Nuclear Theory·nucl-th

Tuesday·June 2, 2026

19 papers—10 primary·9 cross-listed

01
[Submitted on 30 May 2026]
Coupled nuclear and leptonic longitudinal collective modes in neutron star matter : a covariant Vlasov approach
Aziz Rabhi · Olfa Boukari · Sidney S. Avancini · Constança Providência
A covariant relativistic approach based on the Vlasov equation is used to study collective modes in neutron-star matter. The analysis is carried out within relativistic mean-field models describing charge-neutral and $β$ -equilibrated matter composed of neutrons, protons, electrons, and muons. We investigate the conditions under which nuclear collective excitations couple to electron and muon plasmon modes, a phenomenon relevant for neutron stars and supernova matter. The study is undertaken considering relativistic mean field models with different isoscalar and isovector properties. It is shown that the nuclear-leptonic coupling can be sufficiently strong to modify the onset of nuclear collective modes and to affect their isoscalar or isovector character.
Comments:
15 pages, 9 figures; submitted to Phys Rev. C
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2606.00810 [pdf]
0 citations
02
[Submitted on 31 May 2026]
Examination of the $α$ -cluster breaking in the four $0^{+}$ bands of $^{12}$ C with the variation of multiple bases of the antisymmetrized molecular dynamics
Takayuki Myo
I investigate $^{12}$ C, particularly the four kinds of the $0^{+}$ bands with various types of the $3 α$ configurations. These states are obtained in the variation of the multiple bases of the antisymmetrized molecular dynamics, where the bases are optimized simultaneously in the variation of the total energy. In the $0_{2}^{+}$ Hoyle state and the $0_{3}^{+}$ linear-chain state, I confirm a mixture of the $α$ -cluster breaking of the $s$ -wave configuration with contributions from the spin-orbit force, while the $0_{4}^{+}$ state exhibits a relatively pure $3 α$ cluster state characterized by a large radius. The $2_{2 - 4}^{+}$ and $4_{2 - 4}^{+}$ states also tend to be the pure $3 α$ cluster states. The monopole transitions between the $0_{2}^{+}$ and $0_{4}^{+}$ bands exhibit large values, suggesting breathing mode of the $3 α$ states in the $0_{4}^{+}$ band. This conclusion aligns with the predictions of the $3 α$ models with an $α$ condensate and also with a neural network, although the order of the $0_{3}^{+}$ and $0_{4}^{+}$ bands is reversed in the present results due to the attraction of the spin-orbit force.
Comments:
16 pages, 11 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2606.01054 [pdf]
PRC(2026)·0 citations
03
[Submitted on 31 May 2026]
Shape evolution of krypton isotopes calculated with axially deformed relativistic Hartree-Bogoliubov approach
Zi Xin Liu · Yi Hua Lam · Peter Ring
We perform a systematic study of the structure and properties of the krypton isotopic chain including both even-even and odd- $A$ nuclei based on the axially deformed relativistic Hartree-Bogoliubov approach. Five effective interactions of three families of covariant density functionals, i.e., PC-L3R, DD-PCX, DD-PC1, DD-MEX, and DD-ME2, are employed to calculate potential energy surfaces of krypton isotopes. $^{74, 75}$ Kr and $^{90, 91, 92}$ Kr are determined as typical candidates of shape coexistence. The potential surfaces originating from the PC-L3R, DD-PCX, and DD-MEX interactions exhibit an abrupt shape transition from oblate to prolate for $^{73 - 74}$ Kr, whereas DD-PC1 and DD-ME2 preserve an oblate ground-state shape. Such discrepancies are attributed to the occupations of single-particle levels at the vicinity of the Fermi surface described by these functionals. Moreover, the comparison between spherical and deformed calculations verifies the indispensability of deformation degrees of freedom in this region. The consideration of deformation effects improves the description of two-neutron separation energies, of which its evolution clearly demonstrates the $N = 50$ and $82$ shell closures. Interestingly, PC-L3R predicts a more extended two-neutron drip line up to $^{132}$ Kr, in agreement with the NL3* and PC-PK1 nonlinear effective interactions, whereas other functionals estimate a rather short isotopic chain up to $^{119}$ Kr. This anomalous extension implies a significant softening or even collapse of the traditional $N = 82$ shell closure near the neutron-rich drip line, highlighting the need for future studies based on triaxial deformation and beyond-mean-field correlations in this nuclear region.
Comments:
11 pages, 7 figures (colorblind-friendly colors), 2 tables
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2606.01253 [pdf]
0 citations
04
[Submitted on 1 Jun 2026]
A semi-classical study of muon-enhanced proton-boron-11 fusion
Hong-Yi Wang · Ming-Yu Chen · Hao-Le Ma · Zhu-Fang Cui
A recent theoretical study has suggested that muons can enhance proton-boron-11 (p- $^{11}$ B) reaction cross-section by several orders of magnitude in the low-energy regime. In this work, we investigate this reaction process using a semi-classical treatment, that is, a muon and a proton first form a muonic hydrogen atom p $μ$ , which subsequently collides with a $^{11}$ B nucleus. During the collision, the p $μ$ atom approaches the $^{11}$ B nucleus and is then repelled by the Coulomb repulsive potential. At the distance of closest approach between the proton and the $^{11}$ B nuclei in this classical scattering process -- namely, the classical turning point -- quantum tunneling through the Coulomb barrier can occur, allowing the proton to penetrate into the range of the nuclear force of the $^{11}$ B and trigger the fusion reaction. We determine the turning point statistically by using the classical trajectory Monte Carlo method, where the initial phase-space distributions of the proton and muon are sampled from the ground-state microcanonical distribution. Our results show that, compared with the bare-nucleus case, the reaction cross-section is enhanced by several orders of magnitude in the low-energy region. A comparison with the static charge-shielding treatment reveals certain differences; however, both approaches demonstrate that the catalytic effect of the muon can significantly enhance the low-energy p- $^{11}$ B reaction cross-section.
Comments:
8 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex); Plasma Physics (physics.plasm-ph)
arXiv:
2606.01551 [pdf]
0 citations
05
[Submitted on 1 Jun 2026]
Quantum dominance of coherent bremsstrahlung in $^{124}$ Sn + $^{124}$ Sn scattering at 25 MeV/u
Sergei P. Maydanyuk (1 and 2)🇨🇳 · Ju-Jun Xie (1, 3 and 4)🇨🇳 · Peng-Ming Zhang (5)🇨🇳 · Li-Ping Zou (6) ((1) Southern Center for Nuclear-Science Theory (SCNT), Institute of Modern Physics, Chinese Academy of Sciences, Huizhou 516000, China, (2) Institute for Nuclear Research, National Academy of Sciences of Ukraine, Kyiv 03680, Ukraine, (3) Heavy Ion Science and Technology Key Laboratory, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China, (4) School of Nuclear Sciences and Technology, University of Chinese Academy of Sciences, Beijing 101408, China, (5) School of Physics and Astronomy, Sun Yat-Sen University, Zhuhai 519082, China, (6) Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-Sen University, Zhuhai 519082, China)🇨🇳
We present quantum-mechanical calculations of bremsstrahlung in the $^{124}$ Sn + $^{124}$ Sn at 25 MeV/u reproducing the measured photon spectrum over the full energy range. For the first time, we quantitatively determine the incoherent-to-coherent ratio in the photon spectrum. This ratio is extremely small, ranging from $1 0^{- 11}$ to $1 0^{- 4}$ , which demonstrates that coherent emission dominates throughout the measured energy range. This behavior is in sharp contrast to proton-nucleus scattering, where incoherent emission dominates because of the leading role of nucleon magnetic moments. This contrast is illustrated by the TAPS Collaboration data for $p +^{197} Au$ collisions at a proton beam energy of 190 MeV, where the corresponding ratio reaches $1 0^{3}$ - $1 0^{5}$ . We find that incoherent-to-coherent ratios explain the difference between the two spectra in unified picture: (1) In proton--nucleus scattering, the spectrum contains a pronounced hump, (2) In $^{124}$ Sn + $^{124}$ Sn scattering, the spectrum decreases monotonically and has a nearly logarithmic shape. Our results identify a previously unexplored quantum regime of bremsstrahlung emission in nuclear reactions and open a new route for studying coherent effects in heavy-ion collisions.
Comments:
6 pages, 2 captured figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex)
arXiv:
2606.01623 [pdf]
0 citations
06
[Submitted on 1 Jun 2026]
Hydrodynamics without a relaxation gap: memory effects, nonlocality, and superdiffusion
Lorenzo Gavassino🇬🇧 · Sukanya Mitra🇮🇳 · Rajeev Singh🇷🇴
By studying a simple model of relativistic particles propagating through a background medium with an energy-dependent relaxation time that is unbounded from above, we investigate how long-term memory obstructs the emergence of local hydrodynamics in systems with a gapless non-hydrodynamic sector. In the RTA matching frame, we show that the full gradient expansion is generically divergent in most flows, even for Fourier modes, and that any resummation necessarily retains an infinite set of slow non-hydrodynamic degrees of freedom. The divergence of the gradient expansion therefore reflects a more fundamental breakdown of hydrodynamic locality caused by persistent non-hydrodynamic memory. We finally show that sufficiently singular relaxation spectra can invalidate ordinary diffusion itself. In these regimes, the diffusivity diverges, and the late-time dynamics become superdiffusive, governed by intrinsically nonlocal constitutive relations.
Comments:
11 pages, 2 figures, published in PRD (see https://journals.aps.org/prd/abstract/10.1103/9362-8gmq)
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Theory (hep-th)
arXiv:
2606.01805 [pdf]
PRD(2026)·0 citations
07
[Submitted on 1 Jun 2026]
Radial-flow fluctuations in the geometrical-scaling framework
Takeshi Osada🇯🇵
We discuss radial-flow fluctuations using the $p_{T}$ -differential measure $v_0(p_{\rm T})$, together with its $p_{T}$ -integrated counterpart $v_0$, within the framework of geometrical scaling (GS), where the saturation momentum scale provides the characteristic scale for particle production. We show that the GS framework leads to results similar to those obtained from the momentum-rescaling model proposed by Jiangyong Jia. In the GS picture, event-by-event spectral fluctuations are governed by fluctuations of the saturation momentum scale; consequently, the single-mode ansatz introduced in Jia's model emerges naturally. We also show that the GS picture suggests a possible connection between transverse-momentum correlations and fluctuations of the emission region, which may be probed through Hanbury Brown and Twiss (HBT) analyses. Using the string percolation model, which is closely related to GS, we estimate the multiplicity dependence of radial-flow fluctuations and propose the scaled quantity $A_{0} (N_{Δ y}) \equiv v_{0}^{2} N_{Δ y}$ , with $N_{Δ y} = (d N / d y) Δ y$ , as a diagnostic observable for testing the role of effective flux-tube fluctuations.
Comments:
8 pages, 1 figure
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2606.02108 [pdf]
1 citation
08
[Submitted on 1 Jun 2026]
Hypernucleus production in p+Au reactions at the FAIR facility
Nitikorn Jaingarm🇹🇭 · Pornrad Srisawad🇹🇭 · Christoph Herold🇹🇭 · Ayut Limphirat🇹🇭 · Jan Steinheimer🇩🇪 · Marcus Bleicher🇩🇪
We explore the production of hypernuclei in p+Au reactions using the UrQMD model accompanied by a standard phase space coalescence model. We focus on the proton beam energy range of $E_{lab} = 5 - 30$ GeV as this energy range will be investigated by the CBM-experiment at the upcoming FAIR facility. Starting from proton, $Λ$ , $Σ$ , $Ξ$ and $Ω$ production, we predict the yields, rapidity and transverse momentum distributions of $_{Λ}^{3} H$ , $_{Λ}^{4} H$ , $Ξ$ N and $Ξ$ NN hypernuclei. We conclude that the production rates of novel multi-strange hypernuclei are well within the reach of the CBM-experiment.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2606.02191 [pdf]
0 citations
09
[Submitted on 1 Jun 2026]
The spectrum of $^{18}$ O in terms of the multiconfigurational dynamical symmetry
Gábor Riczu · Chandra Sekhar Panda · Géza Lévai · József Cseh
Background: The experimental study of the $^{6}$ Li-transfer reaction and alpha-scattering resulted in a rich spectrum of $^{18}$ O, including some strong indication for band structure. Different configurations are proposed for the structural interpretation of different energy domains. Purpose: We intend to investigate whether a uniform description is possible for the complete spectrum, including the high-lying states from scattering measurement. Methods: We apply the multiconfigurational dynamical symmetry for the determination of the shape isomers and for the calculation of the spectrum obtained from different reactions. Results: The shape isomers of $^{18}$ O is obtained from the study of the stability and self-consistency of the SU(3) symmetry, which is in the intersection of the shell and different cluster configurations. The $^{14}$ C+ $^{4}$ He spectrum is calculated, and its connection to other configurations is revealed. A very simple Hamiltonian is applied, including only a harmonic oscillator term, a quadrupole interaction and an $L^{2}$ term. Conclusions: The spectrum (from the ground state up to the high-lying states) can be reasonably well described by a $^{14}$ C+ $^{4}$ He cluster configuration. All the state allows the $^{12}$ C+ $2 n$ + $^{4}$ He clusterization as well, and has definite shell model content. For the lowest-lying three bands the shell configuration is unique, and the overlap of the shell and the different cluster configurations is 100%.
Comments:
11 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2606.02270 [pdf]
0 citations
10
[Submitted on 1 Jun 2026]
Quantum Symmetry Restoration and Emergent Effective Deformation in Relativistic Heavy-Ion Collisions
Hao-jie Xu🇨🇳 · Qun Wang🇨🇳
Classically deformed nuclear geometries are commonly employed in standard descriptions of relativistic collisions between two even-even nuclei, despite the fact that their exact ground states are rotationally invariant $0^{+}$ states. In this paper, we formulate the collision geometry directly from the eikonal scattering matrix based on a nonorthogonal Generator Coordinate Method construction of rotationally invariant ground states. In the optical limit, using a localized transported-density approximation for the collision-channel one-body response, rotational overlap localization generates an effective one-body density associated with the scattering process. Within this approximation, using the Gaussian Overlap Approximation and its heat-kernel representation, we show that rotational symmetry restoration acts as a geometric low-pass filter which exponentially suppresses effective deformation modes. The classical rigid-rotor limit is recovered for large intrinsic angular momentum fluctuations. We establish a microscopic framework connecting rotational symmetry restoration, collective overlap localization, and the effective deformation geometries of nuclei in high energy collisions.
Comments:
9 pages, 1 figure
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2606.02412 [pdf]
0 citations
11
[Submitted on 29 May 2026] (cross-list from nucl-ex)
Dependence of two-particle azimuthal correlations on the forward rapidity gap width in pPb collisions at $s_{NN}$ = 8.16 TeV
CMS Collaboration
One of the most striking features of relativistic heavy ion collisions is the presence of collective flow of thousands of produced particles. This flow can be characterized by the Fourier coefficients ( $V_{n Δ}$ ) of the azimuthal angular distributions of charged particles, and its existence can be explained by the formation of a quark gluon plasma, which behaves as a fluid. Surprisingly, the angular distributions of particles from very small systems such as proton-lead (pPb), proton-proton (pp), electron-positron, and photon-proton ( $γ$ p) collisions also exhibit non-zero Fourier coefficients, raising the question of whether collective flow is present. This paper presents measurements of $V_{n Δ}$ from a sample of pPb events at $s_{NN}$ = 8.16 TeV that are enriched in photon-lead ( $γ$ Pb) and pomeron-lead ( $I P$ Pb) interactions by requiring no particles in the proton-going region. Measurements are made as a function of the forward rapidity gap width (the rapidity range in which no particles are found), the transverse momentum of the particles, and the multiplicity of particles in the event. The results are compared to previous measurements of pp, pPb, and $γ$ p+ $I P$ p events as well as modern event generators.
Comments:
Submitted to Physical Review C. All figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/HIN-22-004 (CMS Public Pages)
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2606.00171 [pdf]
0 citations
12
[Submitted on 30 May 2026] (cross-list from nucl-ex)
Investigation of the onset of deconfinement with the NA61/SHINE experiment
A. Bazgir🇵🇱
High-energy heavy-ion collisions provide a unique framework for studying the phase transition of strongly interacting matter. The NA61/SHINE experiment, located in the North Area of CERN's SPS, is a fixed-target facility designed to perform a systematic exploration of the QCD phase diagram. This is achieved through a two-dimensional scan that varies both the beam momentum (from 13A to 150/158A GeV/c) and the size of the colliding systems (p+p, p+Pb, Be+Be, Ar+Sc, Xe+La, Pb+Pb, O+O). Such a wide scan enables detailed studies of how collision dynamics evolve with system size and energy. A central objective of the NA61/SHINE research program is to investigate the onset of deconfinement - the transition from hadronic matter to a quark-gluon plasma (QGP) - by analyzing observables such as the strangeness-to-entropy ratio, where entropy is proportional to pion yields. According to the Statistical Model of the Early Stage (SMES), this ratio is expected to exhibit a horn-like structure within the SPS energy range. This article discusses the theoretical framework of the SMES, its assumptions, and compares recent NA61/SHINE results with other experimental data worldwide, contributing to a deeper understanding of the QCD phase transition.
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2606.00597 [pdf]
0 citations
13
[Submitted on 30 May 2026] (cross-list from physics.data-an)
Proton High-Order Cumulants in Au+Au Collisions at High Baryon Density from JAM with a Centrality-Independent Framework
Yongcong Xu🇨🇳 · Zhaohui Wang🇨🇳 · Yu Zhang🇨🇳 · Xiaofeng Luo🇨🇳
The event-by-event higher-order cumulants of conserved quantities such as net-baryon, net-electric charge, and net-strangeness in heavy-ion collisions have been extensively utilized in experimental searches for the QCD critical point, notably in the RHIC-STAR experiment. In this study, we conduct a systematic analysis of higher-order cumulants of proton number distributions in Au+Au collisions at center-of-mass energies of $s_{NN} = 3.2$ , $3.5$ , $3.9$ , and $4.5$ GeV using the JAM model. We calculate cumulants, factorial cumulants, and their ratios using a novel method, Centrality-Independent Genuine Cumulant Analysis fRamework (CIGAR), which effectively eliminates initial volume fluctuations. We comprehensively compare the CIGAR method with the traditional Centrality Bin Width Correction (CBWC) method. In addition, the effect of spectators on cumulant is systematically investigated. Our results provide a dynamic non-critical baseline in the high-baryon-density regime which is crucial for QCD critical point searches in heavy-ion collisions.
Comments:
10 pages, 8 figures
Subjects:
Data Analysis, Statistics and Probability (physics.data-an); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2606.00786 [pdf]
0 citations
14
[Submitted on 30 May 2026] (cross-list from cond-mat.quant-gas)
Three- and four-boson systems expanded around the unitarity limit: Application to $^{4}$ He
Feng Wu🇫🇷 · Xincheng Lin🇺🇸 · Ubirajara van Kolck🇫🇷 · Sebastian König🇺🇸
The three- and four-boson systems with a large scattering length and a short effective range in the two-body sector are studied in the framework of Short-Range Effective Field Theory. The starting point (leading order) of the EFT is taken to be the universal unitarity limit, where the two-body sector is parameter-free and only one three-body parameter enters. In this limit, physical systems manifests discrete scale invariance. Deviations from universality arising from finite scattering-length and effective-range corrections, as well as a four-body force required by renormalization, are included perturbatively at next-to-leading order. The three-body ground state and its associated four-body ground and first-excited states are studied using the Faddeev-Yakubovsky formalism and a complementary diagrammatic approach. By employing techniques to remove contributions from deep trimers in tetramer calculations, we extend our analysis to larger cutoffs than previously accessible within the FY approach. Our results for binding energies and radii of $^{4}$ He three- and four-atom systems converge well to results obtained with sophisticated phenomenological potentials. These successes suggest that the physics of $^{4}$ He atomic clusters is governed by only small deviations from discrete scale invariance.
Comments:
29 pages, 20 figures
Subjects:
Quantum Gases (cond-mat.quant-gas); Nuclear Theory (nucl-th); Atomic Physics (physics.atom-ph)
arXiv:
2606.00854 [pdf]
1 citation
15
[Submitted on 31 May 2026] (cross-list from hep-th)
Pseudo-Gauge Stabilizers and Fibration Structure of the Cooper--Frye Map at Freeze-Out
Jiahua Tian🇨🇳
We study the pseudo-gauge transformation (PGT) freedom at freeze-out in relativistic spin hydrodynamics. The Cooper--Frye map is shown to factor through the quotient of freeze-out data by a universal stabilizer, yielding a stratified fibration over the space of thermodynamic Lagrange multipliers. This classifies observables into base and fiber types, bounds the number of independent PGT-sensitive observables by the family-restricted fiber dimension, and implies cross-observable consistency relations. Applied to heavy-ion polarization data, the fibration structure provides a structural interpretation of the tension between $Λ$ polarization and $ϕ$ -meson spin alignment as evidence that the vorticity-dominated response sector may need to be enlarged with local field-correlation data. We show that Weyl-anomaly-induced currents studied recently are classified as base observables and recover the known Belinfante--canonical obstruction $Ω_{ab} \neq = ϖ_{ab}$ from the stabilizer condition.
Subjects:
High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2606.01429 [pdf]
0 citations
16
[Submitted on 1 Jun 2026] (cross-list from hep-ph)
Azimuthal decorrelation in diffractive dijet production
Ding Yu Shao🇨🇳 · Yu Shi🇨🇳 · Cheng Zhang🇨🇳 · Jian Zhou🇨🇳 · Ya-jin Zhou🇨🇳
We calculate the azimuthal angular decorrelation of diffractive dijets in ultra-peripheral heavy-ion, $e p$ , and $e A$ collisions to probe non-perturbative diffractive transverse momentum-dependent distributions. Focusing on the dominant semi-inclusive channel with an unobserved semi-hard gluon, we perform an all-order resummation of soft gluon emissions for the transverse energy-energy correlator observable, accounting for both initial and final state radiation. We also analyze heavy-quark pair production and demonstrate the sensitivity of the decorrelation to the jet axis definition. Finally, we provide numerical predictions for relevant kinematics at LHC UPCs, HERA, and the future EIC. Our results demonstrate that the acoplanarity of diffractive dijet production could serve as a promising probe of diffractive transverse momentum-dependent distributions.
Comments:
29 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2606.02230 [pdf]
1 citation
17
[Submitted on 1 Jun 2026] (cross-list from nucl-ex)
Studies of $^{144, 148} Sm + α$ potential for the $p$ -process nucleosynthesis
C. Soto🇫🇷 · C. Ducoin🇫🇷 · N. Millard-Pinard🇫🇷 · B. M. Rebeiro🇫🇷 · O. Stézowski🇫🇷 · N. de Séréville🇫🇷 · F. Hammache🇫🇷 · A. Chalil🇫🇷 · Y. Demane🇫🇷 · C. Bachelet🇫🇷 · J.-C. Thomas🇫🇷 · M. Assié🇫🇷 and 12 other authors
Nucleosynthesis reaction networks leading to $p$ -nuclei involve a combination of different types of photodisintegration and capture reactions, as well as $β^{+}$ decays or electron captures. Photodisintegration reactions involving $α$ particles present a particular interest as they serve as branching points of the reaction networks. The cross sections of these reactions depend crucially on the $α$ -nucleus interaction. The $α$ optical model potential (AOMP) is determined mostly by means of experimental differential elastic scattering distributions. Several previous studies have focused on the case of $^{144} Sm$ , an intriguing $p$ -nucleus that is semi-magic with 82 neutrons. This work presents new experimental data on $α$ elastic and inelastic scattering on $^{148} Sm$ , its closest stable isotope. Isotopic effects on the description of the AOMP are studied, as well as their consequences on the prediction of $α$ -induced reaction cross sections at astrophysical energies. It is shown that the isotopic ratio for $(α, γ)$ cross sections can be multiplied up to a factor of two when these effects are included.
Comments:
Submitted to Phys. Rev. C
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2606.02266 [pdf]
0 citations
18
[Submitted on 1 Jun 2026] (cross-list from hep-ph)
Probing Pair Correlations in QCD Matter with Photon Spectra
Xingjian Lu🇨🇳 · Shuzhe Shi🇨🇳
Correlations in the phase-space distribution of partons play an important role in the initial stage of relativistic heavy-ion collisions, where the matter is dense and far from equilibrium. Photons produced in the hot medium, which predominantly originate from two-parton initial states, are sensitive to two-particle correlations in the phase-space distribution. In this work, we study how pair correlations in non-equilibrium QCD matter affect in-medium photon production. We decompose the two-particle distribution as $F_{ab} = f_{a} f_{b} + g_{ab}$ , where $g_{ab}$ is the pair correlation. Focusing on the $2 \to 2$ quark--antiquark annihilation and Compton channels, we compute the leading-logarithmic photon spectrum by expanding the single-particle distribution and pair correlation in a spectral basis, thereby accommodating a broad class of two-particle distributions. For a rotationally invariant medium, we find that relative-angle modes of the pair correlation generate sign-changing modifications to the photon spectrum, with magnitudes that can be comparable to the factorized contribution. Thus, photon spectra, although single-particle observables, can measure the momentum correlations of the emitting medium and therefore probe the early-time hydrodynamization.
Comments:
12 pages, 6 figures,
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2606.02414 [pdf]
0 citations
19
[Submitted on 1 Jun 2026] (cross-list from hep-th)
Cumulant dynamics in finite-memory diffusion
Navid Abbasi🇨🇳 · Xin An🇧🇪 · Shanjin Wu🇨🇳
Fluctuations of conserved charges are among the main proposed signatures of the quantum chromodynamics (QCD) critical point, but their interpretation requires a dynamical description of how fluctuation correlators evolve during the finite lifetime of the quark--gluon plasma (QGP) fireball. The standard baseline for this evolution is Fickian diffusion, in which the diffusive current follows the local density gradient instantaneously. This instantaneous-current limit can miss delayed-response effects when the current-relaxation time becomes comparable to the relaxation time of the relevant fluctuation modes. In this work we extend this baseline to Maxwell--Cattaneo diffusion, where the current relaxes on a finite time scale and therefore retains memory. We derive closed evolution equations for multi-point Wigner functions and convert the freezeout correlators into acceptance-dependent cumulants along representative trajectories in the QCD phase diagram. While Fickian diffusion already causes the correlators to lag behind their instantaneous equilibrium values, finite current relaxation introduces an additional memory effect beyond this diffusive lag. As a result, current memory can suppress, shift, and reshape the non-monotonic behavior of the cumulants relative to both instantaneous equilibrium and Fickian diffusion, with the most visible effects appearing in higher-order cumulants and their ratios.
Comments:
49 pages, 10 figures
Subjects:
High Energy Physics — Theory (hep-th); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2606.02446 [pdf]
0 citations

Affiliations

first authorsco-authorsvia INSPIRE