Nuclear Theory·nucl-th

Thursday·November 21, 2024

15 papers—7 primary·8 cross-listed

08
[Submitted on 19 Nov 2024] (cross-list from hep-lat)
Entanglement entropy of a color flux tube in (1+1)D Yang-Mills theory
Rocco Amorosso🇺🇸 · Sergey Syritsyn🇺🇸 · Raju Venugopalan🇺🇸
In recent work arxiv:2410.00112 , we computed a novel flux tube entanglement entropy (FTE $^{2}$ ) of the color flux tube stretched between a heavy quark-antiquark pair on a Euclidean lattice in (2+1)D Yang-Mills theory. Our numerical results suggested that FTE $^{2}$ can be partitioned into an internal color entanglement entropy and a vibrational entropy corresponding to the transverse excitations of a QCD string, with the latter described by a thin string model. Since the color flux tube does not have transverse excitations in (1+1)D, we analytically compute the contribution of the internal color degrees of freedom to FTE $^{2}$ in this simpler framework. For the multipartite partitioning of the color flux tube, we find the remarkable result that FTE $^{2}$ only depends on the number of times the flux tube crosses the border between two spatial regions, and the dimension of the representation of the color group, but not on the string length. The result holds independently of whether the branching points are placed on the vertices of the lattice or in the center of plaquettes.
Comments:
14 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:
2411.12818 [pdf]
PLB(2025)·19 citations
09
[Submitted on 19 Nov 2024] (cross-list from hep-ph)
Equation of state of isospin asymmetric QCD with small baryon chemical potentials
Bastian B. Brandt🇩🇪 · Gergely Endrodi🇩🇪 · G. Markó🇭🇺
We extend our measurement of the equation of state of isospin asymmetric QCD to small baryon and strangeness chemical potentials, using the leading order Taylor expansion coefficients computed directly at non-zero isospin chemical potentials. Extrapolating the fully connected contributions to vanishing pion sources is particularly challenging, which we overcome by using information from isospin chemical potential derivatives evaluated numerically. Using the Taylor coefficients, we present, amongst others, first results for the equation of state along the electric charge chemical potential axis, which is potentially of relevance for the evolution of the early Universe at large lepton flavour asymmetries.
Comments:
10 pages, 10 figures, contribution to the 41st International Symposium on Lattice Field Theory (LATTICE2024), Liverpool, UK; v2: typos and the extraction of the equation of state at non-zero charge chemical potential corrected, conclusions unchanged
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2411.12918 [pdf]
PoS(2025)·10 citations
10
[Submitted on 19 Nov 2024] (cross-list from astro-ph.HE)
Non-Newtonian corrections to radiative viscosity: Israel-Stewart theory as a viscosity limiter
Lorenzo Gavassino
Radiation is a universal friction-increasing agent. When two fluid layers are in relative motion, the inevitable exchange of radiation between such layers gives rise to an effective force, which tries to prevent the layers from sliding. This friction is often modeled as a Navier-Stokes shear viscosity. However, non-Newtonian corrections are expected to appear at distances of about one optical depth from the layers' interface. Such corrections prevent the viscous stress from becoming too large. Here, we set the foundations of a rigorous theory for these corrections, valid along incompressible flows. We show that, in the linear regime, the infinite Chapman-Enskog series can be computed analytically, leading to universal formulas for all transport coefficients, which apply to any fluid, with any composition, with radiation of any type (also neutrinos), and with nearly any type of radiative process. We then show that, with an appropriate shear-heat coupling coefficient, Israel-Stewart theory can correctly describe most non-Newtonian features of radiative shear stresses.
Comments:
8 pages (main text) + 11 pages (supplementary material), published on PRD (see https://journals.aps.org/prd/abstract/10.1103/PhysRevD.111.L081306)
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2411.12929 [pdf]
PRD(2025)·2 citations
11
[Submitted on 20 Nov 2024] (cross-list from physics.chem-ph)
Anomalous propagators and the particle-particle channel: Bethe-Salpeter equation
Antoine Marie🇫🇷 · Pina Romaniello🇫🇷 · Xavier Blase🇫🇷 · Pierre-François Loos🇫🇷
The Bethe-Salpeter equation has been extensively employed to compute the two-body electron-hole propagator and its poles which correspond to the neutral excitation energies of the system. Through a different time-ordering, the two-body Green's function can also describe the propagation of two electrons or two holes. The corresponding poles are the double ionization potentials and double electron affinities of the system. In this work, a Bethe-Salpeter equation for the two-body particle-particle propagator is derived within the linear-response formalism using a pairing field and anomalous propagators. This framework allows us to compute kernels corresponding to different self-energy approximations ( $G W$ , $T$ -matrix, and second-Born) as in the usual electron-hole case. The performance of these various kernels is gauged for singlet and triplet valence double ionization potentials using a set of 23 small molecules. The description of double core hole states is also analyzed.
Comments:
19 pages, 8 figures
Subjects:
physics.chem-ph (physics.chem-ph); cond-mat.mtrl-sci (cond-mat.mtrl-sci); Mathematical Physics (math-ph); math.MP (math.MP); Nuclear Theory (nucl-th)
arXiv:
2411.13167 [pdf]
J.Chem.Phys.(2025)·4 citations
12
[Submitted on 20 Nov 2024] (cross-list from hep-ph)
Two-pion exchange for coupled-channel scattering of two heavy mesons
J.T. Chacko🇩🇪 · V. Baru🇩🇪 · C. Hanhart🇩🇪 · S.L. Krug🇩🇪
To improve the theoretical understanding of multiquark states like $Z_{b} (10610)$ and $Z_{b} (10650)$ , we calculate the heavy-meson heavy-(anti)meson scattering potential up to next-to-leading order, $O (Q^{2})$ , within chiral effective field theory ( $χ$ EFT) employing a power counting scheme that explicitly keeps track with the large momentum scale $Q \sim 2 μ δ$ (where $δ = m_{V} - m_{P}$ is the vector-pseudoscalar mass difference and $μ$ their reduced mass) introduced by the coupled channel dynamics. We provide expressions for the two-pion exchange (TPE) terms up to $O (Q^{2})$ and their partial-wave decomposition. We show that these potentials are well-approximated by contact terms at $O (Q^{2})$ , with minor residual non-analytic TPE contributions, supporting $χ$ EFT convergence in the theoretical predictions for $Z_{b} (10610)$ and $Z_{b} (10650)$ , as well as their spin partners. These findings are also relevant for $D^{(*)} D^{(*)}$ scattering, especially for the $T_{cc}$ state, for both physical and lattice QCD data with moderately larger pion masses. We further demonstrate that the differences between isovector and isoscalar potentials for heavy mesons are naturally explained by the TPE contributions.
Comments:
41 pages, 18 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2411.13303 [pdf]
PRD(2025)·11 citations
13
[Submitted on 20 Nov 2024] (cross-list from hep-ph)
Dispersive Determination of Nucleon Gravitational Form Factors
Xiong-Hui Cao🇨🇳 · Feng-Kun Guo🇨🇳 · Qu-Zhi Li🇨🇳 · De-Liang Yao🇨🇳
Being closely connected to the origin of the nucleon mass, the gravitational form factors of the nucleon have attracted significant attention in recent years. We present the first model-independent determinations of the gravitational form factors of the pion and nucleon at the physical pion mass, using a data-driven dispersive approach. The so-called "last global unknown property" of the nucleon, the $D$ -term, is determined to be $- 3.3 8_{- 0.35}^{+ 0.34}$ . The root mean square radius of the scalar trace density inside the nucleon is determined to be $(0.97 \pm 0.03) fm$ . Notably, this value is larger than the proton charge radius, suggesting a modern structural view of the nucleon where gluons, responsible for most of the nucleon mass, are distributed over a larger spatial region than quarks, which dominate the charge distribution, indicating that the radius of the trace density may be regarded as a confinement radius. We also predict the nucleon angular momentum and mechanical radii, providing further insights into the intricate internal structure of the nucleon.
Comments:
v2: 10 pages, 6 figures, 1 table. Adopted a more conservative error analysis: minor shifts in results (central values unchanged). Expanded supplementary material: added derivations of GFF unitarity relations and input discussions. Clarifications of mass radius added, title changed, main conclusions unchanged
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2411.13398 [pdf]
Nature Commun.(2025)·57 citations
14
[Submitted on 20 Nov 2024] (cross-list from hep-ph)
Global analysis of $μ \to e$ interactions in the SMEFT
Filippo Delzanno🇺🇸 · Kaori Fuyuto🇺🇸 · Sergi Gonzàlez-Solís🇺🇸 · Emanuele Mereghetti🇺🇸
We study current experimental bounds on charged lepton flavor violating (CLFV) $μ$ - $e$ interactions in the model-independent framework of the Standard Model Effective Field Theory (SMEFT). Assuming a generic flavor structure in the quark sector, we consider the contributions of CLFV operators to low-energy observables, including $μ \to e γ$ and $μ \to e$ conversion for quark-flavor conserving operators and CLFV meson decays for quark-flavor violating operators. At high energy, we consider limits on CLFV decays of the Higgs and Z bosons and of the top quark, and obtain bounds on operators with light quarks by recasting searches for production of $e μ$ pairs in $pp$ collisions at the Large Hadron Collider (LHC). We connect observables at low- and high-energy by taking into account renormalization group running and matching between CLFV operators. We also discuss the sensitivity of the future Electron-Ion Collider, where the prospective bounds are derived by imposing simple cuts on final state particles. We find that, in a single operator scenario, bounds on purely leptonic operators are dominated by $μ \to e γ$ and $μ \to e$ conversion. Semileptonic operators with down-type quarks are also dominantly constrained by low-energy observables, while LHC searches lead the bounds on up-type quark-flavor violating operators. Taking simplified multiple-coupling scenarios, we show that it is easy to evade the strongest low-energy bounds from spin-independent $μ \to e$ conversion, and that collider searches are competitive and complementary to constraints from spin-dependent $μ \to e$ conversion and other low-energy probes.
Comments:
52 pages, 10 figures. Version published in JHEP
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2411.13497 [pdf]
JHEP(2025)·13 citations
15
[Submitted on 20 Nov 2024] (cross-list from hep-ph)
Finite-size effects on small- $x$ evolution and saturation in proton and nuclear targets
Heikki Mäntysaari🇫🇮 · Jani Penttala🇺🇸 · Farid Salazar🇺🇸 · Björn Schenke🇺🇸
Within the Color Glass Condensate effective field theory, we assess the importance of including a finite size for the target on observables sensitive to small- $x$ evolution. To this end, we study the Balitsky-Kovchegov (BK) equation with impact-parameter dependence in the initial condition. We demonstrate that neglecting the dependence on the impact parameter can result in overestimated saturation effects for protons, while it has little effect for heavy nuclei at the energies available at current experiments. When fixing the nonperturbative parameters to the energy dependence of the exclusive $J / ψ$ photoproduction cross section with proton targets, predictions for lead targets are not sensitive to the applied running-coupling prescription, the scheme chosen to resum large transverse logarithms in the BK equation, or the infrared regulator in the evolution.
Comments:
16 pages, 19 figures; v2: updated Fig. 8, matches published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2411.13533 [pdf]
PRD(2025)·29 citations

Affiliations

first authorsco-authorsvia INSPIRE