Nuclear Theory·nucl-th

Thursday·August 22, 2024

8 papers—3 primary·5 cross-listed

04
[Submitted on 21 Aug 2024] (cross-list from hep-ph)
Towards a first principles light-front Hamiltonian for the nucleon
Siqi Xu🇨🇳 · Yiping Liu🇨🇳 · Chandan Mondal🇨🇳 · Jiangshan Lan🇨🇳 · Xingbo Zhao🇨🇳 · Yang Li🇨🇳 · James P. Vary🇺🇸
We solve the nucleon's wave functions from the eigenstates of the light-front quantum chromodynamics Hamiltonian for the first time, using a fully relativistic and nonperturbative approach based on light-front quantization, without an explicit confining potential. These eigenstates are determined for the three-quark, three-quark-gluon, and three-quark-quark-antiquark Fock representations, making them suitable for low-resolution probes. From this, we calculate the nucleon's quark and gluon matter densities, helicity, and transversity distributions, which show qualitative consistency with experimental extractions. We also compute the contributions of quark and gluon helicity to the proton spin and the tensor charges. The obtained light-front wave functions represent a significant advancement towards a unified description of various hadron distribution functions in both longitudinal and transverse momentum space.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2408.11298 [pdf]
PLB(2025)·24 citations
05
[Submitted on 21 Aug 2024] (cross-list from hep-ph)
Photoproduction $γ p \to f_{0} (980) p$ in an effective Lagrangian approach
Neng-Chang Wei🇨🇳 · Ai-Chao Wang🇨🇳 · Fei Huang🇨🇳
The most recent data on differential cross sections and photon beam asymmetries $Σ$ from the LEPS2/BGOegg Collaboration for the $γ p \to f_{0} (980) p$ reaction are analyzed within a tree-level effective Lagrangian approach. The $t$ -channel $ρ$ and $ω$ exchanges, the $u$ - and $s$ -channel $N$ exchanges, the interaction current, and the possible $s$ -channel $N^{*}$ exchanges are taken into account in constructing the reaction amplitudes to reproduce the data. The results show that the contributions from either the $N (2040) 3/ 2^{+}$ or the $N (2100) 1/ 2^{+}$ resonance exchange in the $s$ channel are necessarily required to describe the LEPS2/BGOegg data and they dominate the differential cross sections of $γ p \to f_{0} (980) p$ . Further analysis shows that the contributions from the $t$ -channel $ρ$ and $ω$ exchanges and the interaction current are rather small to both differential cross sections and photo beam asymmetries, and the contributions from $u$ -channel $N$ exchange are considerable in the case of including $N (2040) 3/ 2^{+}$ in the model while negligible in the case of including $N (2100) 1/ 2^{+}$ in the model. Predictions of target asymmetries $T$ for $γ p \to f_{0} (980) p$ are given, which can be examined by future experiments.
Comments:
8 pages,8 figures, to be published in Physical Review C
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2408.11352 [pdf]
PRC(2024)·4 citations
06
[Submitted on 21 Aug 2024] (cross-list from hep-th)
Second-order spin hydrodynamics from Zubarev's nonequilibrium statistical operator formalism
Abhishek Tiwari🇮🇳 · Binoy Krishna Patra🇮🇳
Using the Zubarev's nonequilibrium statistical operator formalism, we derive the second-order expression for the dissipative tensors in relativistic spin hydrodynamics, {\em viz.} rotational stress tensor ( $τ_{μν}$ ), boost heat vector ( $q_{μ}$ ), shear stress tensor ( $π_{μν}$ ), and bulk viscous pressure ( $Π$ ). The first two ( $τ_{μν}$ and $q_{μ}$ ) emerge due to the inclusion of the antisymmetric part in the energy-momentum tensor, which, in turn, governs the conservation of spin angular momentum ( $Σ^{α μν}$ ). As a result, new thermodynamic forces, generated due to the antisymmetric part of $T_{μν}$ , contain the spin chemical potential. In this work, we have also taken the spin density ( $S^{μν}$ ) as an independent thermodynamic variable, in addition to the energy density and particle density, thereby resulting in two novel transport coefficients given by the correlation between spin density tensor and rotational stress tensor and vice versa. Additionally, the newly found terms in $π_{μν}$ and $Π$ are the artifacts of the new thermodynamic forces that arise due to the antisymmetric part of $T^{μν}$ . Finally, we have derived the evolution equations for the aforesaid tensors: $τ_{μν}$ , $q_{μ}$ , $π_{μν}$ , and $Π$ .
Comments:
31 pages
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2408.11514 [pdf]
PRD(2025)·19 citations
07
[Submitted on 21 Aug 2024] (cross-list from hep-ph)
Strong decays of $P -$ wave doubly charmed and bottom baryons
Ya-Li Shu🇨🇳 · Qing-Fu Song🇨🇳 · Qi-Fang Lü🇨🇳
In this work, we investigate the strong decays for $P -$ wave excited states of doubly charmed and bottom baryons in the constituent quark model. Our results indicate that some $λ -$ mode $Ξ_{cc / bb} (1 P)$ and $Ω_{cc / bb} (1 P)$ states are relatively narrow, which are very likely to be discovered by future experiments. The light meson emissions for the low-lying $ρ -$ mode states are highly suppressed due to the orthogonality of wave functions between initial and final states. Moreover, the strong decay behaviors for doubly charmed and bottom baryons preserve the heavy superflavor symmetry well, where the small violation originates from the finite heavy quark masses and different phase spaces. We hope that present theoretical results for undiscovered doubly charmed and bottom baryons can provide helpful information for future experiments and help us to better understand the heavy quark symmetry.
Comments:
8 pages, 2 figures, comments and suggestions are welcome
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2408.11578 [pdf]
Commun.Theor.Phys.(2026)·3 citations
08
[Submitted on 21 Aug 2024] (cross-list from hep-ph)
How the QCD trace anomaly behaves at the core of twin stars?
José C. Jiménez🇧🇷 · Lucas Lazzari🇧🇷 · Victor P. Gonçalves🇧🇷
We investigate the behavior of the dense and cold (normalized) QCD trace anomaly, $Δ$ , in the interior of twin neutron stars (obtained from several sets of equations of state in agreement with modern compact-star and multimessenger data) satisfying static and dynamic stability conditions. We scan the formed twin-star parameter space in order to look for effects caused by the presence of a strong first-order phase transition connecting hadron and quark phases by means of a Maxwell construction. We found robustly that $Δ$ suffers an abrupt decrease around the transition point, even reaching large negative values ( $Δ ≃ - 0.35$ ), in marked contrast to current studies pointing out a smooth behavior with $Δ ≳ 0$ at all densities. Besides, we characterize the behavior of {the recently defined} conformal factor, $d_{c}$ , in our four categories of twin stars for which we perform comparisons with theoretical constraints put, e.g. by Bayesian studies sometimes adjusted to agree with perturbative QCD at high densities. These analyses allow us to hypothesize modifications in the strong QCD coupling in dense nuclear matter with a strong thermodynamic discontinuity.
Comments:
v2: 21 pages, 10 figures. Some technical details and minor clarifications were added. It matches the PRD version
Subjects:
High Energy Physics — Phenomenology (hep-ph); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2408.11614 [pdf]
PRD(2024)·22 citations

Affiliations

first authorsco-authorsvia INSPIRE

Towards a first principles light-front Hamiltonian for the nucleon

Photoproduction γp→f0​(980)p in an effective Lagrangian approach

Second-order spin hydrodynamics from Zubarev's nonequilibrium statistical operator formalism

Strong decays of P−wave doubly charmed and bottom baryons

How the QCD trace anomaly behaves at the core of twin stars?

Affiliations

Photoproduction $γ p \to f_{0} (980) p$ in an effective Lagrangian approach

Strong decays of $P -$ wave doubly charmed and bottom baryons