Nuclear Theory·nucl-th

Tuesday·April 15, 2025

23 papers—12 primary·11 cross-listed

13
[Submitted on 11 Apr 2025] (cross-list from hep-th)
Universality of $S U (\infty)$ relaxation dynamics for $S U (n_{f})$ -symmetric spin-models
Duff Neill🇺🇸 · Hanqing Liu🇺🇸
Spin-models, where the $N$ spins interact pairwise with a $S U (n_{f})$ symmetry preserving hamiltonian, famously simplify in the large $n_{f}$ , $N$ limits, as derived by Sachdev and Ye when exploring mean-field behavior of spin-glasses. We present numerical evidence that for a large class of models, the large $n_{f}$ limit is not necessary: the same dynamical equations can describe the relaxation processes at high temperatures for a set of classical models inspired from mean-field treatments of interacting dense neutrino gases, up to times set by the radius of convergence of the perturbation series for the correlation function. After a simple rescaling of time, the dynamics display a surprising universality, being identical for any value of $n_{f}$ as long as the rank of the coupling matrix is small. As a corollary of our results, we find that the direct interaction approximation originating from the study of stochastic flows in fluid turbulence should be thought of as only a short-time approximation for generic random coupling systems.
Comments:
LA-UR-25-20460
Subjects:
High Energy Physics — Theory (hep-th); cond-mat.dis-nn (cond-mat.dis-nn); Nuclear Theory (nucl-th); Fluid Dynamics (physics.flu-dyn)
arXiv:
2504.08925 [pdf]
1 citation
14
[Submitted on 12 Apr 2025] (cross-list from hep-ph)
Femtoscopy for exotic hadrons and nuclei
Tetsuo Hyodo
In high energy collision experiments with multiple hadron productions, the momentum distribution of the measured hadron pair shows a correlation due to the final state hadron interactions and the quantum statistics. In the past, this femtoscopy technique has been developed to extract the information of the emission source from the momentum correlation functions. Recently, correlation function measurement is utilized also as a new method to determine the hadron interactions. In fact, the ALICE collaboration at LHC measures the correlation functions with various hadron pairs, for which the standard scattering experiment is difficult, providing remarkable progress in the study of the hadron interactions. In this contribution, we introduce the theoretical method to calculate the correlation functions, and present recent results on the study of the antikaon-nucleon interactions and hyperon-nucleus interactions.
Comments:
11 pages, 3 figures, Talk given at The XVIth Quark Confinement and the Hadron Spectrum Conference (QCHSC24), 19-24 August, 2024
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2504.09017 [pdf]
PoS(2025)·2 citations
15
[Submitted on 12 Apr 2025] (cross-list from nucl-ex)
Event-shape dependence of symmetry plane correlations using the Gaussian estimator in Pb-Pb collisions at the LHC using a multiphase transport model
Sarthak Tripathy🇮🇳 · Suraj Prasad🇮🇳 · Raghunath Sahoo🇮🇳
The study of symmetry plane correlations (SPCs) can be useful in characterizing the direction of the anisotropic emission of produced particles in the final state. The study of SPCs provides an independent method to understand the transport properties of the system formed in heavy-ion collisions. Similar to anisotropic flow coefficients, which are largely influenced by the initial spatial anisotropy, SPCs also depend upon the participant plane correlations measured using the participating nucleons of the collision overlap region. In this paper, SPCs have been studied in Pb-Pb collisions at $s_{NN} = 5.02$ TeV using the event generator AMPT. In addition to their behaviour with the changing centrality of the collision, their event shape dependence has also been studied for the first time, using the event shape classifier transverse spherocity. The Gaussian estimator has been used to evaluate the correlations, and these have been compared to the participant plane correlations defined in an analogous way to the symmetry plane correlations, and a qualitative match has been found between them. These event-shape differentiated symmetry plane correlations can be used to deduce the presence of higher-order anisotropies in the initial energy distribution, thus giving insight into the initial geometry of the colliding system, among other applications like model development and model testing using Bayesian analyses.
Comments:
Same as the published version in Phys. Rev. D
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2504.09275 [pdf]
PRD(2025)·7 citations
16
[Submitted on 12 Apr 2025] (cross-list from hep-ph)
Discovery of High-momentum Nucleon Correlations in Nuclei -- an Early History
Leonid Frankfurt🇮🇱 · Mark Strikman🇺🇸
We summarize the reasons for using the light-cone mechanics of nuclei for description of high-energy nuclear processes and describe the steps, which have led to the discovery of high-momentum correlations in nuclei.
Comments:
Submitted to Acta Physica Polonica B special volume dedicated to Dmitry Diakonov, Victor Petrov and Maxim Polyakov
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2504.09337 [pdf]
Acta Phys.Polon.B(2025)·0 citations
17
[Submitted on 12 Apr 2025] (cross-list from hep-ph)
Extracting Meson Distribution Amplitudes from Nonlocal Euclidean Correlations at Next-to-Next-to-Leading Order
Yao Ji🇨🇳 · Fei Yao🇨🇳 · Jian-Hui Zhang🇨🇳
We present the first complete result for the next-to-next-to-leading order (NNLO) hard matching kernel indispensable for a precision extraction of light meson distribution amplitudes from lattice calculations of equal-time nonlocal Euclidean correlation functions. The results are given in both coordinate and momentum space, with the renormalization and matching accomplished in a state-of-the-art scheme. Our results can be used in both large-momentum effective theory and short-distance factorization approaches. Notably, our coordinate space kernel is directly applicable to nonsinglet quark unpolarized and helicity generalized parton distributions as well. We also illustrate the numerical impact of the NNLO matching, using the pion distribution amplitude as an example.
Comments:
11 pages, 4 figures. Supplementary Mathematica notebook (Matching_coefficient.nb) is included
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2504.09367 [pdf]
7 citations
18
[Submitted on 13 Apr 2025] (cross-list from hep-ph)
Prompt and non-prompt production of charm hadrons in proton-proton collisions at the Large Hadron Collider using machine learning
Raghunath Sahoo🇮🇳 · Suraj Prasad🇮🇳 · Neelkamal Mallick🇮🇳 · Kangkan Goswami🇮🇳 · Gagan B. Mohanty🇮🇳
In this contribution, we use machine learning (ML) based models to separate the prompt and non-prompt production of heavy flavour hadrons, such as $D^{0}$ and J/ $ψ$ , in proton-proton collisions at LHC energies. For this purpose, we use PYTHIA~8 to generate events, which provides a good qualitative agreement with experimental measurements of charm hadron production. The input features for the ML models are experimentally measurable. The prediction accuracy of the ML models used in this study reaches up to 99\%. The ML models can be useful in providing precise track-level identification, which is not possible in experiments with traditional methods. The contribution also discusses future applications of the ML models to understand the production of prompt and non-prompt heavy quark hadrons.
Comments:
5 pages, 3 captioned figures. A part of the ATHIC 2025 conference proceedings. Presented by Raghunath Sahoo
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2504.09541 [pdf]
J.Subatomic Part.Cosmol.(2025)·0 citations
19
[Submitted on 13 Apr 2025] (cross-list from hep-ph)
Deciphering the viscous properties and the Bjorken expansion of the QGP medium at finite angular velocity
Shubhalaxmi Rath🇮🇷 · Nicolás A. Neill🇨🇱
We have studied the viscous properties as well as the Bjorken expansion of a rotating QGP medium. In the noncentral events of heavy-ion collisions, the produced medium can carry a finite angular momentum with a finite range of angular velocity. This rotation can significantly affect various properties, including viscous properties and the expansion of the QGP medium. Using a novel relaxation time approximation for the collision integral in the relativistic Boltzmann transport equation at finite angular velocity, we have calculated the shear and bulk viscosities and compared them with their counterparts in the standard relaxation time approximation within the kinetic theory approach. Our results show that the angular velocity increases both shear and bulk viscosities, suggesting an enhanced momentum transfer within the medium and greater fluctuations in local pressure. This rotational effect on viscosities is more evident at lower temperatures than at higher temperatures. Our analysis also shows that, compared to the standard relaxation time approximation, the shear viscosity is lower while the bulk viscosity is higher in the novel relaxation time approximation for all temperatures. Additionally, some observables related to the flow characteristic, fluid behavior and conformal symmetry of the medium are markedly impacted due to rotation. We have also studied the hydrodynamic evolution of matter within the Bjorken boost-invariant scenario and have found that the energy density evolves faster in the presence of finite rotation than in the nonrotating case. Consequently, rapid rotation accelerates the cooling process of the QGP medium.
Comments:
33 pages, 10 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2504.09668 [pdf]
PRD(2025)·1 citation
20
[Submitted on 14 Apr 2025] (cross-list from hep-ph)
Understanding baryon stopping at the BNL Relativistic Heavy Ion Collider top energies
Niseem Magdy🇺🇸 · Prithwish Tribedy🇺🇸 · Chun Yuen Tsang🇺🇸 · Zhangbu Xu🇺🇸
The nucleon exhibits a rich internal structure governed by Quantum Chromodynamics (QCD), where its electric charge arises from valence quarks, while its spin and mass emerge from complex interactions among valence quarks, sea (anti-)quarks, and gluons. At the advent of QCD, an alternative hypothesis emerged suggesting, at high energies, the transport of a nucleon's baryon number could be traced by a non-perturbative configuration of gluon fields connecting its three valence quarks, forming a $Y$ -shaped topology known as the gluon junction. Recent measurements by the STAR experiment are compatible with this scenario. In light of these measurements, this study aims to explore the mechanisms of baryon transport in high-energy nuclear collisions using the PYTHIA-8 framework, which incorporates a state-of-the-art hadronization model with advanced Color Flow (CF) and Color Reconnection (CR) mechanisms that mimic signatures of a baryon junction. Within this model setup, we investigate (i) the rapidity slope of the net-baryon distributions in photon-included processes ( $γ$ +p) and (ii) baryon over charge transport in the isobaric (Ru+Ru and Zr+Zr) collisions. Our study highlights the importance of the CF and CR mechanisms in PYTHIA-8, which play a crucial role in baryon transport. The results show that the CF and CR schemes significantly affect the isobaric baryon-to-charge ratio, leading to different predictions for baryon stopping and underscoring the need to account for CF and CR effects in comparisons with experimental measurements.
Comments:
8 pages, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2504.09826 [pdf]
PRC(2025)·4 citations
21
[Submitted on 14 Apr 2025] (cross-list from hep-ph)
Revisiting the deuteron mass radius via near-threshold $ρ^{0}$ , $ω$ and $ϕ$ meson photoproduction
Xiaoxuan Lin🇨🇳 · Wei Kou🇨🇳 · Shixin Fu🇨🇳 · Rong Wang🇨🇳 · Chengdong Han🇨🇳 · Xurong Chen🇨🇳
We present a comprehensive analysis of near-threshold photoproduction of $ρ^{0}$ , $ω$ , and $ϕ$ mesons on a deuterium target, utilizing published datasets from DESY and SLAC for $ρ^{0}$ and $ω$ production, as well as data from the LEPS and CLAS Collaborations for $ϕ$ production. In extracting the deuteron mass radius, we adopt a dipole parametrization for the scalar gravitational form factor, which effectively captures the $∣ t ∣$ -dependence of the differential cross sections associated with vector meson photoproduction. In addition, results from alternative commonly used form factor parametrizations are also considered and compared. Employing the vector meson dominance (VMD) framework and invoking low-energy Quantum Chromodynamics (QCD) theorems, we extract the deuteron mass radius from near-threshold photoproduction data of $ρ^{0}$ , $ω$ , and $ϕ$ mesons. The mass radii obtained from the various datasets are found to be consistent within statistical uncertainties, yielding an average value of $2.03 \pm 0.13$ fm under the dipole form assumption. We also provide a detailed discussion of the sensitivity of the extracted radius to different choices of gravitational form factor models. Our result represents a significant improvement in precision compared to earlier estimates based solely on $ϕ$ meson photoproduction, offering new constraints for theoretical models of nuclear structure and deepening our understanding of the mass distribution within the deuteron.
Comments:
9 pages, 5 figures, 5 tables. Accepted by Chinese physics C
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2504.10023 [pdf]
CPC(2025)·1 citation
22
[Submitted on 14 Apr 2025] (cross-list from hep-ph)
Automated next-to-leading order QCD and electroweak predictions of photon-photon processes in ultraperipheral collisions
Hua-Sheng Shao🇫🇷 · Lukas Simon🇫🇷
We present automated next-to-leading order QCD and/or electroweak (EW) predictions for photon-photon processes in ultraperipheral high-energy collisions of protons and ions, extending the capabilities of the MadGraph5_aMC@NLO framework together in combination with the gamma-UPC code. Key aspects of this extension are discussed. We compute QCD and/or EW quantum corrections for several phenomenologically interesting processes at LHC and FCC-hh energies.
Comments:
35 pages, 4 figures, 11 tables; v2: journal version (minor corrections wrt v1)
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2504.10104 [pdf]
JHEP(2025)·9 citations
23
[Submitted on 14 Apr 2025] (cross-list from hep-ph)
Probing the Sivers Asymmetry with Transverse Energy-Energy Correlators in the Small- $x$ Regime
Shohini Bhattacharya🇺🇸 · Zhong-Bo Kang🇺🇸 · Diego Padilla🇺🇸 · Jani Penttala🇺🇸
We investigate transverse energy-energy correlators (TEECs) for both polarized and unpolarized targets in the small- $x$ regime at the Electron-Ion Collider (EIC). Focusing on the approximately back-to-back electroproduction of a hadron-electron pair, we apply transverse-momentum-dependent (TMD) factorization formulas that incorporate TMD evolution for both event-shape observables and expand them in terms of the small- $x$ dipole amplitude. This allows us to write the TEEC off the transversely polarized proton in terms of a C-odd interaction, corresponding to an odderon exchange. Due to the charge-conjugation-odd nature of the small- $x$ quark Sivers function, we restrict the sum over final hadronic states to positively and negatively charged hadrons separately. We present numerical predictions for the TEEC Sivers asymmetry at the EIC and find the magnitude of the asymmetry to be on the $0.01%$ level. This channel offers a promising avenue for benchmarking the still largely unconstrained odderon amplitude.
Comments:
19 pages, 5 figures; v2: corrected angular variable to xi, corrected Eq. (2.27), updated results
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2504.10475 [pdf]
17 citations

Affiliations

first authorsco-authorsvia INSPIRE