Nuclear Theory·nucl-th

Friday·August 8, 2025

17 papers—13 primary·4 cross-listed

01
Ab Initio Study of $^{7}$ Li with Coupled Mass Partitions
Jakub Herko (1, 2 and 3)🇨🇦 · Konstantinos Kravvaris (3)🇺🇸 · Petr Navrátil (1 and 4)🇨🇦 · Sofia Quaglioni (3)🇺🇸 · Guillaume Hupin (5)🇫🇷 · Mark A. Caprio (2) ((1) TRIUMF, (2) Department of Physics and Astronomy, University of Notre Dame, (3) Lawrence Livermore National Laboratory, (4) University of Victoria, (5) Université Paris-Saclay, CNRS/IN2P3, IJCLab)🇺🇸
Background: Lithium is of broad interest in nuclear astrophysics, fusion energy research, and nuclear technology. From a theoretical perspective, the nucleus $^{7}$ Li presents a remarkable challenge, as its bound and resonant states can exhibit contributions from both the $^{4}$ He + $^{3}$ H cluster configuration and configurations involving a neutron or proton coupled to a $^{6}$ Li or $^{6}$ He core, respectively. Purpose: We aim to achieve a unified ab initio description of bound-state and continuum properties of $^{7}$ Li by explicitly including simultaneously the coupled mass/charge partitions $^{4}$ He + $^{3}$ H, $^{6}$ Li + $n$ , and $^{6}$ He + $p$ . Specifically, we investigate the effect of inter-partition coupling on the spectrum of $^{7}$ Li and calculate cross sections for the $^{6}$ Li( $n, p)^{6}$ He, $^{6}$ He( $p, n)^{6}$ Li, and $^{6}$ He( $p, t)^{4}$ He reactions. Method: We employ the no-core shell model with continuum for the first time in a calculation that couples three mass/charge partitions of the aggregate nucleus $^{7}$ Li, using a chiral nucleon-nucleon interaction as input. Results: The calculated spectrum reproduces all the experimentally observed states of $^{7}$ Li in the correct order and predicts additional resonances. The calculation also reproduces the overall energy dependence of the $^{6}$ Li $(n, p)^{6}$ He cross section. Improved agreement with measured cross sections is obtained after phenomenological adjustment of resonance energies. Conclusions: The present results show that coupling the relevant mass/charge partitions is important for a consistent description of the $^{7}$ Li spectrum and reaction cross sections, and offers a useful framework for interpreting existing data and guiding future measurements.
nucl-thnucl-exPRC(2026)·1 citation
02
Acausality-driven instabilities in transient relativistic viscous hydrodynamics
Lorenzo Gavassino · Henry Hirvonen · Jean-François Paquet · Mayank Singh · Gabriel Soares Rocha
We investigate non-linear instabilities stemming from superluminal propagation of information in Israel-Stewart-like models of relativistic viscous fluid dynamics. In relativity, the characteristic speed of propagation of information, $w$ , and the speed of the fluid, $v$ , allow us to differentiate between regimes of the hydrodynamic equations that are acausal but stable ( $w > 1$ ), unstable ( $v^{2} w^{2} \geq 1$ ), and covariantly ill-posed ( $w^{2} \leq 0$ ). As an analytical benchmark, we present a new solution that illustrates these distinct regimes. We compare this analytical solution to the result of a numerical relativistic viscous fluid dynamics solver, and confirm that the analytical result can be recovered numerically in the stable regime, whether causal or acausal. The onset of numerical instabilities is further found to occur in the regime predicted by the analytical solution.
nucl-thhep-phPRD(2025)·5 citations
03
Long-Range $N - J / ψ$ Interaction from an Operator Product Expansion Perspective
Seokwoo Yeo🇰🇷 · In Woo Park🇰🇷 · Su Houng Lee🇰🇷
A recent lattice QCD study has shown that the $N - J / ψ$ potential is attractive at all distances, and its long-range tail is well described by two-pion exchange. Here, we study to what extent the long-range part of the attraction can be reproduced from the perspective of the operator product expansion (OPE). This is accomplished by extracting the leading-order four-quark operator that couples to two pions and calculating its contribution to the $J / ψ$ mass in nuclear matter, to linear order in density, within the QCD sum rule framework. Using previous estimates of the four-quark operators for the chiral symmetric and breaking parts, we obtain a mass decrease that is smaller in magnitude but qualitatively consistent with the attraction obtained in the lattice QCD calculation. By expressing the interaction in terms of four-quark operators, we can analyze the effects of chiral symmetry restoration in dense matter on the masses of the $J / ψ$ and other mesons composed of heavy quarks.
nucl-thhep-phPRD(2025)·2 citations
04
Analysis of (p, $γ$ ) capture cross-sections relevant to p-process using TALYS for A=75-110
Satabdi Mondal · Enakshi Senapati · Deepak Pandit · Balaram Dey · Pampa Das · Alokkumar De · Srijit Bhattacharya
The proton capture (p, $γ$ ) cross-sections for eight different atomic nuclei in the mass region A=75-110 were calculated within the nuclear reaction model code TALYS. For all the reactions, we tested different combinations of inputs for level density (l.d) parameter and gamma strength function ( $γ_{s f}$ ). Finally, it was observed that application of hybrid input in TALYS (macroscopic l.d and microscopic or semi-microscopic $γ_{s f}$ or in abbreviation mac-mic) resulted successful agreement of theoretical prediction with the existing experimental data. Isospin correction was also incorporated in a few cases which improved the matching if the centre of mass energy reaches the threshold energy of the opening of (p,n) channel. The corresponding thermonuclear reaction rates were calculated for all the nuclei and some discrepancies were found with the prediction of the NON-SMOKER code. Using the particular mac-mic input combination, the cross-section and reaction rate for the nuclei $^{92}$ Nb and $^{92}$ Mo are calculated within TALYS. These two nuclei lack experimental data but are highly important for understanding early solar system processes. This is a rare attempt to explain the p-capture cross-section of different p-nuclei (A=75-110 range) with similar set of input combinations in TALYS, which may help to remove the uncertainty generated due to the variation of input parameters within nuclear statistical model code
nucl-thnucl-exIJMPE(2026)·0 citations
05
Probing surface vibration of spherical nuclei in relativistic heavy-ion collisions
Kouichi Hagino🇯🇵 · Masakiyo Kitazawa🇯🇵
There has been increasing interest in recent years in using relativistic heavy-ion collisions to probe nuclear structure, such as static nuclear deformation. Here we discuss the role of quantum zero-point fluctuations of the surface vibration of spherical nuclei in relativistic heavy-ion collisions. To this end, we employ an approach to describe the vibration in the space-fixed frame, which has been well established in the field of low-energy heavy-ion fusion reactions. We particularly consider the quadrupole vibration of $^{58}$ Ni in $^{58}$ Ni+ $^{58}$ Ni reaction and the octupole vibration of $^{208}$ Pb in $^{208}$ Pb+ $^{208}$ Pb reaction. We show that the surface vibration leads to comparable eccentricity parameters to those for static deformation, while they give significantly different distributions of the initial states, suggesting the importance of the proper treatment of the surface vibration in heavy-ion collisions. We perform similar analysis also for triaxial deformation and gamma-soft vibration.
nucl-thhep-phnucl-exPRC(2025)·10 citations
06
Ab initio description of hypernuclei
Johann Haidenbauer🇩🇪 · Ulf-G. Meißner🇩🇪 · Andreas Nogga🇩🇪
Hypernuclei are bound states of neutrons, protons and one or two hyperons, thus extending the nuclear landscape to a third dimension. They also encode information about the baryon-baryon and three-baryon interactions. Here, we review recent work on chiral effective field theory for two- and three-baryon interactions and their application in nuclei based on ab initio methods. These include the Faddeev-Yakubovsky equations, the no-core-shell-model (NCSM) and nuclear lattice effective field theory (NLEFT). Besides of providing an overview of the formalisms explicit results for the separation energies of light $Λ$ hypernuclei are provided. Two-body and three-body forces are included consistently, in line with the underlying power counting. Calculations of $Λ$ hypernuclei within the NCSM, performed up to A=7 so far, suggest that agreement with the experimental binding energies can be achieved once appropriate three-body forces are taken into account. Similar conclusions are drawn from the study based on NLEFT, where even hypernuclei up to A=16 can be computed. Additionally, applications of ab initio approaches in calculations of $ΛΛ$ and $Ξ$ hypernuclei are discussed and possible candidates for the lightest systems that could be bound are identified, namely $_{ΛΛ}^{5} He$ and $_{Ξ}^{4} H$ .
nucl-thPPNP(2026)·14 citations
07
Quadrupole-hexadecapole coupling in the rare earth region with beyond mean field correlations
R. Rodriguez-Guzman · L.M. Robledo
The roles of static hexadecapole deformation and beyond-mean-field quadrupole-hexadecapole configuration mixing are studied for a selected set of Yb, Hf, W and Os isotopes within the mass range $170 \leq A \leq 202$ , using the Hartree-Fock-Bogoliubov (HFB) and the two-dimensional Generator Coordinate Method (2D-GCM) approaches, based on the Gogny energy density functional. The 2D-GCM ground and excited states of the lighter isotopes are associated with diamond-like shapes while, for each isotopic chain, a region where those states correspond to square-like shapes has been found below the neutron shell closure $N = 126$ . It is shown, that for the studied nuclei the quadrupole and hexadecapole degrees of freedom are interwoven in the ground and excited states up to the mass number $A = 184 - 188$ . This structural evolution, encoded in the 2D-GCM collective wave functions, is accompanied by an enhanced prolate-oblate shape coexistence around the neutron number $N = 116$ . In agreement with previous studies, it is also shown that for the considered Yb, Hf, W and Os isotopes the inclusion of hexadecapole deformation in the ground state dynamics leads to a non trivial additional correlation energy comparable to the quadrupole correlation energy itself.
nucl-thEPJA(2025)·2 citations
08
Anomalous Behavior of Giant Monopole Resonance Energy with Nuclear Matter Incompressibility in the framework of Relativistic Mean Field Formalism and Coherent Density Fluctuation Model
Jeet Amrit Pattnaik · R. N. Panda · M. Bhuyan · S. K. Patra
The finite nucleus incompressibility $K^{A}$ is evaluated using the coherent density fluctuation model with the extended relativistic mean field density. The relativistic energy density functional for nuclear matter is replaced by the local density approximation for finite nuclei. The equation is used to calculate the finite nuclear incompressibility, which is further utilized to evaluate the isoscalar giant monopole excitation (ISGMR) energy $E_{M}$ . This excitation energy is compared with other theoretical calculations and experimental data, wherever available. The results are comparable to the data. In contrast to the general understanding, the $E_{M}$ of finite nucleus is found to be maximum for the lowest nuclear matter incompressibility $K_{\infty}$ , whereas it is minimum for the maximum $K_{\infty}$ . These reverse results may be due to the self- and cross-interactions of the vector mesons in the nuclear potential.
nucl-th1 citation
09
A Resummed Hydrodynamic Description of Relativistic Heavy-ion Collisions
Cheng Chiu🇺🇸 · Gabriel Denicol🇧🇷 · Matthew Luzum🇧🇷 · Chun Shen🇺🇸
We introduce a resummed hydrodynamic scheme for evolving the viscous stress tensors in relativistic viscous hydrodynamics, based on which the necessary non-linear causality conditions can be imposed. When the magnitudes of the shear and bulk viscous stress tensors are small relative to the ideal part energy-momentum tensor, this new resummed scheme reduces to the standard second-order relativistic hydrodynamic theories. Nontrivial nonlinear corrections from high-order gradient terms retain the sizes of shear and bulk viscous stress tensors within tunable maximum allowed values. We perform event-by-event simulations for Pb+Pb and p+Pb collisions at 5.02 TeV to quantify the theoretical uncertainties from this resummed scheme on final-state flow observables.
nucl-thhep-ph2 citations
10
Mode-by-mode evolution of Pb-Pb collisions at 5.02 TeV in a hybrid model
Renata Krupczak🇩🇪 · Nicolas Borghini🇩🇪 · Hendrik Roch🇺🇸
We determine the average state and the uncorrelated modes that characterize the event-by-event fluctuations of the initial state in two typical centrality classes of Pb-Pb collisions at 5.02 TeV. We find that modes in a narrow central bin are similar to those in events at fixed vanishing impact parameter, while those in a mid-peripheral centrality class are affected by the impact-parameter variation. We study how each fluctuation mode affects observables both in the initial state and in the final state of the collisions, at the end of a state-of-the-art boost-invariant hybrid evolution with KoMPoST + MUSIC + iSS + SMASH, and show that implementing a hadronic transport cascade in such a mode-by-mode analysis with reasonable statistical noise is costly but feasible.
nucl-thhep-phEPJC(2025)·1 citation
11
Features of Two-Quasiparticle Rotational Bands in Deformed Odd-Odd Nuclei, $156 \leq A \leq 168$
Pinky · Sushil Kumar · Sukhjeet Singh · A.K. Jain
In present work, we evaluated the experimental data pertains to two quasiparticle rotational structures in deformed odd-odd nuclei in rare earth mass region. The compilation includes total 234 rotational bands among which 173 are rotational bands and 61 bandhead states. Gallagher Moszkowski doublets are identified for 63 two quasiparticle configurations which provide a good testing ground for np residual interaction systematics. The highest excitation energies reach approximately 18 MeV in 164Lu and 168Lu nuclide. The triplet configuration becomes ground state in case of 22 nuclides namely 156-170Ho, 156-176Tm and 162-168Lu. Signature splitting is reported for 76 bands and signature inversion is identified in 29 bands which indicate the presence of Coriolis couplings and evolving configuration mixing with spin. The average signature splitting amplitudes lies between 12 to 300 keV. Band crossings have been observed in case of 10 bands, often accompanying changes in the kinematic and dynamic moments of inertia as paired high-j quasiparticles align with the rotational axis. Halflife information is available for 58 bandhead. The branching ratios and effective gfactors remain scares. In total, 137 bands display regular level sequences of energy levels whereas 8 exhibit irregular patterns. The present evaluation of two quasiparticle rotational bands reveals substantial gaps in the experimental data and highlight the need of fresh measurements to support rigorous calculations and reliable systematics.
nucl-th0 citations
12
Weak interaction rates of $s d$ -shell Urca pairs in stellar environment using a shell-model approach
Shweta Sharma🇮🇳 · Praveen C. Srivastava🇮🇳 · Toshio Suzuki🇯🇵
In this work, the weak interaction rates of $s d$ -shell nuclei in the hot and dense stellar environment are calculated using the shell model. The {\it ab initio} effective interactions are employed for the calculation of Gamow-Teller strengths and weak rates in addition to the phenomenological interaction. The weak rates are evaluated in a fine grid of density and temperature. The electron capture and $β^{-}$ -decay rates of Urca pairs of nuclei with $A = 23, 25, 29, 31$ and 33 are evaluated as a function of $lo g_{10} ρ Y_{e}$ and the corresponding Urca density is obtained. The screening effects are also included for the evaluation of these stellar weak rates. In addition, the intrinsic cooling strength is evaluated for $A = 29, 31$ and 33 Urca pairs in neutron star crusts. The stellar weak rates, along with the neutrino energy emitted and the gamma heat production, are tabulated for $A = 29 - 39$ nuclei.
nucl-thnucl-exPRC(2025)·3 citations
13
Modelling and Systematics of $\frac{1}{2} [521] ν$ Quasiparticle Rotational Bands in $N = 99, 101, 103$ Isotonic Chains
Pinky · Sushil Kumar · Sukhjeet Singh · A.K. Jain
We analyze the $\frac{1}{2} [521] ν$ quasiparticle rotational bands along the $N = 99, 101, 103$ isotonic chains using semi-empirical model in which first and higher order Coriolis terms are treated perturbatively. A dedicated Python routine optimizes five parameters bandhead energy, inertia A, decoupling a, and Coriolis coefficients B and C for each nucleus. The calculations match experimental level spacings to within 5 keV. Staggering keeps a common phase across the three chains yet grows with spin and, on average, with both neutron and proton number. The inertia parameter rises smoothly with Z (e.g., A for N = 99: 10.6 to 12.4 keV), signaling a decrease in the moment of inertia as axial deformation weakens. Decoupling parameter a increases and then saturates for N = 99 and 103, indicating purer K = 1/2 structure at high Z; the N = 101 chain shows the opposite trend, pointing to stronger configuration mixing. The first order Coriolis term B becomes increasingly negative with Z, whereas the higher order term C shows chain specific sign changes. The present work, explore the dynamics of various physical parameters associated with {\nu}1/2[521] quasiparticle rotational bands and helps to understand observed signature effects.
nucl-th0 citations
14
Anisotropic modifications to the transport phenomena and observables in a hot QCD medium at finite baryon asymmetry
Shubhalaxmi Rath🇨🇱
We have studied how the transport of charge and heat as well as associated observables become influenced by a weak-momentum anisotropy arising due to the asymptotic expansion of baryon asymmetric matter in the initial stages of heavy ion collisions. This study facilitates the understanding of the local equilibrium property of the medium through the Knudsen number, and explores the correlation between the heat flow and the charge flow through the Lorenz number in the Wiedemann-Franz law for an anisotropic hot QCD medium at finite baryon asymmetry. We have determined the electrical and the thermal conductivities by solving the relativistic Boltzmann transport equation in the relaxation time approximation within the kinetic theory approach. The interactions among partons are appended through their distribution functions within the quasiparticle model of the hot QCD medium at finite temperature, anisotropy and baryon asymmetry. We have observed a decrease in both electrical and thermal conductivities in the presence of expansion-induced anisotropy for baryonless scenario as well as for baryon asymmetric scenario. Conversely, these conductivities are found to be larger in the baryon asymmetric matter as compared to their counterparts in the baryonless matter. The impact of anisotropy on the baryon asymmetric matter is as conspicuous as on the baryonless matter. The above results are attributed to the squeezing of the distribution function due to the momentum anisotropy generated by the asymptotic expansion of baryon asymmetric matter and the dispersion relations of partons in the presence of anisotropy. Additionally, the aforesaid observables are also modulated by the expansion-induced anisotropy in the baryon asymmetric medium, indicating new predictions for the equilibrium characteristic and the relative behavior between the heat and charge flow for the said medium.
↳ hep-phhep-thnucl-thEPJA(2026)·3 citations
15
Optimal Qubit Purification and Unitary Schur Sampling via Random SWAP Tests
Shrigyan Brahmachari🇺🇸 · Austin Hulse🇺🇸 · Henry D. Pfister🇺🇸 · Iman Marvian🇺🇸
The goal of qubit purification is to combine multiple noisy copies of an unknown pure quantum state to obtain one or more copies that are closer to the pure state. We show that a simple protocol based solely on random SWAP tests achieves the same fidelity as the Schur transform, which is optimal. This protocol relies only on elementary two-qubit SWAP tests, which project a pair of qubits onto the singlet or triplet subspaces, to identify and isolate singlet pairs, and then proceeds with the remaining qubits. For a system of $n$ qubits, we show that after approximately $T \approx n ln n$ random SWAP tests, a sharp transition occurs: the probability of detecting any new singlet decreases exponentially with $T$ . Similarly, the fidelity of each remaining qubit approaches the optimal value given by the Schur transform, up to an error that is exponentially small in $T$ . More broadly, this protocol achieves what is known as weak Schur sampling and unitary Schur sampling with error $ϵ$ , after only $2 n ln (n ϵ^{- 1})$ SWAP tests. That is, it provides a lossless method for extracting any information invariant under permutations of qubits, making it a powerful subroutine for tasks such as quantum state tomography and metrology.
↳ quant-phcond-mat.dis-nncond-mat.stat-mechmath-ph+25 citations
16
On the origin of the $N c^{1}$ scaling in the confined but chirally symmetric phase at high T
L. Ya. Glozman🇦🇹
There is lattice evidence that the QCD matter above the chiral restoration temperature Tch and below the deconfinement temperature Td, called stringy fluid, is characterized by an approximate chiral spin symmetry, which is a symmetry of confinement in QCD with light quarks. The energy density, pressure and entropy density in the stringy fluid scale as Nc^1, which is in contrast to the Nc^0 scaling in the hadron gas and to the Nc^2 scaling in the quark-gluon plasma. Here we clarify the origin of the Nc^1 scaling. We employ a solvable field-theoretical large $N_{c}$ chirally symmetric and confining model. In vacuum the confining potential induces a spontaneous breaking of chiral symmetry. The mesons are spatially localized states of quarks and antiquarks. Still in the confining regime the system undergoes the chiral restoration phase transition at $T_{c h}$ because of Paili blocking of the quark levels required for the existence of the quark condensate, by the thermal excitation of quarks and antiquarks. The same Paili blocking leads to a delocalization of the color singlet low-spin meson-like states that become infinitely large in the chiral limit. Consequently the stringy fluid represents a very dense medium of the overlapping huge color-singlet low-spin quark-antiquark systems. The Bethe-Salpeter equation that determines the rest-frame excitation energies of the color-singlet quark-antiquark system is Nc-independent both in vacuum and in the medium in the confining regime. The excitation energy of the quark-antiquark color-singlet systems scales as Nc^0, i.e. as meson mass in vacuum. The Nc^1 scaling of the energy density in the stringy fluid is provided by the fluctuations of the color-singlet quark-antiquark systems.
↳ hep-phhep-lathep-thnucl-thEPJC(2025)·4 citations
17
Vertex corrections and wavefunction renormalization for atoms, nuclei, and other heavy composite particles
Ryan Plestid🇺🇸 · Mark B. Wise🇺🇸
We study QED corrections to operator matrix elements involving heavy composite particles (e.g., heavy-mesons, nuclei, and atoms). We define a new notion of reducible and irreducible graphs which is useful for systems with many discrete excited states. The equivalence of the LSZ reduction formula and old fashioned perturbation theory is explicitly demonstrated. The self energy and vertex corrections are defined (to all orders), and the one-loop corrections are reduced to operator matrix elements which may be evaluated by hadronic, nuclear, or atomic theorists. The gauge dependence of the various pieces are studied in detail at one loop, and cancellation of spurious contributions are demonstrated in a class of covariant gauges; Coulomb gauge is also discussed. The formalism is applied to superallowed beta decay where the one-loop structure is connected to existing literature based on current algebra techniques. We further identify the well known $O (Z^{2} α^{2})$ isospin breaking correction from the intranuclear Coulomb field as arising from two-loop diagrams. We comment on future applications of our results to the radiative corrections necessary in extractions of $∣ V_{u d} ∣$ , in particular for corrections that required beyond one-loop order.
↳ hep-phhep-thnucl-thPRD(2026)·4 citations

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