Nuclear Theory·nucl-th

Wednesday·January 3, 2024

6 papers—4 primary·2 cross-listed

01
[Submitted on 1 Jan 2024]
Exploring the partonic collectivity in small systems at the LHC
Yuanyuan Wang · Wenbin Zhao · Huichao Song
Using the Hydro-Coal-Frag model that combines hydrodynamics at low $p_{T}$ , quark coalescence at intermediate $p_{T}$ , and the LBT transport model at high $p_{T}$ , we study the spectra and elliptic flow of identified hadrons in high multiplicity p--Pb and p--p collisions at the Large Hadron Collider (LHC). In p--Pb collisions, the Hydro-Coal-Frag model gives a good description of the differential elliptic flow over the $p_{T}$ range from 0 to 6 GeV and the approximate number of constituent quark (NCQ) scaling at intermediate $p_{T}$ . Although Hydro-Coal-Frag model can also roughly describe the elliptic flow in high multiplicity p--p collisions with the quark coalescence process, the larger contribution from the string fragmentations leads to a notable violation of the NCQ scaling of $v_{2}$ at intermediate $p_{T}$ as observed in the experiment. Comparison runs of the Hydro-Frag model without the coalescence process demonstrate that regardless the parameter adjustments, the Hydro-Frag model cannot simultaneously describe the $p_{T}$ spectra and the elliptic flow of identified hadrons in either p--Pb collisions or p--p collisions. The calculations in this paper thus provide support for the existence of partonic degrees of freedom and the possible formation of the QGP in the small systems created at the LHC.
Comments:
9 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2401.00913 [pdf]
PRC(2026)·12 citations
02
[Submitted on 1 Jan 2024]
Symmetry-projected variational calculations with the numerical suite TAURUS II. Configuration mixing of symmetry-projected reference states
Benjamin Bally🇫🇷 · Tomás R. Rodríguez🇪🇸
We present the numerical codes TAURUS_pav and TAURUS_mix that, combined, perform the configuration mixing of symmetry-projected real general Bogoliubov quasiparticle states represented in a spherical harmonic oscillator basis. The model space considered is invariant under spatial and isospin rotations but no specific set of orbits is assumed such that the codes can carry out both valence-space and no-core calculations. In addition, no number parity is assumed for the Bogoliubov quasiparticle states such that the codes can be used to describe even-even, odd-even and odd-odd nuclei. To demonstrate the potential of the codes, we perform an example no-core calculation of $^{24}$ Mg using a modern microscopic interaction.
Comments:
16 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2401.00941 [pdf]
EPJA(2024)·11 citations
03
[Submitted on 2 Jan 2024]
The reaction $π N \to ω N$ in a dynamical coupled-channel approach
Yu-Fei Wang🇩🇪
This talk is on a refined investigation on light flavor meson-baryon scatterings, using a dynamical coupled-channel approach, i.e. the Jülich-Bonn model. The previous channel space of $π N$ , $π Δ$ , $σ N$ , $ρN$ , $η N$ , $K Λ$ and $K Σ$ is extended by adding the $ω N$ final state. The spectra of $N^{*}$ and $Δ$ resonances are extracted, based on the result of a global fit to a worldwide collection of data, in the energy region from the $π N$ threshold to center-of-mass energy $z = 2.3$ GeV (approximately $300$ parameters against $9000$ data points). A negative value of the $ω N$ elastic spin-averaged scattering length has been extracted.
Comments:
4 pages, 2 figures, 17th International Workshop on Meson Physics (MESON2023), text overlaps with arXiv:2208.03061 [nucl-th]
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Computational Physics (physics.comp-ph)
arXiv:
2401.01186 [pdf]
EPJ Web Conf.(2024)·3 citations
04
[Submitted on 2 Jan 2024]
On the nature of the $N^{*}$ and $Δ$ resonances via coupled-channel dynamics
Yu-Fei Wang🇩🇪
This talk focuses on a recent work aiming at determining the composition of certain $N^{*}$ and $Δ$ resonances, i.e. whether they are compact states formed directly by quarks and gluons, or composite generated from the meson-baryon interaction. The information of the resonance poles is provided by a comprehensive coupled-channel approach, the Jülich-Bonn model. Thirteen states that are significant in this approach are studied. Two criteria for each state are adopted in this paper, the comparison thereof roughly indicates the model uncertainties. It is found that the conclusions for eight resonances are relatively certain: $N (1535) \frac{1}{2}^{-}$ , $N (1440) \frac{1}{2}^{+}$ , $N (1710) \frac{1}{2}^{+}$ , and $N (1520) \frac{3}{2}^{-}$ tend to be composite; whereas $N (1650) \frac{1}{2}^{-}$ , $N (1900) \frac{3}{2}^{+}$ , $N (1680) \frac{5}{2}^{+}$ , and $Δ (1600) \frac{3}{2}^{+}$ tend to be compact.
Comments:
6 pages, 2 figures, 16th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon (MENU 2023), text overlaps with arXiv:2307.06799 [nucl-th]
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2401.01191 [pdf]
EPJ Web Conf.(2024)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE

Exploring the partonic collectivity in small systems at the LHC

Symmetry-projected variational calculations with the numerical suite TAURUS II. Configuration mixing of symmetry-projected reference states

The reaction πN→ωN in a dynamical coupled-channel approach

On the nature of the N∗ and Δ resonances via coupled-channel dynamics

Affiliations

The reaction $π N \to ω N$ in a dynamical coupled-channel approach

On the nature of the $N^{*}$ and $Δ$ resonances via coupled-channel dynamics