Nuclear Theory·nucl-th

Thursday·September 9, 2021

9 papers—4 primary·5 cross-listed

05
[Submitted on 3 Sept 2021] (cross-list from hep-ph)
Effective Debye Screening Mass in an Anisotropic Quark Gluon Plasma
Lihua Dong🇨🇳 · Yun Guo🇨🇳 · Ajaharul Islam🇺🇸 · Michael Strickland🇺🇸
Due to the rapid longitudinal expansion of the quark-gluon plasma created in heavy-ion collisions, large local-rest-frame momentum-space anisotropies are generated during the system's evolution. These momentum-space anisotropies complicate the modeling of heavy-quarkonium dynamics in the quark-gluon plasma due to the fact that the resulting inter-quark potentials are spatially anisotropic, requiring real-time solution of the 3D Schrödinger equation. Herein, we introduce a method for reducing anisotropic heavy-quark potentials to isotropic ones by introducing an effective screening mass that depends on the quantum numbers $l$ and $m$ of a given state. We demonstrate that, using the resulting effective Debye screening masses, one can solve a 1D Schrödinger equation and reproduce the full 3D results for the energies and binding energies of low-lying heavy-quarkonium bound states to relatively high accuracy. The resulting effective isotropic potential models could provide an efficient method for including momentum-anisotropy effects in open quantum system simulations of heavy-quarkonium dynamics in the quark-gluon plasma.
Comments:
final version, published in PRD
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2109.01284 [pdf]
PRD(2021)·12 citations
06
[Submitted on 8 Sept 2021] (cross-list from hep-ph)
Novel description of $P_{c} (4312)^{+}$ , $P_{c} (4380)^{+}$ , and $P_{c} (4457)^{+}$ with double triangle cusps
Satoshi X. Nakamura🇺🇸
We propose a novel scenario for the peak structures, usually interpreted as hidden charm pentaquark ( $P_{c}$ ) contributions, in the LHCb's $Λ_{b}^{0} \to J / ψ p K^{-}$ data. The key idea is to utilize leading or lower-order singularities from double triangle mechanisms. The singularities cause anomalous threshold cusps, which are significantly more singular than the ordinary ones, at the $Σ_{c}^{(*)} D ˉ^{(*)}$ threshold. We demonstrate that the double triangle amplitudes interfere with other common mechanisms to create peak structure that fit well the $P_{c} (4312)^{+}$ , $P_{c} (4380)^{+}$ , and $P_{c} (4457)^{+}$ peaks in the data. This picture is completely different from commonly used ones such as hadron molecules and compact pentaquarks. Meanwhile, $P_{c} (4440)^{+}$ is included in the proposed model as a resonance with width and strength significantly smaller than previously estimated. The proposed model can (partly) explain the current data for other processes where $P_{c}^{+}$ signals are expected such as: no $P_{c}^{+}$ signals in the GlueX $J / ψ$ photoproduction data; a possible signal only from $P_{c} (4440)^{+}$ in the LHCb's $Λ_{b}^{0} \to J / ψ p π^{-}$ data.
Comments:
6 pages, 4 figures, Contribution to the Proceedings for 10th International Workshop on Charm Physics (CHARM 2020), May 31-June 5 2021, Mexico City, Mexico
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2109.03456 [pdf]
PoS(2021)·3 citations
07
[Submitted on 8 Sept 2021] (cross-list from hep-ph)
Asymmetric longitudinal flow decorrelations in proton-nucleus collisions
Xiang-Yu Wu🇨🇳 · Guang-You Qin🇨🇳
We perform the first study on asymmetric longitudinal decorrelations of elliptic, triangular and quadrangular flows in proton-nucleus collisions at the LHC and RHIC energies. To measure the longitudinal flow decorrelations for asymmetric collision systems, we propose a new set of rapidity-asymmetric flow decorrelation functions. Our event-by-event hydrodynamic calculations show that the flow decorrelations in proton-going direction are larger than those in nucleus-going direction. We also find that proton-nucleus collisions at RHIC have larger longitudinal flow decorrelation effects than those at the LHC. Our study opens a new window to probe the longitudinal properties and the origin of flows in relativistic nuclear collisions.
Comments:
6 pages, 3 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2109.03512 [pdf]
13 citations
08
[Submitted on 8 Sept 2021] (cross-list from hep-ph)
Gluon EMC effects in nuclear matter
Xuan-Gong Wang🇦🇺 · Wolfgang Bentz🇯🇵 · Ian C. Cloët🇺🇸 · Anthony W. Thomas🇦🇺
We investigate the gluonic structure of nuclei within a mean-field model of nuclear structure based upon the modification of the structure of a bound nucleon, with the nucleon described by the Nambu--Jona-Lasinio model. This approach has been shown to reproduce the European Muon Collaboration (EMC) effect, involving the ratio of the spin-independent structure functions of a heavier nucleus to that of the deuteron. It also predicts a significant nuclear modification for the spin structure functions, known as the polarized EMC effect. Here we report sizeable nuclear modifications of the gluon distributions (a "gluon EMC effect") for the ratios of both the unpolarized and polarized gluon distributions in nuclear matter to those of a free nucleon.
Comments:
11 pages, 3 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2109.03591 [pdf]
J.Phys.G(2022)·11 citations
09
[Submitted on 8 Sept 2021] (cross-list from astro-ph.HE)
Bosonic Dark Matter in Neutron Stars and its Effect on Gravitational Wave Signal
Davood Rafiei Karkevandi🇮🇷 · Soroush Shakeri🇮🇷 · Violetta Sagun🇵🇹 · Oleksii Ivanytskyi🇵🇱
We study an impact of self-interacting bosonic dark matter (DM) on various observable properties of neutron stars (NSs). The analysis is performed for asymmetric DM with masses from few MeV to GeV, the self-coupling constant of order $O (1)$ and various DM fractions. Allowing a mixture between DM and baryonic matter, the formation of a dense DM core or an extended dark halo have been explored. We find that both distribution regimes crucially depend on the mass and fraction of DM for sub-GeV boson masses in the strong coupling regime. From the combined analysis of the mass-radius relation and the tidal deformability of compact stars including bosonic DM, we set a stringent constraint on DM fraction. We conclude that observations of 2 $M_{⊙}$ NSs together with $Λ_{1.4} \leq 580$ constraint, set by LIGO/Virgo Collaboration, favour sub-GeV DM particles with low fractions below $\sim 5%$ .
Comments:
18 pages, 17 figures, matches the published version in PRD
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2109.03801 [pdf]
PRD(2022)·198 citations

Affiliations

first authorsco-authorsvia INSPIRE

Effective Debye Screening Mass in an Anisotropic Quark Gluon Plasma

Novel description of Pc​(4312)+, Pc​(4380)+, and Pc​(4457)+ with double triangle cusps

Asymmetric longitudinal flow decorrelations in proton-nucleus collisions

Gluon EMC effects in nuclear matter

Bosonic Dark Matter in Neutron Stars and its Effect on Gravitational Wave Signal

Affiliations

Novel description of $P_{c} (4312)^{+}$ , $P_{c} (4380)^{+}$ , and $P_{c} (4457)^{+}$ with double triangle cusps