were detected in an acceptance, where a Monte Carlo simulation could reproduce the data well ( $∣ δ p / p ∣ < 4%$ ), were analyzed to minimize the systematic uncertainty. No significant structures were observed with the acceptance cuts, and the upper limits of the production cross-section of the $nn Λ$ state were obtained to be $21$ and $31 nb/sr$ at the $90%$ confidence level when theoretical predictions of $(- B_{Λ}, Γ) = (0.25, 0.8)$ and $(0.55, 4.7)$ MeV, respectively, were assumed. The cross-section result provides valuable information for examining the existence of $nn Λ$ .
Comments:
27 pages, 12 figures
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2110.09104 [pdf]
PTEP(2022)·13 citations
13
[Submitted on 18 Oct 2021] (cross-list from hep-ph)
Long-range neutrinoless double beta decay mechanisms
Jenni Kotila🇫🇮 · Jacopo Ferretti🇫🇮 · Francesco Iachello🇺🇸
Understanding the origin of lepton number violation is one of the fundamental questions in particle physics today. Neutrinoless double beta decay provides a way in which this violation can be tested. In this article, we derive the form of hadronic and leptonic matrix elements for all possible long-range mechanisms of neutrinoless double beta decay. With these, we calculate the numerical values of the nuclear matrix elements (NME) and phase space factors (PSF) by making use of the interacting boson model of the nucleus (IBM-2) for NMEs and of exact Dirac wave functions for the PSFs. We show that:\ (I) lepton number violation can occur even with zero (or very small) neutrino mass and (II) the angular correlations of the emitted electrons can distinguish between different models of non-standard (NS) mechanisms. We set limits on the coupling constants of some NS models, in particular Left-Right models and SUSY models.
Comments:
60 pages, 8 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2110.09141 [pdf]
16 citations
14
[Submitted on 18 Oct 2021] (cross-list from hep-ph)
Strangelets at finite temperature in an equivparticle model
H. M. Chen🇨🇳 · C. J. Xia🇨🇳 · G. X. Peng🇨🇳
The properties of strangelets at finite temperature are studied within the framework of an equivparticle model, where a new quark mass scaling and self-consistent thermodynamic treatment are adopted. The effects of finite volume and Coulomb energy are taken into account. Our results show that the temperature T, baryon number A and perturbation interactions have strong influences on the properties of strangelets. It is found that the energy per baryon M/A and charge-to-mass ratio fz decrease with baryon number A, while the mechanically stable radius R and strangeness per baryon fs are increasing. For a strangelet with a fixed baryon number, we note that as temperature T increases the quantites M/A, R, and fs are increasing while fz is decreasing. The effects of confinement and perturbative interactions are investigated as well by readjusting the corresponding parameters.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2110.09194 [pdf]
PRD(2022)·16 citations
15
[Submitted on 18 Oct 2021] (cross-list from hep-ph)
Accessing the pion 3D structure at US and China Electron-Ion Colliders
J. M. Morgado Chávez🇪🇸 · V. Bertone🇫🇷 · F. De Soto🇪🇸 · M. Defurne🇫🇷 · C. Mezrag🇫🇷 · H. Moutarde🇫🇷 · J. Rodríguez-Quintero🇪🇸 · J. Segovia🇪🇸
We present in this letter the first systematic feasibility study of accessing generalised parton distributions of the pion at an electron-ion collider through deeply virtual Compton scattering at next-to-leading order. It relies on a state-of-the-art model, able to fulfil by construction all the theoretical constraints imposed on generalised parton distributions. Strikingly, our analysis shows that quarks and gluons interfere destructively and that gluon dominance could be spotted by a sign change of the DVCS beam spin asymmetry.
Comments:
7 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2110.09462 [pdf]
PRL(2022)·55 citations

Affiliations

first authorsco-authorsvia INSPIRE