Nuclear Theory·nucl-th

Wednesday·April 10, 2024

13 papers—5 primary·8 cross-listed

01
Equation of State of Hot Neutron Star Matter using Finite Range Simple Effective Interaction
T. R. Routray🇮🇳 · S. Sahoo🇮🇳 · X. Viñas🇪🇸 · D. N. Basu🇮🇳 · M. Centelles🇪🇸
The equation of state of hot neutron star matter of n+p+e+ $μ$ composition in $β$ -equilibrium is studied for both neutrino-free isothermal and neutrino-trapped isentropic conditions, using the formalism where the thermal evolution is built upon its zero-temperature predictions in a self-consistent manner. The accuracy of the parabolic approximation, often used in the finite temperature calculation of hot neutron star matter, is verified by comparing with the results obtained from the exact evaluation in the neutrino-free neutron star matter. The equation of state of neutrino-trapped isentropic matter at low entropic condition, relevant to the core-collapsing supernovae, is formulated. In the isentropic matter, the particle fractions and equation of state have marginal variance as entropy per particle varies between 1 to 3 (in the unit of k $_{B}$ ), but the temperature profile shows marked variation. The isentropes are found to be much less sensitive to the nuclear matter incompressibility, but have a large dependence on the slope parameter L. The bulk properties of the neutron stars predicted by the isentropic equation of state for different entropy are calculated. A model calculation for the early stage evolution of the protoneutron star to neutron star configuration is also given.
nucl-thastro-ph.HEJ.Phys.G(2024)·8 citations
02
Shape transition and coexistence in Te isotopes studied with the quadrupole collective Hamiltonian based on a relativistic energy density functional
K. Suzuki · K. Nomura
Evolution and coexistence of shape and the related spectroscopic properties of even-even Te isotopes are investigated within the quadrupole collective model that is based on the nuclear density functional theory. By means of the constrained self-consistent mean-field calculations performed within the relativistic Hartree-Bogoliubov method with a choice of the energy density functional and pairing interaction, the deformation-dependent mass parameters and moments of inertia as well as collective potential of the triaxial quadrupole collective Hamiltonian are completely determined. The collective model produces for the near mid-shell nuclei, e.g., $^{116}$ Te and $^{118}$ Te, the low-energy $0_{2}^{+}$ state, which can be interpreted as the intruder state originating from the strongly deformed prolate minimum in the potential energy surface, along with the $0_{1}^{+}$ ground state that is attributed to the normal state based on a weakly oblate deformed global minimum. The collective model calculation suggests a parabolic behavior of the $0_{2}^{+}$ energy level near the neutron mid-shell $N = 66$ , as observed experimentally. Sensitivities of the calculated low-energy spectra to the pairing strength and collective mass parameters are analyzed.
nucl-thnucl-exPRC(2024)·4 citations
03
Variational Optimization for Constructing Inverse Potentials of Proton-Proton Scattering: A Phase Function Method Study
Lalit Kumar · Arushi Sharma · Anil Khachi · Ayushi Awasthi · O. S. K. S. Sastri
Background: The phase-shift analysis for proton-proton scattering has been studied by various research groups using the realistic potentials to be comprised of various internal interactions based on an exchange of pions and mesons, involving a large number of parameters. Purpose: The goal of the research is to construct inverse potentials for various l-channels of proton-proton (pp) elastic scattering using the 3-parameter Morse function in combination with atomic Hulthen by utilizing the phase function method and variational optimization technique. Methodology: The implementation of variational optimization begins with randomly assigning initial values to the Morse model parameters. Utilizing the Morse + Hulthen potential as input, the phase equations for various l-channels are numerically solved using the RK-5 method for obtaining the simulated Scattering Phase Shift (SPS). Mean Squared error between simulated and expected SPS has been chosen as the cost function. Variational optimization proceeds iteratively by adjusting potential parameters and re-evaluating the cost function until convergence is achieved. Results: All the obtained scattering phase shifts for various l-channels have been found to converge to a mean squared error <= 0.3. The computed cross-sections matched the experimental ones to less than 1% for energies up to 25 MeV. The scattering parameters are also found to closely match the experimental data. Conclusion: The inverse potentials constructed for various l-channels using Morse + atomic Hulthen are on par with the currently available high-precision realistic potentials.
nucl-thIndian J.Phys.(2026)·0 citations
04
From chiral EFT to perturbative QCD: a Bayesian model mixing approach to symmetric nuclear matter
A. C. Semposki🇺🇸 · C. Drischler🇺🇸 · R. J. Furnstahl🇺🇸 · J. A. Melendez🇺🇸 · D. R. Phillips🇺🇸
Constraining the equation of state (EOS) of strongly interacting, dense matter is the focus of intense experimental, observational, and theoretical effort. Chiral effective field theory ( $χ$ EFT) can describe the EOS between the typical densities of nuclei and those in the outer cores of neutron stars while perturbative QCD (pQCD) can be applied to properties of deconfined quark matter, both with quantified theoretical uncertainties. However, describing the full range of densities in between with a single EOS that has well-quantified uncertainties is a challenging problem. Bayesian multi-model inference from $χ$ EFT and pQCD can help bridge the gap between the two theories. In this work, we introduce a correlated Bayesian model mixing framework that uses a Gaussian Process (GP) to assimilate different information into a single QCD EOS for symmetric nuclear matter. The present implementation uses a stationary GP to infer this mixed EOS solely from the EOSs of $χ$ EFT and pQCD while accounting for the truncation errors of each theory. The GP is trained on the pressure as a function of number density in the low- and high-density regions where $χ$ EFT and pQCD are, respectively, valid. We impose priors on the GP kernel hyperparameters to suppress unphysical correlations between these regimes. This, together with the assumption of stationarity, results in smooth $χ$ EFT-to-pQCD curves for both the pressure and the speed of sound. We show that using uncorrelated mixing requires uncontrolled extrapolation of at least one of $χ$ EFT or pQCD into regions where the perturbative series breaks down and leads to an acausal EOS. We also discuss extensions of this framework to non-stationary and less differentiable GP kernels, its future application to neutron-star matter, and the incorporation of additional constraints from nuclear theory, experiment, and multi-messenger astronomy.
nucl-thastro-ph.HEhep-phPRC(2025)·30 citations
05
Thermal fluctuations of matter composition and quark nucleation in compact stars
Mirco Guerrini🇮🇹 · Giuseppe Pagliara🇮🇹 · Alessandro Drago🇮🇹 · Andrea Lavagno🇮🇹
At the extreme densities reached in the core of neutron stars, it is possible that quark deconfined matter is produced. The formation of this new phase of strongly interacting matter is likely to occur via a first-order phase transition for the typical temperatures reached in astrophysical processes. The first seeds of quark matter would then form through a process of nucleation within the metastable hadronic phase. Here we address the role of the thermal fluctuations in the hadronic composition on the nucleation of two-flavour quark matter. At finite temperature, thermodynamic quantities in a system fluctuate around average values. Being nucleation a local process, it is possible that it occurs in a subsystem whose composition makes the nucleation easier. We will consider the total probability of the nucleation as the product between the probability that a subsystem has a certain hadronic composition different from the average in the bulk, and the nucleation probability in that subsystem. We will show how those fluctuations of the hadronic composition can increase the efficiency of nucleation already for temperatures $\sim (0.1 - 1)$ keV. However, for temperatures $≲ (1 - 10)$ MeV, the needed overpressure exceeds the maximum pressure reached in compact stars. Finally, for even larger temperatures the process of nucleation can take place, even taking into account finite size effects.
nucl-thastro-ph.HEApJ(2024)·5 citations
06
Integral identities and universal relations for solitons
Christoph Adam🇪🇸 · Alberto Garcia Martin-Caro🇪🇸 · Carlos Naya🇪🇸 · Andrzej Wereszczynski🇵🇱
We show that any nonlinear field theory giving rise to static solutions with finite energy like, e.g., topological solitons, allows us to derive an infinite number of integral identities which any such solution has to obey. These integral identities can always be understood as being generated by field transformations and their related Noether currents. We also explain why all integral identities generated by coordinate transformations become trivial for Bogomolnyi-Prasad-Sommerfield (BPS) solitons, i.e., topological solitons which saturate a topological energy bound. Finally, we consider applications of these identities to a broad class of nonlinear scalar theories, including the Skyrme model. More concretely, we find nontrivial integral identities that can be seen as model-independent relations between certain physical properties of the solitons in such theories, and we comment on the possible connection between these new relations and those already found in the context of astrophysical compact objects. We also demonstrate the usefulness of said identities to estimate the precision of the numerical calculation of soliton observables.
↳ hep-thgr-qcmath-phmath.MP+1PRD(2024)·4 citations
07
Entanglement suppression and low-energy scattering of heavy mesons
Tao-Ran Hu🇨🇳 · Su Chen🇨🇳 · Feng-Kun Guo🇨🇳
Recently entanglement suppression was proposed to be one possible origin of emergent symmetries. Here we test this conjecture in the context of heavy meson scatterings. The low-energy interactions of $D^{(*)} D ˉ^{(*)}$ and $D^{(*)} D^{(*)}$ are closely related to the hadronic molecular candidates $X (3872)$ and $T_{cc} (3875)^{+}$ , respectively, and can be described by a nonrelativistic effective Lagrangian manifesting heavy-quark spin symmetry, which includes only constant contact potentials at leading order. We explore entanglement suppression in a tensor-product framework to treat both the isospin and spin degrees of freedom. Using the $X (3872)$ and $T_{cc} (3875)^{+}$ as inputs, we find that entanglement suppression indeed leads to an emergent symmetry, namely, a light-quark spin symmetry, and as such the $D^{(*)} D ˉ^{(*)}$ or $D^{(*)} D^{(*)}$ interaction strengths for a given total isospin do not depend on the total angular momentum of light (anti)quarks. The $X (3872)$ and $T_{cc} (3875)^{+}$ are predicted to have five and one isoscalar partner, respectively, while the corresponding partner numbers derived solely from heavy-quark spin symmetry are three and one, respectively. The predictions need to be confronted with experimental data and lattice quantum chromodynamics results to further test the entanglement suppression conjecture.
↳ hep-phhep-exhep-thnucl-th+1PRD(2024)·23 citations
08
Nuclear charge radii of germanium isotopes around $N$ = 40
S. J. Wang🇨🇳 · A. Kanellakopoulos🇧🇪 · X.F. Yang🇨🇳 · S. W. Bai🇨🇳 · J. Billowes🇬🇧 · M. L. Bissell🇬🇧 · K. Blaum🇩🇪 · B. Cheal🇬🇧 · C. S. Devlin🇬🇧 · R. F. Garcia Ruiz🇺🇸 · J. Z. Han🇨🇳 · H. Heylen🇨🇭 and 17 other authors
Collinear laser spectroscopy measurements were performed on $^{68 - 74}$ Ge isotopes ( $Z = 32$ ) at ISOLDE-CERN, by probing the $4 s^{2} 4 p^{2}^{3} P_{1} \to 4 s^{2} 4 p 5 s^{3} P_{1}^{o}$ atomic transition (269~nm) of germanium. Nuclear charge radii are determined via the measured isotope shifts, revealing a larger local variation than the neighboring isotopic chains. Nuclear density functional theory with the Fayans functionals Fy( $Δ r$ ,HFB) and Fy(IVP), and the SV-min Skyrme describes the experimental data for the differential charge radii $δ ⟨ r^{2} ⟩$ and charge radii $R_{c}$ within the theoretical uncertainties. The observed large variation in the charge radii of germanium isotopes is better accounted for by theoretical models incorporating ground state quadrupole correlations. This suggests that the polarization effects due to pairing and deformation contribute to the observed large odd-even staggering in the charge radii of the Ge isotopic chain.
↳ nucl-exnucl-thPLB(2024)·15 citations
09
Study of the timelike electromagnetic form factors of the $Λ_{c}$
Di Guo🇨🇳 · Qin-He Yang🇨🇳 · Ling-Yun Dai🇨🇳
In this paper, the reaction of electron-positron annihilation into $Λ_{c}^{+} Λ ˉ_{c}^{-}$ is investigated. The $Λ_{c}^{+} Λ ˉ_{c}^{-}$ scattering amplitudes are obtained by solving the Lippmann-Schwinger equation. The contact, annihilation, and two pseudoscalar-exchange potentials are taken into account in the spirit of the chiral effective field theory. The amplitudes of $e^{+} e^{-} \to Λ_{c}^{+} Λ ˉ_{c}^{-}$ are constructed by the distorted wave Born approximation method, with the final state interactions of the $Λ_{c}^{+} Λ ˉ_{c}^{-}$ re-scattering implemented. By fitting to the experimental data, the unknown couplings are fixed, and high-quality solutions are obtained. With these amplitudes, the individual electromagnetic form factors in the timelike region, $G_{E}^{Λ_{c}}$ , $G_{M}^{Λ_{c}}$ , and their ratio, $G_{E}^{Λ_{c}} / G_{M}^{Λ_{c}}$ , are extracted. Both modulus and phases are predicted. These individual electromagnetic form factors reveal new insights into the properties of the $Λ_{c}$ . The separated contributions of the Born term, contact, annihilation, as well as the two pseudoscalar exchange potentials to the electromagnetic form factors are isolated. It is found that the Born term dominates the whole energy region. The contact term plays a crucial role in the enhancement near the threshold, and the annihilation term is essential in generating the fluctuation of the electromagnetic form factors.
↳ hep-phnucl-thPRD(2024)·6 citations
10
Stress out of charmonia
Siqi Xu🇨🇳 · Xianghui Cao🇨🇳 · Tianyang Hu🇨🇳 · Yang Li🇨🇳 · Xingbo Zhao🇨🇳 · James P. Vary🇺🇸
We investigate the gravitational form factors of charmonium. Our method is based on a Hamiltonian formalism on the light front known as basis light-front quantization. The charmonium mass spectrum and light-front wave functions were obtained from diagonalizing an effective Hamiltonian that incorporates confinement from holographic QCD and one-gluon exchange interaction from light-front QCD. We proposed a quantum many-body approach to construct the hadronic matrix elements of the energy momentum tensor $T^{++}$ and $T^{+-}$ , which are used to extract the gravitational form factors $A (Q^{2})$ and $D (Q^{2})$ . The obtained form factors satisfy the known constraints, e.g. von Laue condition. From these quantities, we also extract the energy, pressure and light-front energy distributions of the system. We find that hadrons are multi-layer systems.
↳ hep-phnucl-thPRD(2024)·12 citations
11
Quantum Simulating Nature's Fundamental Fields
Christian W. Bauer🇺🇸 · Zohreh Davoudi🇺🇸 · Natalie Klco🇺🇸 · Martin J. Savage🇺🇸
Simulating key static and dynamic properties of matter -- from creation in the Big Bang to evolution into sub-atomic and astrophysical environments -- arising from the underlying fundamental quantum fields of the Standard Model and their effective descriptions, lies beyond the capabilities of classical computation alone. Advances in quantum technologies have improved control over quantum entanglement and coherence to the point where robust simulations are anticipated to be possible in the foreseeable future. We discuss the emerging area of quantum simulations of Standard-Model physics, challenges that lie ahead, and opportunities for progress in the context of nuclear and high-energy physics.
↳ hep-phnucl-thquant-phNature Rev.Phys.(2023)·226 citations
12
Three ways to decipher the nature of exotic hadrons: multiplets, three-body hadronic molecules, and correlation functions
Ming-Zhu Liu🇨🇳 · Ya-Wen Pan🇨🇳 · Zhi-Wei Liu🇨🇳 · Tian-Wei Wu🇨🇳 · Jun-Xu Lu🇨🇳 · Li-Sheng Geng🇨🇳
In the past two decades, a plethora of hadronic states beyond the conventional quark model of $q q ˉ$ mesons and $q q q$ baryons have been observed experimentally, which motivated extensive studies to understand their nature and the non-perturbative strong interaction. Since most of these exotic states are near the mass thresholds of a pair of conventional hadrons, the prevailing picture is that they are primarily hadronic molecules. In principle, one can verify the molecular nature of these states by thoroughly comparing their masses, decay widths, and production rates in a particular picture with experimental data. However, this is difficult or impossible. First, quantum mechanics allows for the mixing of configurations allowed by symmetries and quantum numbers. Second, data are relatively scarce because of their small production rates and the many difficulties in the experimental measurements. As a result, other alternatives need to be explored. This review summarizes three such approaches that can help disentangle the nature of the many exotic hadrons discovered. In the first approach, based on the molecular interpretations for some exotic states, we study the likely existence of multiplets of hadronic molecules related by various symmetries, such as isospin symmetry, SU(3)-flavor symmetry, heavy quark spin/flavor symmetry, and heavy antiquark diquark symmetry. In the second approach, starting from some hadronic molecular candidates, one can derive the underlying hadron-hadron interactions. With these interactions, one can study related three-body systems and check whether three-body bound states/resonances exist. In the third approach, one can turn to the femtoscopy technique to derive the hadron-hadron interactions, hence inaccessible. This technique provided an unprecedented opportunity to understand the interactions between unstable hadrons.
↳ hep-phhep-exhep-latnucl-ex+1Phys.Rept.(2025)·218 citations
13
Lattice determination of the Batalin-Vilkovisky function and the strong running interaction
A. C. Aguilar🇧🇷 · N. Brito🇵🇹 · M. N. Ferreira🇪🇸 · J. Papavassiliou🇪🇸 · O. Oliveira🇵🇹 · P. J. Silva🇵🇹
The Batalin-Vilkovisky function is a central component in the modern formulation of the background field method and the physical applications derived from it. In the present work we report on novel lattice results for this particular quantity, obtained by capitalizing on its equality with the Kugo-Ojima function in the Landau gauge. The results of the lattice simulation are in very good agreement with the predictions derived from a continuum analysis based on the corresponding Schwinger-Dyson equations. In addition, we show that an important relation connecting this function with the ghost propagator is fulfilled rather accurately. With the aid of these results, we carry out the first completely lattice-based determination of the process-independent strong running interaction, employed in a variety of phenomenological studies.
↳ hep-lathep-phhep-thnucl-thPLB(2024)·5 citations

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