Nuclear Theory·nucl-th

Tuesday·June 17, 2025

24 papers—10 primary·14 cross-listed

01
Impact of particle production mechanisms on pseudorapidity distribution and directed flow in Au+Au and Cu+Cu collisions at $s_{N N}$ = 19.6 GeV using AMPT model
Muhammad Farhan Taseer🇨🇳 · Subhash Singha🇨🇳
The STAR experiment at the top RHIC energy has observed that the directed flow ( $v_{1}$ ) of inclusive light hadrons is independent of the collision system size at a given centrality~\cite{STAR:2008jgm}. However, recent STAR measurements indicate a system-size dependence in the $v_{1} (y)$ -slope ( $d v_{1} / d y$ ) of protons, antiprotons, and their differences ( $Δ d v_{1} / d y$ ) at a given centrality, suggesting a potential influence of baryon production and transport mechanisms~\cite{Taseer:SQM2024talk}. We have studied pseudorapidity ( $d N / d y$ ) distributions and directed flow ( $v_{1}$ and $d v_{1} / d y$ ) for pions, kaons, and protons in Au+Au and Cu+Cu collisions at $s_{N N} = 19.6$ GeV using the A Multi-Phase Transport (AMPT) model. Specifically, we investigated the influence of string junction parameters in AMPT via the PYTHIA/JETSET routines, focusing on the popcorn mechanism and string-splitting parameters, on $d N / d y$ , $d v_{1} / d y$ , and their charge-dependent splittings ( $Δ d N / d y$ and $Δ d v_{1} / d y$ ). We observe that string junction parameters can affect $d N / d y$ , $d v_{1} / d y$ , $Δ d N / d y$ , and $Δ d v_{1} / d y$ for $π$ , K, and p, and influence their system-size dependence. The effect is most prominent on the $v_{1}$ of protons, non-trivial for kaons, while the pions $v_{1}$ remain largely unchanged. These findings provide insights into the interplay between particle production mechanisms, baryon transport, and directed flow in heavy-ion collisions.
nucl-thhep-exhep-phnucl-exCPC(2025)·0 citations
02
Imprint of $α$ -Clustering on Ab Initio Correlations in Relativistic Light Ion Collisions
Hadi Mehrabpour🇨🇳
This study investigates the influence of $α$ -cluster structures in relativistic light nuclear collisions. Using a cluster framework, I extract the characteristics of the nucleonic configurations of $^{16}$ O and $^{20}$ Ne as predicted by various \textit{ab-initio} models, including Nuclear Lattice Effective Field Theory (NLEFT), Variational Monte Carlo (VMC), and the Projected Generator Coordinate Method (PGCM). Additionally, I analyze configurations derived from a three-parameter Fermi (3pF) density function. The investigation focuses on the effects of cluster parameters on two-point correlators using a rotor model for symmetric collisions ( $^{16}$ O+ $^{16}$ O and $^{20}$ Ne+ $^{20}$ Ne) and asymmetric collisions ( $^{208}$ Pb+ $^{16}$ O and $^{208}$ Pb+ $^{20}$ Ne). The cluster parameters are determined by minimizing the \textit{chi-square} statistic to align the nucleon distributions with those predicted by the aforementioned theories. The results reveal that perturbative calculations effectively capture the structural features of these nuclei, while comparisons with Monte Carlo simulations validate these findings. Furthermore, the analysis reveals distinct cluster geometries: VMC suggests tetrahedral shapes, while NLEFT, PGCM, and 3pF indicate irregular triangular pyramids. Notably, NLEFT shows a bowling pin-like $α$ cluster structure for $^{20}$ Ne. The study also identifies constraints on cluster parameters in the different oxygen structures, with a gradual increase in $ε_{2} {2}$ for the states of $α$ + $^{12}$ C. Accurate modeling of asymmetric collisions necessitates a range of nucleons from heavy spherical nuclei, leading to weighted correlators in perturbative calculations. I demonstrate consistency between perturbative calculations and Monte Carlo models, with analytical calculations providing more insights into asymmetric than symmetric collisions.
nucl-thhep-thPRC(2026)·9 citations
03
Sign-Problem-Free Nuclear Quantum Monte Carlo Simulation
Zhong-Wang Niu🇨🇳 · Bing-Nan Lu🇨🇳
Quantum Monte Carlo (QMC) methods offer exact solutions for quantum many-body systems but face severe limitations in fermionic systems like atomic nuclei due to the sign problem. While sign-problem-free QMC algorithms exist and provide valuable insights across disciplines, they have been restricted to simple models with limited quantitative predictive power. Here we overcome this barrier by developing a novel lattice nuclear force that is rigorously sign-problem-free for even-even nuclei. This interaction achieves a standard deviation of $σ = 2.932$ MeV from experimental binding energies for 76 even-even nuclei ( $N, Z \leq 28$ ), matching state-of-the-art phenomenological mean-field models. Key innovations include the first sign-problem-free implementation of spin-orbit coupling for shell evolutions and an efficient QMC-optimized framework for global parameter fitting. Using this approach, we compute binding energies from $^{4}$ He to $^{132}$ Sn with unprecedented one-thousandth level numerical precision, reproduce symmetric nuclear matter saturation, and reveal novel spin-orbit-driven clustering in light nuclei. This work transforms sign-problem-free QMC into a scalable and predictive nuclear structure tool, while establishing a high-fidelity, non-perturbative foundation for \textit{ab initio} calculations of heavy nuclei.
nucl-thhep-latPRL(2025)·20 citations
04
Evolution of energy density fluctuations in the presence of a magnetic field
Shreyansh S. Dave🇮🇳 · Subrata Pal🇮🇳
In this proceeding, we study the evolution of energy density fluctuations in the presence of a static and uniform magnetic field. By numerically solving the relativistic Boltzmann-Vlasov equation within the relaxation time approximation and performing the momentum mode analysis of different wavelength fluctuations, we show that the magnetic field increases the damping of mode oscillations. This causes a qualitative change in the fluctuations present in the system at the timescale required to achieve a local equilibrium state.
nucl-thhep-phhep-thJ.Subatomic Part.Cosmol.(2025)·0 citations
05
Application of the optimized-basis generator coordinate method to low-lying excited states of sd-shell nuclei
Moemi Matsumoto · Yusuke Tanimura · Kouichi Hagino
We apply the optimized-basis generator coordinate method (OptGCM) to sd-shell nuclei, $^{20}$ Ne, $^{24}$ Mg, and $^{28}$ Si. This method variationally optimizes both the basis Slater determinants in the generator coordinate method (GCM) and the corresponding weight coefficients. To analyze the low-lying excited states of those nuclei, we implement the angular momentum projection. With the Skyrme interaction, we show that the simultaneous optimzation of the basis functions and the weight factors lowers the energy of the excited states and at the same time leads to an appreciable effect on transition probabilities. These results highlight the effectiveness of the OptGCM method.
nucl-thPRC(2025)·1 citation
06
$0 ν β β$ decay nuclear matrix elements under Left-Right symmetric model from the spherical quasi-particle random phase approximation method with realistic force
Ri-Guang Huang🇨🇳 · You-Cai Chen🇨🇳 · Dong-Liang Fang🇨🇳
We perform the calculation of nuclear matrix elements for the neutrinoless double beta decays under a Left-Right symmetric model mediated by light neutrino, and we adopt the spherical quasi-particle random-phase approximation (QRPA) approach with realistic force. For eight nuclei: $^{76}$ Ge, $^{82}$ Se, $^{96}$ Zr, $^{100}$ Mo, $^{116}$ Cd, $^{128}$ Te, $^{130}$ Te and $^{136}$ Xe, related nuclear matrix elements are given. We analyze each term and the details of contributions of different parts are also given. For the $q$ term, we find that the weak-magnetism components of the nucleon current contribute equally as other components such as axial-vector. We also discuss the influence of short-range correlations on these NMEs. It is found that $R$ term are more sensitive to the short range correlation than other terms due to the large portion of the contribution from high exchange momenta.
nucl-thCPC(2026)·1 citation
07
Kadanoff-Baym approach to bound states in open quantum systems
Tim Neidig🇩🇪 · Marcus Bleicher🇩🇪 · Hendrik van Hees🇩🇪 · Carsten Greiner🇩🇪
In this paper, we extend the method of Kadanoff-Baym equations for open quantum systems to arbitrary kinds of systems and heat baths, either fermionic or bosonic. This includes three spacial dimensions and different potentials for the system-bath interaction or external traps. We study the quantum-mechanical formation of bound states in one and also in three dimensions with the full Kadanoff-Baym equations and compare them to more simplified approaches with and without memory effects. An in-depth examination of the thermodynamics of open systems is performed, showing perfect equilibration of the system's degrees of freedom along with a comprehensive investigation of the influence of the heat bath on the system's wave functions. The formation time, decay time and regeneration of bound states and their dependence on the temperature and coupling strength is explored We evaluate the non-equilibrium Kadanoff-Baym equations for the system particles, assuming that interactions are elastic two-particle collisions with the heat-bath particles. Finally, we describe in detail the method used to numerically solve the corresponding spatially heterogeneous integro-differential equations for the set of one-particle Green's functions.
nucl-thPRC(2025)·1 citation
08
Hot pygmy dipole strength in nickel isotopes
Amandeep Kaur · Esra Yüksel · Nils Paar
At finite temperatures, nuclear excitations are significantly modified, most notably through the emergence of additional low-energy dipole strength, which can critically impact astrophysical reaction rates. Ongoing fusion-evaporation experiments on Ni isotopes provide a unique opportunity to investigate the hot pygmy dipole strength (HPDS), underscoring the need for reliable theoretical predictions and a comprehensive understanding of this emerging phenomenon. In this work, the HPDS is investigated in Ni isotopes from $N = Z$ to neutron-rich systems ( $^{56 - 70}$ Ni) over a temperature range of $T =$ 0 $-$ 2~MeV using the finite-temperature relativistic quasiparticle random phase approximation. In neutron-rich Ni isotopes, the pygmy dipole strength at higher temperatures exceeds up to 2.5 times its value observed at zero temperature. In contrast, near $N \approx Z$ isotopes show negligible low-energy dipole strength at $T = 0$ MeV but develop a pronounced HPDS as the temperature increases. Predicted E1 energy-weighted strength ( $S_{EWS}$ ) and cumulative $B$ (E1) values for HPDS are presented across the Ni isotopic chain for various low-energy intervals and temperatures, providing essential benchmarks to support and guide experimental studies.
nucl-thPRC(2025)·1 citation
09
Constraints on $Λ N$ Effective Interactions from Mirror Hypernuclei in a Deformed Relativistic Hartree-Bogoliubov Model
Yu-Ting Rong🇨🇳 · Dan Yang🇨🇳 · Cheng-Jun Xia🇨🇳 · Ting-Ting Sun🇨🇳
We investigate the ground-state properties of four mirror hypernuclei pairs-- $_{Λ}^{10}$ Be- $_{Λ}^{10}$ B, $_{Λ}^{12}$ B- $_{Λ}^{12}$ C, $_{Λ}^{16}$ N- $_{Λ}^{16}$ O, and $_{Λ}^{40}$ K- $_{Λ}^{40}$ Ca--within the deformed relativistic Hartree-Bogoliubov framework, analyzing their connection to $Λ N$ effective interactions. Systematic calculations with eight distinct effective interactions reveal linear correlations between mirror hypernuclei in $Λ$ separation energies and charge radii. The charge symmetry breaking effects, quantified through $Λ$ separation energy differences, exhibit a positive correlation with the SU(3) flavor symmetry violation. We emphasize that constraints derived from $A = 10$ and $A = 12$ hypernuclear pairs must explicitly incorporate rotational energy correction effects. Precision measurements of the (near) spherical $A = 16$ and $A = 40$ mirror systems are proposed as critical benchmarks for refining the isospin part of the hyperon-nucleon interactions.
nucl-th2 citations
10
Two-neutrino $0^{+} \to 0^{+}$ double beta decay of $^{48} Ca$ within the DFT-NCCI framework
Jan Miśkiewicz🇵🇱 · Maciej Konieczka🇵🇱 · Wojciech Satuła🇵🇱
We present a seminal calculation of the nuclear matrix element for the two-neutrino double beta ( $2 ν β β$ ) decay of $^{48} Ca \to^{48} Ti$ using a post-Hartree-Fock (HF) Density Functional Theory-based No-Core Configuration-Interaction (DFT-NCCI) framework developed by our group [Phys. Rev. C 94, 024306 (2016)]. In the present calculation, we utilize a variant of the approach that restores rotational symmetry and mixes states projected from self-consistent mean-field configurations obtained by solving the HF equations with the density-independent local Skyrme interaction. Our calculations yield $∣ M_{2 ν β β} ∣ = 0.056 (6)$ MeV $^{- 1}$ for the nuclear matrix element describing this process. This result is in very good agreement with shell-model studies - for example, with the calculations by Horoi {\it et al.\/} [Phys. Rev. C 75, 034303 (2007)], which yielded 0.054 (0.064) MeV $^{- 1}$ for the GXPF1A (GXPF1) interactions, respectively. It is also in a reasonable agreement with the most recent experimental estimate from the review by Barabash, which is 0.068(6) MeV $^{- 1}$ , assuming quenching $q g_{A} \approx 1$ . The consistency of our prediction with the shell-model results increases our confidence in the nuclear modeling of this second-order, very rare process which is of paramount importance for further modeling of the neutrinoless double beta ( $0 ν β β$ ) decay process.
nucl-thPRC(2025)·6 citations
11
Asymmetric muon-antimuon emission from $Z^{0}$ decays: a clear magnetometer in relativistic heavy-ion collisions
Alejandro Ayala🇲🇽 · Ana Julia Mizher🇧🇷 · Javier Rendón🇲🇽
We show that a very clear signal of the presence of a strong magnetic field during the early stage of a high-energy heavy-ion collision is provided by the decay of the $Z^{0}$ into dimuon pairs. We find that the process is highly anisotropic, producing pairs mainly out of plane, as signaled by a negative value of $v_{2}$ , and leads to an antimuon transverse momentum distribution which peaks at a higher value of the transverse momentum compared to the peak of the muon transverse momentum distribution. We also show that the process does not produce a significant distortion of the $Z^{0}$ spectral function. The signal can be identified by comparing the dimuon-invariant mass and the individual muon and antimuon spectra produced in semicentral heavy-ion collisions with the corresponding scaled spectra produced in p+p collisions at the $Z^{0}$ peak.
↳ hep-phhep-exnucl-exnucl-thPRC(2026)·3 citations
12
Charge Pickup Reaction Cross Section for Neutron-Rich p-Shell Isotopes at 900A MeV
J.-C. Zhang · B.-H. Sun · I. Tanihata · S. Terashima · F. Wang · R. Kanungo · C. Scheidenberger · F. Ameil · J. Atkinson · Y. Ayyad · S. Bagchi · D. Cortina-Gil and 25 other authors
We report charge pickup reaction cross sections for 24 \textit{p}-shell isotopes, including $^{8, 9}$ Li, $^{10 - 12}$ Be, $^{10, 13 - 15}$ B, $^{12, 14 - 19}$ C and $^{14, 15, 17 - 22}$ N, measured at relativistic energies (approximately 900 $A$ MeV) on both hydrogen and carbon targets. For the first time, we reveal a universal rapid increase in the charge pickup cross sections of unstable projectiles with isospin asymmetry along several isotopic chains. The cross sections can be decoupled into distinct contributions from the mass number and isospin asymmetry of the projectile, highlighting the critical role of the latter, and can be formulated empirically.
↳ nucl-exnucl-thPRX(2025)·4 citations
13
Properties and microscopic structures of dense stellar matter in RMF models
Jia-Xing Niu🇨🇳 · Hao Sun🇨🇳 · Cheng-Jun Xia🇨🇳 · Toshiki Maruyama🇯🇵
Data tables on the equation of state (EOS) and microscopic structures for cold dense stellar matter with proton fractions $Y_{p} = 0.01$ - $0.65$ and baryon number densities $n_{b} = 1 0^{- 8}$ - $2 fm^{- 3}$ are obtained adopting 13 different relativistic density functionals, i.e., NL3, PK1, PK1r, GM1, MTVTC, DD-LZ1, PKDD, DD-ME2, TW99, DD-MEX, DD-MEX1, DD-MEX2, and DD-MEY. The EOSs of dense stellar matter inside neutron stars with baryon number densities $n_{b} = 7.6 \times 1 0^{- 11}$ - $2 fm^{- 3}$ are obtained as well fulfilling $β$ -stability condition. In general, the dense stellar matter exhibits droplet phase at $n_{b} ≲ 0.015 fm^{- 3}$ , while more exotic structures such as rods, slabs, tubes, and bubbles appear sequentially as density increases. The critical proton fractions $Y_{p}^{drip}$ ( $\approx 0.26$ -0.31) for neutron drip are obtained, where neutron gas emerges outside of nuclei at $Y_{p} < Y_{p}^{drip}$ . For dense stellar matter at small densities ( $n_{b} ≲ 1 0^{- 5} fm^{- 3}$ ) or large proton fractions ( $n_{b} ≲ 0.1 fm^{- 3}$ and $Y_{p} ≳ Y_{p}^{drip}$ ), the EOSs and microscopic structures are generally insensitive to the adopted density functionals. With the onset of neutron drip at $Y_{p} ≲ Y_{p}^{drip}$ , the uncertainties emerge and peak at $n_{b} \approx 0.02 fm^{- 3}$ within the range $1 0^{- 5} ≲ n_{b} ≲ 0.1 fm^{- 3}$ . At $n_{b} ≳ 0.1 fm^{- 3}$ , the dense stellar matter becomes uniform and muons eventually appear, where the uncertainties in the EOSs grow significantly.
↳ astro-ph.HEnucl-thPRC(2026)·5 citations
14
The QUEST Database of Highly-Accurate Excitation Energies
Pierre-François Loos · Martial Boggio-Pasqua · Aymeric Blondel · Filippo Lipparini · Denis Jacquemin
We report theoretical best estimates of vertical transition energies (VTEs) for a large number of excited states and molecules: the \textsc{quest} database. This database includes 1489 \emph{aug}-cc-pVTZ VTEs (731 singlets, 233 doublets, 461 triplets, and 64 quartets) for both valence and Rydberg transitions occurring in molecules containing from 1 to 16 non-hydrogen atoms. \textsc{Quest} also includes a significant list of VTEs for states characterized by a partial or genuine double-excitation character, known to be particularly challenging for many computational methods. The vast majority of the reported values are deemed chemically-accurate, that is, are within $\pm 0.05$ eV of the FCI/\emph{aug}-cc-pVTZ estimate. This allows for a balanced assessment of the performance of popular excited-state methodologies. We report the results of such benchmarks for various single- and multi-reference wavefunction approaches, and provide extensive supporting information allowing testing of other models. All corresponding data associated with the \textsc{quest} database, along with analysis tools, can be found in the associated \textsc{GitHub} repository at the following URL: https://github.com/pfloos/QUESTDB.
↳ physics.chem-phcond-mat.mtrl-scicond-mat.str-elnucl-th+1J.Chem.Theor.Comput.(2025)·4 citations
15
Recent Results on the Tetraneutron
Thomas Faestermann · Roman Gernhäuser
We describe the recent experiments which claimed an observation of a tetra-neutron signal. Production reactions like transfer, knockout, fragmentation or photodisintegration have been used at very different experiments and facilities to form systems just made of neutrons. As a possible explanation of the partly contradicting results we suggest that some observed the bound ground state and some an unbound but still correlated state of the four neutrons at different exitation energy. We also refer to some of the theoretical works.
↳ nucl-exnucl-th3 citations
16
Gapless neutron superfluidity in the crust of the accreting neutron stars KS 1731-260 and MXB 1659-29
Valentin Allard · Nicolas Chamel
The interpretation of the thermal evolution of the transiently accreting neutron stars MXB 1659-29 and KS 1731-260 after an outburst is challenging, both within the traditional deep-crustal heating paradigm and the thermodynamically consistent approach of Gusakov and Chugunov that accounts for neutron diffusion throughout the crust. All these studies assume that the neutron superfluid in the crust is at rest. However, we have recently shown that a finite superflow could exist and could lead to a new gapless superfluid phase if quantized vortices are pinned. We have revisited the cooling of MXB 1659-29 and KS 1731-260 and we have found that gapless superfluidity could naturally explain their late time cooling. We pursue here our investigation by performing new simulations of the thermal relaxation of the crust of MXB 1659-29 and KS 1731-260 within a Markov Chain Monte Carlo method accounting for neutron diffusion and allowing for gapless superfluidity. We have varied the global structure of the neutron star, the composition of the heat-blanketing envelope, and the mass accretion rate. In all cases, observations are best fitted by models with gapless superfluidity. Finally, we make predictions that could be tested by future observations.
↳ astro-ph.HEcond-mat.supr-connucl-thEPJA(2024)·6 citations
17
Temperature Dependence of Heavy Quark Diffusion from (2+1)-flavor Lattice QCD
Dennis Bollweg🇺🇸 · Jorge Luis Dasilva Golán🇺🇸 · Olaf Kaczmarek🇩🇪 · Rasmus Norman Larsen🇩🇪 · Guy D. Moore🇩🇪 · Swagato Mukherjee🇺🇸 · Peter Petreczky🇺🇸 · Hai-Tao Shu🇨🇳 · Simon Stendebach🇩🇪 · Johannes Heinrich Weber🇩🇪
We present a lattice determination of the heavy-quark diffusion coefficient in (2+1)-flavor QCD with almost physical quark masses. The momentum and spatial diffusion coefficients are extracted for a wide temperature range, from $T = 163$ MeV to $10$ GeV. The results are in agreement with previous works from the HotQCD collaboration, and show fast thermalization of the heavy quark inside the QGP. Near the chiral crossover temperature $T_{c} ≃ 150$ MeV, our results are close to the AdS/CFT estimation computed at strong coupling.
↳ hep-lathep-thnucl-thJHEP(2025)·23 citations
18
A Generalized False Vacuum Skyrme model
L. A. Ferreira🇧🇷 · L. R. Livramento🇧🇷
We propose a generalization of the False Vacuum Skyrme model for any simple compact Lie groups $G$ that leads to Hermitian symmetric spaces. The Skyrme field that in the original theory takes its values in $S U (2)$ Lie group, now takes its values in $G$ , while the remaining fields correspond to the entries of a symmetric, positive, and invertible $dim G \times dim G$ -dimensional matrix $h$ . This model is also an extension of the generalized BPS Skyrme model. We prove that the global minima correspond to the $h$ fields being self-dual solutions of the generalized BPS Skyrme model, together with a particular field configuration for the Skyrme field that leads to a spherically symmetric topological charge density. As in the case of the original model, the minimization of the energy leads to the so-called reduced problem, defined in the context of false vacuum decay. This imposes a condition on the Skyrme field, which, if satisfied, makes the total energy of the global minima, as well as the main properties of the model, equivalent to those obtained for the $G = S U (2)$ case. We study this condition and its consequences within the generalized rational map ansatz and show how it can be satisfied for $G = S U (p + q)$ , where $p$ and $q$ are positive integers, with the Hermitian symmetric spaces being $S U (p + q) / S U (p) \otimes S U (q) \otimes U (1)$ . In such a case, the model is completely equivalent to the $G = S U (2)$ False Vacuum Skyrme model, independent of the values of $p$ and $q$ . We also provide a numerical study of the baryon density, RMS radius, and binding energy per nucleon, which deepens the previous analysis conducted for the $S U (2)$ False Vacuum Skyrme model. Additionaly, in the case of $G = S U (3)$ , we have studied the application of our model to the description of the binding energies and masses of the $Λ$ -hypernuclei.
↳ hep-thmath-phmath.MPnlin.SI+1J.Phys.G(2026)·1 citation
19
Exact Renormalization Relation and Binding Energies for Three Identical Bosons
Langxuan Chen · Pengfei Zhang
In the low-energy limit, non-relativistic particles with short-range interactions exhibit universal behavior that is largely independent of microscopic details. This universality is typically described by effective field theory, in which the two-body interaction is renormalized to a single parameter-the scattering length. For systems of identical bosons, the three-body problem reveals the Efimov effect, a novel phenomenon proposed that necessitates the introduction of an additional three-body parameter. However, the exact relation between this three-body parameter, the coupling constants in the effective field theory, and the binding energies of Efimov states remains unresolved. In this Letter, we address this question through a comprehensive analysis of the Skorniakov-Ter-Martirosian equation with a finite cutoff. We establish an exact renormalization relation for the three-body parameter and determine its connection to the energies of Efimov bound states. These results are validated through high-precision numerical simulations. We expect our findings to be of fundamental interest across various fields, including atomic, nuclear, condensed matter, and particle physics, and to have broad applications in both few-body and many-body physics.
↳ cond-mat.quant-gasnucl-thPRA(2025)·3 citations
20
Studying Maximal Entanglement and Bell Nonlocality at an Electron-Ion Collider
Wei Qi🇨🇳 · Zijing Guo🇨🇳 · Bo-Wen Xiao🇨🇳
In this paper, we propose to test quantum entanglement and Bell nonlocality at an Electron-Ion Collider (EIC). By computing the spin correlations in quark-antiquark pairs produced via photon-gluon fusion, we find that longitudinally polarized photons produce maximal entanglement at leading order, while transversely polarized photons generate significant entanglement near the threshold and in the ultra-relativistic regime. Compared to hadron colliders, the EIC provides a cleaner experimental environment for measuring entanglement through the $γ^{*} g \to q q ˉ$ channel, offering a strong signal and a promising avenue to verify Bell nonlocality. This study extends entanglement measurements to the EIC, presenting new opportunities to explore the interplay of quantum information phenomena and hadronic physics in the EIC era.
↳ hep-phhep-exnucl-exnucl-th+1PRD(2026)·32 citations
21
Connecting dilaton thermal fluctuation with the Polyakov loop at finite temperature
Bing-Kai Sheng🇨🇳 · Yong-Liang Ma🇨🇳
Understanding the character of the deconfinement phase transition is one of the fundamental challenges in particle physics. In this work, we derive a formula for the expectation value of the Polyakov loop -- the order parameter of the deconfinement phase transition -- in pure $SU (N_{c})$ gauge systems at finite temperatures starting from the Coleman\textendash Weinberg-type effective potential encoding the trace anomaly of QCD. Our results are in good agreement with the Lattice QCD data and can effectively describe the large- $N_{c}$ behaviors of the expectation value of the Polyakov loop. Notably, our findings predict the strongest first-order deconfinement phase transition as $N_{c} \to + \infty$ . Furthermore, to establish a relation between the dilaton field and the Polyakov loop, we also derive the scale transformation rule for temperature based on quantum statistical mechanics. The results of this work may shed a light on the connection between deconfinement phase transition and evolution of scale symmetry in the thermal system.
↳ hep-phhep-latnucl-thJHEP(2026)·2 citations
22
Joint analysis of reactor and accelerator CE $ν$ NS data on germanium: implications for the Standard Model and nuclear physics
M. Atzori Corona🇮🇹 · M. Cadeddu🇮🇹 · N. Cargioli🇮🇹 · G. Co'🇮🇹 · F. Dordei🇮🇹 · C. Giunti🇮🇹
This work presents the first comprehensive joint analysis of all available Coherent Elastic Neutrino-Nucleus Scattering (CE $ν$ NS) data on germanium: those observed at the Spallation Neutron Source (SNS) by the COHERENT collaboration and those of the nuclear reactors revealed by the CONUS+ experiment using germanium detectors. In addition to COHERENT and CONUS+, we incorporate reactor data from TEXONO and $ν$ GeN, thereby enhancing both the statistical significance and the systematic reliability of our study. We provide state-of-the-art determinations of key nuclear physics and Standard Model parameters, including the neutron root-mean-square (rms) radius of germanium nuclei, the weak mixing angle, and the neutrino charge radius. The observed tension of about $2 σ$ between the COHERENT germanium measurement and the Standard Model prediction motivates a detailed reassessment of the theoretical cross-section. In particular, we examine the impact of nuclear form factors and uncertainties in the nuclear radius, as well as the potential influence of a systematic shift in the neutrino flux normalisation at the SNS. Our results highlight the reliability of CE $ν$ NS as a precision tool, reinforced by the complementarity of different experimental inputs, and lay the groundwork for future advances in the field.
↳ hep-phhep-exnucl-thPLB(2025)·13 citations
23
Global QCD analysis of spin PDFs in the proton with high- $x$ and lattice constraints
C. Cocuzza🇺🇸 · N. T. Hunt-Smith🇦🇺 · W. Melnitchouk🇺🇸 · N. Sato🇺🇸 · A. W. Thomas🇦🇺
We perform a comprehensive global QCD analysis of spin-dependent parton distribution functions (PDFs), combining all available data on inclusive and semi-inclusive deep-inelastic scattering (DIS), as well as inclusive weak boson and jet production in polarized $pp$ collisions, simultaneously extracting spin-averaged PDFs and fragmentation functions. Including recent Jefferson Lab DIS data at high $x$ , together with subleading power corrections to the leading twist framework, allows us to verify the stability of the PDFs for $W^{2} \geq 4$ GeV $^{2}$ and quantify the uncertainties on the spin structure functions more reliably. We explore the use of new lattice QCD data on gluonic pseudo Ioffe-time distributions, which, together with jet production and high- $x$ DIS data, improve the constraints on the polarized gluon PDF. The expanded kinematic reach afforded by the data into the high- $x$ region allows us to refine the bounds on higher twist contributions to the spin structure functions, and test the validity of the Bjorken sum rule.
↳ hep-phhep-latnucl-thPRD(2025)·22 citations
24
Bayesian Quantification of Observability and Equation of State of Twin Stars
Xavier Grundler🇺🇸 · Bao-An Li🇺🇸
The possibility of discovering twin stars, two neutron stars (NSs) with the same mass but different radii, is usually studied in forward modelings by using a restricted number of NS matter equation of state (EOS) encapsulating a first-order phase transition from hadronic to quark matter (QM). Informing our likelihood function with the NS radius data from GW170817 and using a meta-model with 9-parameters capable of mimicking most NS EOSs available in the literature, we conduct a Bayesian quantification of the observability and underlying EOSs of twin stars. Of the accepted EOSs, between 12-18\% yield twin stars, depending on the restrictions we place on the second branch. The possibility of twin stars remains robust even under recent observational constraints. We show that many of these twin star scenarios are observable with currently available levels of accuracy in measuring NS radii. We also present the marginalized posterior probability density functions (PDFs) of every EOS parameter for each of four mass-radius correlation topologies. We find that the inferred EOS depends sensitively on not only whether twin stars are present, but also the category of twin stars, indicating that the observation of twin stars would provide a strong constraint on the underlying EOS. In particular, for two coexisting hybrid stars having QM cores at different densities, the PDF for QM speed of sound squared $c_{qm}^{2}$ has two peaks, one below and another above the conformal limit $c_{qm}^{2} = 1/3$ predicted by perturbative QCD.
↳ astro-ph.HEastro-ph.GAastro-ph.SRnucl-ex+1PRD(2025)·18 citations

Affiliations

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