Nuclear Theory·nucl-th

Friday·January 20, 2023

12 papers—7 primary·5 cross-listed

08
[Submitted on 18 Jan 2023] (cross-list from hep-ph)
Target mass corrections in lepton--nucleus DIS: theory and applications to nuclear PDFs
R. Ruiz🇵🇱 · K. F. Muzakka🇩🇪 · C. Leger🇫🇷 · P. Risse🇩🇪 · A. Accardi🇺🇸 · P. Duwentäster🇩🇪 · T. J. Hobbs🇺🇸 · T. Ježo🇩🇪 · C. Keppel🇺🇸 · M. Klasen🇩🇪 · K. Kovařík🇩🇪 · A. Kusina🇵🇱 and 5 other authors
Motivated by the wide range of kinematics covered by current and planned deep-inelastic scattering (DIS) facilities, we revisit the formalism, practical implementation, and numerical impact of target mass corrections (TMCs) for DIS on unpolarized nuclear targets. An important aspect is that we only use nuclear and later partonic degrees of freedom, carefully avoiding a picture of the nucleus in terms of nucleons. After establishing that formulae used for individual nucleon targets $(p, n)$ , derived in the Operator Product Expansion (OPE) formalism, are indeed applicable to nuclear targets, we rewrite expressions for nuclear TMCs in terms of \mbox{re-scaled} (or averaged) kinematic variables. As a consequence, we find a representation for nuclear TMCs that is approximately independent of the nuclear target. We go on to construct a single-parameter fit for all nuclear targets that is in good numerical agreement with full computations of TMCs. We discuss in detail qualitative and quantitative differences between nuclear TMCs built in the OPE and the parton model formalisms, as well as give numerical predictions for current and future facilities.
Comments:
journal version: 96 pages (including two appendices and references), many plots and figures, extended/improved discussions
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2301.07715 [pdf]
PPNP(2024)·33 citations
09
[Submitted on 18 Jan 2023] (cross-list from hep-ph)
Nucleon Resonance Electroexcitation Amplitudes and Emergent Hadron Mass
Daniel S. Carman🇺🇸 · Ralf W. Gothe🇺🇸 · Victor I. Mokeev🇺🇸 · Craig D. Roberts🇨🇳
Understanding the strong interaction dynamics that govern the emergence of hadron mass (EHM) represents a challenging open problem in the Standard Model. In this paper we describe new opportunities for gaining insight into EHM from results on nucleon resonance ( $N^{*}$ ) electroexcitation amplitudes (i.e. $γ_{v} p N^{*}$ electrocouplings) in the mass range up to 1.8\,GeV for virtual photon four-momentum squared (i.e. photon virtualities $Q^{2}$ ) up to 7.5\,GeV $^{2}$ available from exclusive meson electroproduction data acquired during the 6-GeV era of experiments at Jefferson Laboratory (JLab). These results, combined with achievements in the use of continuum Schwinger function methods (CSMs), offer new opportunities for charting the momentum dependence of the dressed quark mass from results on the $Q^{2}$ -evolution of the $γ_{v} p N^{*}$ electrocouplings. A successful description of the $Δ (1232) 3/ 2^{+}$ and $N (1440) 1/ 2^{+}$ electrocouplings has been achieved using CSMs with, in both cases, common momentum-dependent mass functions for the dressed quarks, for the gluons, and the same momentum-dependent strong coupling. Parameter-free CSM predictions for the electrocouplings of the $Δ (1600) 3/ 2^{+}$ became available in 2019. The experimental results obtained in the first half of 2022 have confirmed the CSM predictions. We also discuss prospects for these studies during the 12-GeV era at JLab using the CLAS12 detector, with experiments that are currently in progress, and canvass the physics motivation for continued studies in this area with a possible increase of the JLab electron beam energy up to 22\,GeV.
Comments:
23 pages, 11 figures, 2 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2301.07777 [pdf]
Particles(2023)·46 citations
10
[Submitted on 19 Jan 2023] (cross-list from hep-lat)
Nucleon form factors and the pion-nucleon sigma term
Rajan Gupta🇺🇸 · Tanmoy Bhattacharya🇺🇸 · Vincenzo Cirigliano🇺🇸 · Martin Hoferichter🇨🇭 · Yong-Chull Jang🇺🇸 · Balint Joo🇺🇸 · Emanuele Mereghetti🇺🇸 · Santanu Mondal🇺🇸 · Sungwoo Park🇺🇸 · Frank Winter🇺🇸 · Boram Yoon🇺🇸
This talk summarizes the progress made since Lattice 2021 in understanding and controlling the contributions of towers of multihadron excited states with mass gaps starting lower than of radial excitations, and in increasing our confidence in the extraction of ground state nucleon matrix elements. The most clear evidence for multihadron excited state contributions (ESC) is in axial/pseudoscalar form factors that are required to satisfy the PCAC relation between them. The talk examines the broader question--which and how many of the theoretically allowed positive parity states $N (p) π (- p)$ , $N (0) π (0) π (0)$ , $N (p) π (0)$ , $N (0) π (p), \dots$ make significant contributions to a given nucleon matrix element? New data for the axial, electric and magnetic form factors are presented. They continue to show trends observed in Ref[1]. The N $^{2}$ LO $χ$ PT analysis of the ESC to the pion-nucleon sigma term, $σ_{π N}$ , has been extended to include the $Δ$ as an explicit degree of freedom [2]. The conclusion reached in Ref [3] that $N π$ and $N π π$ states each contribute about 10 MeV to $σ_{π N}$ , and the consistency between the lattice result with $N π$ state included and the phenomenological estimate is not changed by this improvement.
Comments:
10 pages, 5 figures. Talk presented at the 39th International Symposium on Lattice Field Theory (LATTICE2022) 8-3 August, 2022 Bonn, Germany. arXiv admin note: text overlap with arXiv:2203.05647
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2301.07885 [pdf]
PoS(2023)·5 citations
11
[Submitted on 19 Jan 2023] (cross-list from hep-ph)
Three-dimensional QCD phase diagram in the pNJL model
Lu-Meng Liu🇨🇳 · Jun Xu🇨🇳 · Guang-Xiong Peng🇨🇳
Based on the three-flavor Polyakov-looped Nambu $-$ Jona-Lasinio (pNJL) model, we have studied the structure of the three-dimensional QCD phase diagram with respect to the temperature, the baryon chemical potential, and the isospin chemical potential, by investigating the interplay among the chiral quark condensate, the pion condensate, and the Polyakov loop. While the pNJL model leads to qualitatively similar structure of the normal quark phase, the pion superfluid phase, and the Sarma phase as well as their phase boundaries, when compared to the NJL model, the inclusion of the Polyakov loop enlarges considerably the areas of the pion superfluid phase and the Sarma phase, and leads to critical end points at higher temperatures. With the contribution of the gluon dynamics effectively included, the present study is expected to give a more reliable prediction of the three-dimensional QCD phase diagram compared to that in the NJL model.
Comments:
8 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2301.07900 [pdf]
Nucl.Phys.Rev.(2023)·7 citations
12
[Submitted on 19 Jan 2023] (cross-list from hep-ph)
Relations for low-energy constants in baryon chiral perturbation theory with explicit $Δ (1232)$ derived from the chiral quark model
Jun Jiang🇨🇳 · Shao-Zhou Jiang🇨🇳 · Shi-Yuan Li🇨🇳 · Yan-Rui Liu🇨🇳 · Zong-Guo Si🇨🇳 · Hong-Qian Wang🇨🇳
We study the relations between low-energy constants (LECs) in the chiral Lagrangians with $Δ (1232)$ and those in the quark-level description model up to the third chiral order. Ten structure correspondences are involved in getting the relations. This situation is more complicated than the spin-1/2 baryon case. The obtained results may help to further investigations involving the $Δ (1232)$ baryons.
Comments:
Version accepted by Eur. Phys. J. C. 10 pages, 2 figures, 4 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2301.08059 [pdf]
EPJC(2023)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE

Target mass corrections in lepton--nucleus DIS: theory and applications to nuclear PDFs

Nucleon Resonance Electroexcitation Amplitudes and Emergent Hadron Mass

Nucleon form factors and the pion-nucleon sigma term

Three-dimensional QCD phase diagram in the pNJL model

Relations for low-energy constants in baryon chiral perturbation theory with explicit Δ(1232) derived from the chiral quark model

Affiliations

Relations for low-energy constants in baryon chiral perturbation theory with explicit $Δ (1232)$ derived from the chiral quark model