Nuclear Theory·nucl-th

Monday·June 30, 2025

13 papers—5 primary·8 cross-listed

01
Four types of phase transitions in interacting boson (meson) matter at high temperatures
D. Anchishkin🇺🇦 · V. Gnatovskyy🇺🇦 · D. Zhuravel🇺🇦 · I. Mishustin🇩🇪 · H. Stoecker🇩🇪
The thermodynamics of the interacting system of relativistic particles and antiparticles in the presence of a Bose-Einstein condensate was investigated within the framework of the mean-field model. It is assumed that the total isospin (charge) density is conserved. We show that, depending on the strength of the interaction, a bosonic particle-antiparticle system exhibits four types of phase transitions to the condensate phase. Three types correspond to the second-order phase transition, while one is a first-order phase transition.
nucl-thhep-thquant-phJ.Subatomic Part.Cosmol.(2025)·1 citation
02
Kinetic theories: from curved space to flat space
Shu Lin🇨🇳
We generalize the equivalence between off-equilibrium state and gravitational perturbation of equilibrium state from dynamics of macroscopic quantities to that of microscopic particles. We also generalize the equivalence to incorporate off-equilibrium state with vorticity by torsional perturbation to equilibrium state. The equivalence is achieved by mapping kinetic theories of spinless and spinning particles in torsional curved space to flat space through suitable choice of inertial frame that eliminates geodesic forces on particles. The equivalence has been shown for hydrodynamic and elastic regimes. In the latter case, we predict spin polarization induced by time-variation of shear strain in elastic materials. We also provide an order-of-magnitude estimate for the polarization in Dirac semi-metal.
nucl-thcond-mat.mes-hallgr-qchep-phPRD(2026)·0 citations
03
Nucleon-Quark Diquark-exchange Interaction
Th.A. Rijken🇳🇱
In this note the nucleon-quark diquark-exchange interaction is derived using the Feynman-propagator for axial-vector diquark (D) exchange. The Feynman diquark propagator is derived and the result is a (-)-sign difference w.r.t. quark-antiquark exchange. This is due to the (-)-sign for a closed fermion loop, present in for example vector and axial-vector quark-antiquark exchange, but absent in the case of D-exchange. The calculations in these notes follow closely those for vacuum polarisation in the literature. Taking into account that the diquark D is a color $\left{\bar{3}_c\right\}$ -state giving a factor +2. The result is an effective axial-vector diquark propagator. Application to $QN \to N Q$ gives a repulsive potential, which has been used in mixed nuclear-quark matter calculation.
nucl-thhep-ph0 citations
04
Spin polarization from nucleon-nucleon scatterings in intermediate-energy heavy-ion collisions
Rong-Jun Liu🇨🇳 · Jun Xu🇨🇳 · Yu-Gang Ma🇨🇳
We propose a new mechanism of generating spin polarization in heavy-ion collisions dominated by nucleon degree of freedom. By incorporating the spin change in nucleon-nucleon scatterings based on the phase shift data together with the constraint of rigorous angular momentum conservation and Pauli blocking, we illustrate through a Boltzmann-Uehling-Uhlenbeck transport model that appreciable spin polarization (about $1 \sim 2%$ ) can be generated in intermediate-energy heavy-ion collisions. This mechanism, together with the nuclear spin-orbit potential, may help to understand the spin polarization in few-GeV heavy-ion collisions dominated by nucleon degree of freedom.
nucl-thhep-exnucl-exPLB(2025)·4 citations
05
Exploring hadronic rescattering effects on resonance productions in pp and p-Pb collisions with PYTHIA8
Su-Jeong Ji🇰🇷 · Gyeongbin Park🇰🇷 · Bong-Hwi Lim🇯🇵 · Sanghoon Lim🇰🇷
In relativistic heavy-ion collisions, the quark-gluon plasma is created, and as the medium cools down, the system transitions into a hadronic phase. While such interactions are well established for large systems, such as Pb-Pb collisions, their relevance in smaller collision systems remains unclear. Consequently, hadronic interactions during the hadronic phase are studied in pp collisions at $s = 13$ TeV and p-Pb collisions at $s_{NN} = 5.02$ TeV with the PYTHIA8 event generator. The interaction is studied via the yield ratios between resonances and stable particles with similar quark contents, which are obtained as a function of transverse momentum ( $p_{T}$ ) using $ρ (770)^{0}$ , $K^{*} (892)^{0}$ , and $ϕ (1020)$ mesons and their stable particles, $π^{\pm}$ and $K^{\pm}$ at midrapidity ( $∣ y ∣ < 0.5$ ). Yield ratios are calculated in five multiplicity classes for pp and six for p-Pb collisions, using the 60-100% multiplicity class in pp as a reference. Although rescattering leads to stronger suppression at low $p_{T} < 2$ GeV/ $c$ , a visible suppression remains even when rescattering is turned off. To isolate the rescattering effect, double ratios between the rescattering on and off configurations are obtained. These are then integrated in the full $p_{T}$ range ( $0 < p_{T} < 6.0$ GeV/ $c$ ). The normalized double ratios show a decreasing trend with increasing multiplicity, independent of the collision system. The lower limit of the hadronic phase lifetimes extracted in the integrated- $p_{T}$ region increases with multiplicity in both systems, but with a notable discrepancy between pp and p-Pb collisions.
nucl-thnucl-exNPA(2026)·1 citation
06
Impact of magnetic field-driven anisotropies on the equation of state probed in neutron star mergers
Elias R. Most🇺🇸 · Jeffrey Peterson🇺🇸 · Luigi Scurto🇵🇹 · Helena Pais🇵🇹 · Veronica Dexheimer🇺🇸
Binary neutron star mergers can produce extreme magnetic fields, some of which can lead to strong magnetar-like remnants. While strong magnetic fields have been shown to affect the dynamics of outflows and angular momentum transport in the remnant, they can also crucially alter the properties of nuclear matter probed in the merger. In this work, we provide a first assessment of the latter, determining the strength of the pressure anisotropy caused by Landau level quantization and the anomalous magnetic moment. To this end, we perform the first numerical relativity simulation with a magnetic polarization tensor and a magnetic-field-dependent equation of state using a new algorithm we present here, which also incorporates a mean-field dynamo model to control the magnetic field strength present in the merger remnant. Our results show that -- in the most optimistic case -- corrections to the anisotropy can be in excess of $10%$ , and are potentially largest in the outer layers of the remnant. This work paves the way for a systematic investigation of these effects.
↳ astro-ph.HEgr-qcnucl-thApJL(2025)·13 citations
07
Universal Effective Charges in the $s d$ and $f p$ Shells
T. H. Ogunbeku🇺🇸 · J. M. Allmond🇺🇸 · T. J. Gray🇺🇸 · W.-J. Ong🇺🇸 · B. A. Brown🇺🇸 · A. Gargano🇮🇹 · R. Grzywacz🇺🇸 · J. D. Holt🇨🇦 · A. O. Macchiavelli🇺🇸 · T. Miyagi🇩🇪 · S. Neupane🇺🇸 · B. C. Rasco🇺🇸 and 70 other authors
The 247-keV state in $^{54}$ Sc, populated in the $β$ decay of $^{54}$ Ca, is reported here as a nanosecond isomer with a half-life of 26.0(22) ns. The state is interpreted as the $1^{+}$ member of the $π f_{7/2} \otimes ν f_{5/2}$ spin-coupled multiplet, which decays to the $3^{+}, π f_{7/2} \otimes ν p_{1/2}$ ground state. The new half-life corresponds to a pure $E 2$ transition with a strength of 1.93(16) W.u., providing the most precise, unambiguous $B (E 2)$ value in the neutron-rich $f p$ region to date for a nucleus with valence protons above $Z = 20$ . Notably, it is roughly four times larger than the $B (E 2; 1/ 2^{-} \to 5/ 2^{-})$ value in $^{55}$ Ca. The results, as compared to semi-empirical and ab initio shell-model calculations, indicate (1) a weak $N = 34$ sub-shell gap relative to $N = 32$ , (2) a large $E 2$ enhancement in Sc as compared to Ca due to $1 p - 1 h$ proton excitations across $Z = 28$ , and (3) empirical effective proton and neutron charges, $e_{π}$ = 1.30(8) $e$ and $e_{ν}$ = 0.452(7) $e$ , respectively, that are in contrast to reports of $e_{π} \approx 1.1 - 1.15 e$ and $e_{ν} \approx 0.6 - 0.8 e$ for $f p$ -shell nuclei near $N = Z$ . We demonstrate that these reports are erroneous and that, in fact, a universal set of effective charges can be used across the $s d$ and $f p$ shells.
↳ nucl-exnucl-thPRL(2025)·7 citations
08
Nature of the $P_{c}$ states from compositeness criteria
Yu-Fei Wang🇨🇳 · Chao-Wei Shen🇨🇳 · Deborah Rönchen🇩🇪 · Ulf-G. Meißner🇩🇪 · Bing-Song Zou🇨🇳 · Fei Huang🇨🇳
Based on a coupled-channel approach, we investigate the structures of four $P_{c}$ states through compositeness criteria. Toward a more precise description of the states, we have obtained refined fit results of the LHCb data on the $J / ψ p$ invariant mass distribution of the $Λ_{b}^{0} \to J / ψ p K^{-}$ decay. Allowing for the fact that each of the four $P_{c}$ states couples strongly to a nearby $S$ -wave channel, three criteria on the compositeness/elementariness are adopted in this study: the pole-counting rule, the spectral density function, and the Gamow wave function. Compositeness information is extracted from the scattering amplitudes and the pole parameters (pole positions and residues), without any preconceived assumptions on the nature of the $P_{c}$ states, and without any dependence on the model parametrization. Consistently within the framework of all the three methods, it has been found that the $P_{c} (4312) 1/ 2^{-}$ is mainly composed by $D ˉ Σ_{c}$ , $P_{c} (4380) 3/ 2^{-}$ by $D ˉ Σ_{c}^{*}$ , while the $P_{c} (4440) 1/ 2^{-}$ and $P_{c} (4457) 3/ 2^{-}$ states both turn out as composite states of $D ˉ^{*} Σ_{c}$ . The upper limits of the values of their elementariness are estimated to be rather small. This paper provides an additional confirmation of the molecular interpretation for the $P_{c}$ states in the literature.
↳ hep-phhep-thnucl-thPRD(2025)·4 citations
09
Eigenstates in coupled-channel scattering amplitude and their effects on spectrum
Takuma Nishibuchi🇯🇵 · Tetsuo Hyodo🇯🇵
In general, discrete eigenstates such as resonances are represented by poles of the scattering amplitude, analytically continued to the complex energy plane. In multi-channel scattering, however, the Riemann surface becomes more complicated, leading to the emergence of various types of poles with distinct characteristics. In this study, we investigate the relationship between poles located on different Riemann sheets and analyze how they influence the observable spectra. In particular, we clarify the effect of the decay channel on the pole trajectory, where an $s$ -wave bound state evolves into a resonance via a virtual state. It is shown that the quasibound state pole below the threshold does not continuously connected to the resonance pole above the threshold, and a kind of interchange of poles occurs. As a concrete example, we consider several models based on the chiral unitary approach that describe meson-baryon scattering amplitudes involving the $Ξ (1620)$ and $Ξ (1690)$ resonances. We examine their impact on the $π Ξ$ invariant mass distributions in the $Ξ_{c} \to π π Ξ$ decay, discussing how the pole structure manifests itself in experimental observables.
↳ hep-phnucl-thJ.Subatomic Part.Cosmol.(2026)·4 citations
10
Magneto-Thomson and transverse Thomson effects in an interacting hadron gas in the presence of an external magnetic field
Kamaljeet Singh🇮🇳 · Kshitish Kumar Pradhan🇮🇳 · Raghunath Sahoo🇮🇳
The universality of electric charge as a quantum number allows thermoelectric properties to manifest across diverse systems, starting from a hot quantum chromodynamic matter in heavy-ion collisions at a high energy scale to semiconductors in condensed matter systems at a low energy scale. In this work, we explore the emergence of magneto-transport phenomena, specifically the magneto-Thomson and transverse Thomson effects, in a hot and dense hadronic medium produced in relativistic heavy-ion collisions at the Relativistic Heavy Ion Collider and Large Hadron Collider energies. These phenomena arise due to the combined influence of temperature gradients and non-zero baryon chemical potential, particularly in the presence of an external magnetic field. Using the relativistic Boltzmann transport equation within the relaxation time approximation, we analyze the behavior of the hadronic medium considering different frameworks of hadron resonance gas models. The presence of external magnetic fields breaks the isotropy of the thermoelectric transport coefficient matrix, giving rise to new components of the Thomson coefficient, namely, magneto-Thomson and transverse Thomson coefficients. For the first time, we estimate the magneto-Thomson and transverse Thomson coefficients, which originate from the temperature dependence of the magneto-Seebeck coefficient and Nernst coefficient, respectively, in hadron gas under the influence of a static and time-varying magnetic field. Our findings provide a novel perspective on the higher-order thermoelectric properties of the hot and dense hadronic medium in the context of heavy-ion collisions.
↳ hep-phhep-exhep-thnucl-ex+1PRD(2026)·1 citation
11
Space-like pion off-shell form factors in the Bethe-Salpeter approach
S. Bondarenko (1,2)🇷🇺 · M. Slautin (1,2) ((1) Joint Institute for Nuclear Research, Dubna, Russia, (2) Dubna State University, Dubna, Russia)🇷🇺
In the paper, the off-shell electromagnetic pion form factors in the Bethe-Salpeter formalism are considered. The separable kernel of the first rank quark-antiquark interaction is used to solve the equation analytically. The semi-off-shell pion form factors $ F_1 $ and $ F_2 $, which are related to each other by the Ward-Takahashi identity, are calculated. The obtained off-shell form factors as well as static properties of the pion are compared with the results of other authors.
↳ hep-phnucl-th3 citations
12
Excited States from ADAPT-VQE convergence path in Many-Body Problems: application to nuclear pairing problem and $H_{4}$ molecule dissociation
Jing Zhang🇫🇷 · Denis Lacroix🇫🇷
A quantum computing algorithm is proposed to obtain low-lying excited states in many-body interacting systems. The approximate eigenstates are obtained by using a quantum space diagonalization method in a subspace of states selected from the convergence path of the ADAPT-VQE (adaptive derivative-assembled pseudo-Trotter Ansatz variational quantum eigensolver) towards the ground state of the many-body problem. This method is shown to be accurate with only a small overhead in terms of quantum resources required to get the ground state. We also show that the quantum algorithm might be used to facilitate the convergence of the ADAPT-VQE method itself. Successful applications of the technique are made to like-particle pairing as well as neutron-proton pairing. Finally, the $H_{4}$ molecule's dissociation also illustrates the technique, demonstrating its accuracy and versatility.
↳ quant-phnucl-thPLB(2025)·11 citations
13
Meson-baryon scattering lengths without annihilation diagrams to order $p^{4}$ in heavy baryon chiral perturbation theory
Jing Ou-Yang🇨🇳 · Ke Wang🇨🇳 · Bo-Lin Huang🇨🇳
We calculate the threshold $T$ matrices of the meson and baryon processes that have no annihilation diagrams: $π^{+} Σ^{+}$ , $π^{+} Ξ^{0}$ , $K^{+} p$ , $K^{+} n$ , and $K ˉ^{0} Ξ^{0}$ to the fourth order in heavy baryon chiral perturbation theory. By performing least squares and Bayesian fits to the non-physical lattice QCD data, we determine the low-energy constants through both perturbative and non-perturbative iterative methods. By using these low-energy constants, we obtain the physical scattering lengths in these fits. The convergence behavior is not good across all channels in the perturbative method. The scattering lengths for the five channels, obtained by taking the median values from four different fitting approaches, are $a_{π^{+} Σ^{+}} = - 0.16 \pm 0.07 fm$ , $a_{π^{+} Ξ^{0}} = - 0.04 \pm 0.04 fm$ , $a_{K^{+} p} = - 0.41 \pm 0.11 fm$ , $a_{K^{+} n} = - 0.19 \pm 0.10 fm$ , and $a_{K ˉ^{0} Ξ^{0}} = - 0.30 \pm 0.07 fm$ , where the uncertainties are conservatively estimated by taking the maximum deviation between the median and extreme values of the statistical errors.
↳ hep-phhep-latnucl-exnucl-thPRD(2025)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE