Nuclear Theory·nucl-th

Tuesday·August 12, 2025

17 papers—9 primary·8 cross-listed

10
[Submitted on 7 Aug 2025] (cross-list from hep-ph)
Inclusion of the Longitudinal Momentum-Transfer Component and Kinematic Factors in a diffraction approach for H(d,p)X Reactions
Ya. D. Krivenko-Emetov · B. I. Sidorenko
In this work, within the framework of the Glauber-Sitenko approximation, an analysis of the differential cross section for deuteron breakup into a proton in the reaction H(d,p)X is presented. The study is carried out using various parameterizations of the deuteron wave function, including the single-Gaussian parametrization, the multi-Gaussian K2 parametrization, and models based on the Av18 and NijmI nucleon-nucleon potentials. Special attention is given to the effects of small longitudinal components of the transferred momentum (Qz < 0.5 GeV/c) and the transverse momentum of the proton-neutron pair (p_perp < 0.5 GeV/c) in the anti-laboratory reference frame. The results are compared with experimental data, particularly in the region of longitudinal momenta p\_3 = 0.25-0.5 GeV/c, where quark effects are expected to manifest. Preliminary estimates show a decrease in the cross section with increasing transverse momentum, as well as a relatively small shift (and growth) of the cross-section maximum due to the inclusion of the longitudinal component Qz.
Comments:
35 pages, 16 figures(Presented at the XXXII Annual Scientific Conference of the Institute for Nuclear Research, Kyiv, May 26-30, 2025)
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2508.06579 [pdf]
Nucl.Phys.Atom.Energy(2026)·1 citation
11
[Submitted on 10 Aug 2025] (cross-list from hep-ph)
Constraints on the Variation of the QCD Interaction Scale $Λ_{QCD}$
V. V. Flambaum🇦🇺 · A. J. Mansour🇦🇺
Laboratory and astrophysical tests of ''constant variation'' have so far concentrated on the dimensionless fine-structure constant $α$ and on the electron or quark mass ratios $X_{e, q} = m_{e, q} / Λ_{QCD}$ , treating the QCD scale $Λ_{QCD}$ as unchangeable. Certain beyond Standard Model frameworks, most notably those with a dark matter or dark energy scalar field $ϕ$ coupling with the gluon field, would make $Λ_{QCD}$ itself time dependent while leaving $α$ and the electron mass untouched. Under the minimal assumption that this gluonic channel is the sole $ϕ$ interaction, we recast state-of-the-art atomic clock comparisons into $Λ ˙_{QCD} / Λ_{QCD} = (3.2 \pm 3.5) \times 1 0^{- 17} yr^{- 1}$ limits, translate the isotope yields of the 1.8-Gyr-old Oklo natural reactor into a complementary geophysical limit of $∣ δ Λ_{QCD} / Λ_{QCD} ∣ < 2 \times 1 0^{- 9}$ over that time span, corresponding to the linear drift limit $∣ Λ ˙_{QCD} / Λ_{QCD} ∣ < 1 \times 1 0^{- 18} yr^{- 1}$ , and show that the proposed $8.4$ eV $^{229}$ Th nuclear clock would amplify a putative $Λ_{QCD}$ drift by four orders of magnitude compared with present atomic clocks. We also obtain constraints from quasar absorption spectra and Big Bang Nucleosynthesis data.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Nuclear Theory (nucl-th); Atomic Physics (physics.atom-ph)
arXiv:
2508.07266 [pdf]
JHEP(2025)·1 citation
12
[Submitted on 10 Aug 2025] (cross-list from hep-ph)
Puzzle for the Vector Meson Threshold Photoproduction
Igor Strakovsky (GWU)🇺🇸
High-statistics total cross sections for the vector meson photoproduction at the threshold: $γ p \to ω p$ (from A2 at MAMI, ELPH, and CBELSA/TAPS), $γ p \to ϕp$ (from CLAS and LEPS), and $γ p \to J / ψ p$ (from GlueX) allow one to extract the absolute value of vector meson nucleon scattering length using Vector Meson Dominance (VMD) model. The ``young'' vector meson hypothesis may explain the fact that the obtained scattering length value for the nucleon $ϕ$ -meson compared to the typical hadron size of approximately $\sim 1 fm$ indicates that the proton is more transparent for the $ϕ$ -meson compared to the $ω$ -meson and is much less transparent than the $J / ψ$ -meson. The extended analysis of $Υ$ -meson photoproduction using quasi-data from the QCD approach is in perfect agreement with the light-meson findings using experimental data. Future high-quality experiments by EIC and EicC will have the opportunity to evaluate cases for $J / ψ$ - and $Υ$ -mesons. It allows one to understand the dynamics of $c c ˉ$ and $b b ˉ$ production at the threshold. The ability of J-PARC to measure $π^{-} p \to ϕ n$ and $π^{-} p \to J / ψ n$ , which are free from the VMD model, is considered.
Comments:
9 pages, 4 figures, 1 table; Contribution to: HADRON 2025 Proceedings
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2508.07338 [pdf]
PoS(2025)·0 citations
13
[Submitted on 10 Aug 2025] (cross-list from cond-mat.quant-gas)
Particle-hole origin of thermal beating in dipole-compression modes of a 1D Bose gas
Caroline Mauron · Karen V. Kheruntsyan · Giulia De Rosi
Using generalized hydrodynamics, we study the thermal behavior of dipole-compression collective oscillations in a harmonically trapped one-dimensional (1D) Bose gas across the crossover from weak to strong repulsive contact interactions. A key scale controlling this behavior is the temperature of the hole-induced anomaly, associated with the thermal population of hole excitations. In contrast to classical hydrodynamics, which predicts a single oscillation mode, we find a beating signal composed of two frequencies. As the temperature increases, both frequencies evolve from the low-temperature phononic hydrodynamic regime toward the collisionless limit around the anomaly temperature, without saturating at the values expected in the high-temperature collisional hydrodynamic regime. The lower frequency originates from hole excitations and is associated to low-energy oscillations, while the higher frequency emerges from particle excitations and corresponds to the dipole-compression mode. The thermal evolution of the relative excitation strengths of the two frequencies reflects the changing population imbalance between particle and hole spectral states across the anomaly. Our results reveal direct connections between excitations, thermodynamics, correlations, dynamics, and interparticle collisions, and may prove relevant to other atomic, nuclear, solid-state, electronic, and spin systems exhibiting similar anomalies or thermal second-order phase transitions.
Comments:
Main Text: 5 pages, 2 figures, 1 table; Appendices: 3 pages, 2 figures, 1 table; Supplemental Material: 2 pages
Subjects:
Quantum Gases (cond-mat.quant-gas); Superconductivity (cond-mat.supr-con); nlin.SI (nlin.SI); Nuclear Theory (nucl-th)
arXiv:
2508.07459 [pdf]
PRResearch(2026)·0 citations
14
[Submitted on 11 Aug 2025] (cross-list from hep-lat)
Leading-Order QCD Equation of State in Strong Magnetic Fields at Nonzero Baryon Chemical Potential
Heng-Tong Ding🇨🇳 · Jin-Biao Gu🇨🇳 · Arpith Kumar🇨🇳 · Sheng-Tai Li🇨🇳
We present continuum-estimated $(2 + 1)$ -flavor lattice QCD results for the leading-order Taylor expansion coefficients of the equation of state in strong magnetic fields and at nonzero baryon chemical potential. Simulations employ the highly improved staggered quark (HISQ) action with physical pion masses on lattices of temporal extent $N_{τ} = 8, 12$ , covering $145 ≲ T ≲ 165 MeV$ and $e B ≲ 0.8 GeV^{2}$ , imposing strangeness neutrality with baseline results at electric charge to baryon number ratio $r = 0.4$ . We determine the $T$ -- $e B$ dependence of $q_{1}$ and $s_{1}$ (electric charge and strangeness chemical potential ratios), pressure coefficient $P_{2}$ , baryon number density coefficient $N_{1}^{B}$ , and energy-like coefficients $Θ_{2}$ (trace anomaly), $ϵ_{2}$ (energy density), and $σ_{2}$ (entropy density). Magnetic fields induce temperature-band crossings for $q_{1}$ and $P_{2}$ and non-monotonic structures in the energy-like coefficients, with $Θ_{2}$ at strong fields possibly vanishing or turning negative at higher $T$ , indicating dominance of the pressure term over the energy contribution. We also examine the $r$ -dependence, finding that $r = 0$ (charge-neutral matter) shows the most muted magnetic-field enhancement of $P_{2}$ despite larger $∣ q_{1} ∣$ , providing a useful reference for neutron-star-like conditions. Comparisons with the hadron resonance gas (HRG) model show qualitative agreement at low $T$ and weak $e B$ , with clear deviations near the crossover and at strong fields. These results provide useful input for constraining models and effective theories of QCD matter in strong magnetic fields at finite baryon density.
Comments:
29 pages, 10 figures, 5 tables
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2508.07532 [pdf]
PRD(2025)·10 citations
15
[Submitted on 11 Aug 2025] (cross-list from hep-ph)
Vector meson dominance in photon structure functions at small $x$ from holography
Wei Gao🇨🇳 · Siming Liu🇨🇳 · Wenbin Lin🇨🇳 · Akira Watanabe🇯🇵
We investigate the photon structure functions via the photon-photon and photon-vector meson scattering within the framework of holographic QCD, focusing on the small Bjorken $x$ region and assuming that the Pomeron exchange dominates. The quasi-real photon structure functions are formulated as the convolution of the known U(1) vector field wave function with the Brower-Polchinski-Strassler-Tan (BPST) Pomeron exchange kernel in the five-dimensional AdS space. Assuming the vector meson dominance, the photon structure functions can be calculated in a different way with the BPST kernel and vector meson gravitational form factor, which can be obtained in a bottom-up AdS/QCD model, for the Pomeron-vector meson coupling. It is shown that the obtained $F_{2}$ structure functions in the both ways agree with the experimental data, which implies the realization of the vector meson dominance within the present model setup. Calculations for the longitudinal structure function and the longitudinal-to-transverse ratio are also presented.
Comments:
13 pages, 5 figures, version accepted for publication in Phys. Rev. D
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2508.07791 [pdf]
PRD(2025)·0 citations
16
[Submitted on 11 Aug 2025] (cross-list from hep-lat)
Topological Strings in SU(3) Gauge Theory at Finite Temperature
Sanatan Digal🇮🇳 · Vinod Mamale🇮🇳 · Sumit Shaw🇮🇳
We investigate string configurations in the deconfined phase of SU(3) gauge theory, which arise from the spontaneous breaking of the $Z_{3}$ center symmetry. These configurations form at the junctions of domain walls of the theory. The complex phase of the Polyakov loop changes by multiples of $2 π$ on large spatial loops around the string, rendering them topologically stable. Using the Monte Carlo simulations of the partition function, we compute the free energy associated with these configurations. The simulations are performed on lattices with spatial dimensions $N_{x, y} = 60, N_{z} = 4$ , and temporal extent $N_{τ} = 2$ . Our results show that the free energy of the $Z_{3} -$ strings is dominated by the domain walls. Further near the transition point, thermal fluctuations cause the decay of domain walls as well as the $Z_{3}$ strings into confined-deconfined interfaces.
Comments:
9 pages, 9 figures
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2508.07919 [pdf]
PRD(2026)·2 citations
17
[Submitted on 11 Aug 2025] (cross-list from hep-ph)
Chiral enhancement in soft-photon bremsstrahlung and charge asymmetry in low-energy lepton-proton scattering
Bhoomika Das🇮🇳 · Rakshanda Goswami🇮🇳 · Pulak Talukdar🇮🇳 · Udit Raha🇮🇳 · Fred Myhrer🇺🇸
We carry out a Lorentz gauge evaluation of the single-soft photon bremsstrahlung radiative corrections to the unpolarized elastic lepton-proton scattering cross section at low energies using the framework of heavy baryon chiral effective field theory (HB $χ$ PT). We systematically incorporate all next-to-leading order [i.e., $O (α^{3} / M)$ ] contributions to the cross section arising from radiative and proton's low-energy recoil effects. An important component of the soft-photon bremsstrahlung corrections arises from the interference between lepton and proton bremsstrahlung processes, which are characterized as charge-odd. We identify a class of Feynman diagrams involving the final-state radiating proton that induces a chiral enhancement, thereby modifying the naive amplitude hierarchy based on the standard chiral power-counting scheme. The recently derived HB $χ$ PT result for the analytically computed exact two-photon exchange (TPE) counterpart at NLO is combined with our charge-odd soft-photon bremsstrahlung contribution to yield the complete charge-odd radiative correction. By incorporating the leading hadronic correction to the leading order Born one-photon exchange (OPE) process within the charge-even radiative correction, we obtain a prediction for the charge asymmetry observable, which can be compared with forthcoming MUSE data on elastic lepton-anti-lepton scattering off the proton. In all our calculations, we use finite lepton masses.
Comments:
47 pages with 15 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2508.08104 [pdf]
PRD(2026)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE