Nuclear Theory·nucl-th

Thursday·March 28, 2024

11 papers—4 primary·7 cross-listed

01
[Submitted on 27 Mar 2024]
Trineutron resonances in the SS-HORSE-NCSM approach
I. A. Mazur · M. K. Efimenko · A. I. Mazur · I. J. Shin · V. A. Kulikov · A. M. Shirokov · J. P. Vary
The SS-HORSE-NCSM method is generalized to the case of democratic decay into an odd number of fragments. This method is applied to the search for resonances in three-neutron system (trineutron) using ab initio No-Core Shell Model calculations with realistic nucleon-nucleon potentials. The $3/ 2^{-}$ and $1/ 2^{-}$ strongly overlapping resonances are predicted when softened $N N$ interactions are used and are preferred over the case where bare $N N$ interactions of the chiral effective field theory are used with no resonance obtained.
Comments:
7 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2403.18232 [pdf]
PRC(2024)·6 citations
02
[Submitted on 27 Mar 2024]
Nuclear shape evolution of neutron-deficient Au and kink structure of Pb isotopes
Myeong-Hwan Mun · Eunja Ha · Yong-Beom Choi · Myung-Ki Cheoun
Recent experiments using advanced laser spectroscopy technique revealed that the charge radii of neutron-deficient gold (Au) isotopes exhibit significant changes in ground state deformation: odd-even shape staggering in the $N = 98 \sim 100$ region and abrupt change of charge radii from $N =$ 108. In this study, we examine the abnormal shape evolution of the nuclear charge radii. To understand the nuclear structure underlying this phenomenon, we exploit the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc). The significant change in mean-squared charge radii ( $δ < r^{2} >$ ) turns out to originate from nuclear shape transitions between prolate deformation and small oblate deformation due to the shape coexistence possibility. We elucidate the nuclear shape evolution by analyzing the evolution of occupation probability for single-particle states. In addition, the abrupt kink structure in the nuclear charge radius of lead (Pb) isotopes near the $N =$ 126 shell is also investigated and reproduced quite well.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2403.18377 [pdf]
PRC(2024)·8 citations
03
[Submitted on 27 Mar 2024]
Uncertainty quantification in $(p, n)$ reactions
A. J. Smith · C. Hebborn · F. M. Nunes · R. G. T. Zegers
Charge-exchange reactions are versatile probes for nuclear structure. In particular, when populating isobaric analog states, these reactions are used to study isovector nuclear densities and neutron skins. The quality of the information extracted from charge-exchange data depends on the accuracy of the reaction models and their inputs; this work addresses these two points. First, we quantify the uncertainties due to effective nucleon-nucleus interactions by propagating the parameter posterior distributions of the recent global optical model KDUQ [1] to $(p, n)$ reaction observables populating the isobaric analogue state, at beam energies in the range of $25 - 160$ MeV. Our analysis, focusing on $^{48}$ Ca, shows that the total parametric uncertainties on the cross sections are around 60-100%. The source of this uncertainty is mainly the transition operator as the uncertainties from the distorted waves alone are less than about 15%. Second, we perform a comparison between two- and three-body models that both describe the dynamics of the reaction within the DWBA. The predictions from these two models are similar and generally agree with the available data, suggesting that 1-step DWBA is sufficient to describe the reaction process. Only at a beam energy of 25 MeV there are possibly signs that a 1-step assumption is not fully correct. This work provides motivation for the quantification of uncertainties associated with the transition operator in three-body model. It also suggests that further constraint of the optical potential parameters is needed for increased model precision.
Comments:
7 pages, 4 figures, Published in Phys. Rev. C 110 034602 (2024)
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2403.18629 [pdf]
PRC(2024)·11 citations
04
[Submitted on 27 Mar 2024]
$p Λ ˉ$ final-state interaction in the reactions $e^{+} e^{-} \to K^{-} p Λ ˉ$ and $J / ψ \to K^{-} p Λ ˉ$
J. Haidenbauer🇩🇪 · U.-G. Meißner🇩🇪
Near-threshold $p Λ ˉ$ mass spectra for the reactions $e^{+} e^{-} \to K^{-} p Λ ˉ$ and $J / ψ \to K^{-} p Λ ˉ$ are investigated with an emphasis on the role played by the interaction in the $p Λ ˉ$ system. As guideline for the $p Λ ˉ$ interaction a variety of $Λ Λ ˉ$ potential models is considered that have been established in the analysis of data on $p p ˉ \to Λ Λ ˉ$ in the past. Arguments why the properties of the $p Λ ˉ$ and $Λ Λ ˉ$ interactions can be expected to be very similar are provided. It is shown that the near-threshold enhancement in the invariant mass observed for the $e^{+} e^{-}$ reaction can be reproduced quantitatively by the assumed $p Λ ˉ$ final-state interaction in the partial wave suggested by an amplitude analysis of the experiment. The effect of the $p Λ ˉ$ final-state interaction in other decays is explored, including the recently measured reactions $B^{-} \to J / ψ p ˉ Λ$ and $B^{+} \to J / ψ p Λ ˉ$ . It is found that the final-state interaction improves the description of the measured invariant mass near threshold in most cases.
Comments:
9 pages, 11 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2403.18706 [pdf]
EPJA(2024)·8 citations
05
[Submitted on 26 Mar 2024] (cross-list from hep-ph)
Pressure and speed of sound in two-flavor color-superconducting quark matter at next-to-leading order
Andreas Geißel🇩🇪 · Tyler Gorda🇩🇪 · Jens Braun🇩🇪
Deconfined quark matter at asymptotically high densities is weakly coupled, due to the asymptotic freedom of Quantum Chromodynamics. In this weak-coupling regime, bulk thermodynamic properties of quark matter, assuming a trivial ground state, are currently known to partial next-to-next-to-next-to-leading order. However, the ground state at high densities is expected to be a color superconductor, in which the excitation spectrum of (at least some) quarks exhibit a gap with a non-perturbative dependence on the strong coupling. In this work, we calculate the thermodynamic properties of color-superconducting quark matter at high densities and zero temperature at next-to-leading order (NLO) in the coupling in the presence of a finite gap. We work in the limit of two massless quark flavors, which corresponds to deconfined symmetric nuclear matter, and further assume that the gap is small compared to the quark chemical potential. In these limits, we find that the NLO corrections to the pressure and speed of sound are comparable in size to the leading-order effects of the gap, and further increase both quantities above their values for non-superconducting quark matter. We also provide a parameterization of the NLO speed of sound to guide phenomenology in the high-density region, and we furthermore comment on whether our findings should be expected to extend to the case of three-flavor quark matter of relevance to neutron stars.
Comments:
20 pages, 9 figures, 1 table
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2403.18010 [pdf]
PRD(2024)·32 citations
06
[Submitted on 27 Mar 2024] (cross-list from hep-ph)
Parity doublet model for baryon octets: ground states saturated by good diquarks and the role of bad diquarks for excited states
Bikai Gao🇯🇵 · Toru Kojo🇯🇵 · Masayasu Harada🇯🇵
Parity doublet model is an effective chiral model that includes the chiral variant and invariant masses of baryons. The chiral invariant mass has large impacts on the density dependence of models which can be constrained by neutron star observations. In the previous work, models of two-flavors have been considered up to a few times nuclear saturation density, but in such dense region it is also necessary to consider hyperons. With the chiral invariant masses baryons can stay massive in extreme environments (e.g., neutron stars) where the chiral symmetry restoration takes place. In this work, we generalize the previous $\mbox S U (2)_{L} \times \mbox S U (2)_{R}$ parity models of nucleons to $\mbox S U (3)_{L} \times \mbox S U (3)_{R}$ models of the baryon octet, within the linear realization of the chiral symmetry. The major problem in constructing such models has been too many candidates for the chiral representations of baryons. Motivated by the concepts of diquarks and the mended symmetry, we choose the $(3_{L}, 3 ˉ_{R}) + (3 ˉ_{L}, 3_{R})$ , $(3_{L}, 6_{R}) + (6_{L}, 3_{R})$ and $(1_{L}, 8_{R}) + (8_{L}, 1_{R})$ representations and use quark diagrams to constrain the possible types of Yukawa interactions. The masses of the baryon octets for positive and negative baryons up to the first excitations are successfully reproduced. As expected from the diquark considerations, the ground state baryons are well dominated by $(3_{L}, 3 ˉ_{R}) + (3 ˉ_{L}, 3_{R})$ and $(1_{L}, 8_{R}) + (8_{L}, 1_{R})$ representations, while the excited states require $(3_{L}, 6_{R}) + (6_{L}, 3_{R})$ representations. Important applications of our model are the chiral restoration for strange quarks at large density and the continuity of diquarks from hadronic to quark matter. We also address the problem of large Yukawa couplings which are enhanced in three-flavor construction.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2403.18214 [pdf]
PRD(2024)·17 citations
07
[Submitted on 27 Mar 2024] (cross-list from hep-ph)
A Deep Learning Framework for Disentangling Triangle Singularity and Pole-Based Enhancements
Darwin Alexander O. Co🇵🇭 · Vince Angelo A. Chavez🇵🇭 · Denny Lane B. Sombillo🇵🇭
Enhancements in the invariant mass distribution or scattering cross-section are usually associated with resonances. However, the nature of exotic signals found near hadron-hadron thresholds remain a puzzle today due to the presence of experimental uncertainties. In fact, a purely kinematical triangle diagram is also capable of producing similar structures, but do not correspond to any unstable quantum state. In this paper, we report for the first time, that a deep neural network can be trained to distinguish triangle singularity from pole-based enhancements with a reasonably high accuracy of discrimination between the two seemingly identical line shapes. We also identify the type of triangle enhancement that can be misidentified as a dynamic pole structure. We apply our method to confirm that the $P_{ψ}^{N} (4312)^{+}$ state is not due to a triangle singularity, but is more consistent with a pole-based interpretation, as determined solely through pure line-shape analysis. Lastly, we explain how our method can be used as a model-selection framework useful in studying other exotic hadron candidates.
Comments:
17 pages, 11 figures; accepted in Physical Review D
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2403.18265 [pdf]
PRD(2024)·15 citations
08
[Submitted on 27 Mar 2024] (cross-list from hep-ph)
Role of hidden-color components in the tetraquark mixing model
Hungchong Kim🇰🇷 · K.S.Kim🇰🇷
Multiquarks can have two-hadron components and hidden-color components in their wave functions. The presence of two-hadron components in multiquarks introduces a potential source of confusion, particularly with respect to their resemblance to hadronic molecules. On the other hand, hidden-color components are essential for distinguishing between multiquarks and hadronic molecules. In this work, we study the hidden-color components in the wave functions of the tetraquark mixing model, a model that has been proposed as a suitable framework for describing the properties of two nonets in the $J^{P} = 0^{+}$ channel: the light nonet [ $a_{0} (980)$ , $K_{0}^{*} (700)$ , $f_{0} (500)$ , $f_{0} (980)$ ] and the heavy nonet [ $a_{0} (1450)$ , $K_{0}^{*} (1430)$ , $f_{0} (1370)$ , $f_{0} (1500)$ ]. Our analysis reveals a substantial presence of hidden-color components within the tetraquark wave functions. To elucidate the impact of hidden-color components on physical quantities, we conduct computations of the hyperfine masses, $⟨ V_{C S} ⟩$ , for the two nonets, considering scenarios involving only the two-meson components and those incorporating the hidden-color components. We demonstrate that the hidden-color components constitute an important part of the hyperfine masses, such that the mass difference formula, $Δ M \approx Δ ⟨ V_{C S} ⟩$ , which has been successful for the two nonets, cannot be achieved without the hidden-color contributions. This can provide another evidence supporting the tetraquark nature of the two nonets.
Comments:
10 pages, no figure. The version accepted for publication in EPJC
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2403.18411 [pdf]
EPJC(2024)·5 citations
09
[Submitted on 27 Mar 2024] (cross-list from hep-ph)
The effect of cutoff dependence on heavy quark spin symmetry partners
Duygu Yıldırım🇹🇷
Hadron spectroscopy is revealed by observing heavy resonances. Among various explanations of the internal structure of these hadronic states, hadronic molecules play a unique role. For hadronic molecules, which are associated with meson-meson or meson-baryon interactions, the $Λ$ cutoff is a significant factor in determining the composite states' binding energies and overall properties. The cutoff becomes important when it comes to the location of hadronic molecules' masses because it influences the predictions. From this perspective, in the light of cutoff dependency, heavy quark spin partners of near-threshold the $χ_{c 0} (3915)$ , $χ_{c 1} (3872)$ , $P_{c} (4440)$ , and $P_{c} (4457)$ resonances, which are considered as hadronic molecules, are examined.
Comments:
4 pages, 2 tables, accepted by MPL A
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2403.18633 [pdf]
Mod.Phys.Lett.A(2024)·0 citations
10
[Submitted on 27 Mar 2024] (cross-list from gr-qc)
Effects of Dark Matter on $f$ -mode oscillations of Neutron Stars
Swarnim Shirke🇮🇳 · Bikram Keshari Pradhan🇮🇳 · Debarati Chatterjee🇮🇳 · Laura Sagunski🇩🇪 · Jürgen Schaffner-Bielich🇩🇪
The effect of dark matter (DM) on $f$ -mode oscillations in DM admixed neutron stars (NSs) is investigated in a comprehensive analysis with particular attention to the role of the nuclear equation of state. Hadronic matter is modeled by the relativistic mean field model and the DM model is based on the neutron decay anomaly. The non-radial $f$ -mode oscillations for such DM admixed NS are studied in a full general relativistic framework. We investigate the impact of DM, DM self-interaction, and DM fraction on the $f$ -mode characteristics. We derive relations encoding the effect of DM on $f$ -mode parameters. We then perform a systematic study by varying all the model parameters within their known uncertainty range and obtain a universal relation for the DM fraction based on the total mass of the star and DM self-interaction strength. We also perform a correlation study among model parameters, NS observables, in particular, $f$ -mode parameters. Finally, we check the $f$ -mode universal relations (URs) for the case of DM admixed NSs and demonstrate the existence of a degeneracy between purely hadronic NSs and DM admixed NSs.
Comments:
27 pages, 22 figures, 5 tables. Published in PRD. Accepted version of the manuscript
Subjects:
General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2403.18740 [pdf]
PRD(2024)·37 citations
11
[Submitted on 27 Mar 2024] (cross-list from gr-qc)
Measuring the Lense-Thirring Orbital Precession and the Neutron Star Moment of Inertia with Pulsars
Huanchen Hu · Paulo C. C. Freire
Neutron stars (NSs) are compact objects that host the densest forms of matter in the observable universe, providing unique opportunities to study the behaviour of matter at extreme densities. While precision measurements of NS masses through pulsar timing have imposed effective constraints on the equation of state (EoS) of dense matter, accurately determining the radius or moment of inertia (MoI) of a NS remains a major challenge. This article presents a detailed review on measuring the Lense-Thirring (LT) precession effect in the orbit of binary pulsars, which would give access to the MoI of NSs and offer further constraints on the EoS. We discuss the suitability of certain classes of binary pulsars for measuring the LT precession from the perspective of binary star evolution, and highlight five pulsars that exhibit properties promising to realise these goals in the near future. Finally, discoveries of compact binaries with shorter orbital periods hold the potential to greatly enhance measurements of the MoI of NSs. The MoI measurements of binary pulsars are pivotal to advancing our understanding of matter at supranuclear densities as well as improving the precision of gravity tests, such as the orbital decay due to gravitational wave emission and of tests of alternative gravity theories.
Comments:
Corrections to the title and references in accordance with the published version
Subjects:
General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2403.18785 [pdf]
Universe(2024)·16 citations

Affiliations

first authorsco-authorsvia INSPIRE