Nuclear Theory·nucl-th

Wednesday·April 22, 2020

13 papers—10 primary·3 cross-listed

11
[Submitted on 20 Apr 2020] (cross-list from astro-ph.HE)
Toward a unified equation of state for multi-messenger astronomy
Michał Marczenko🇵🇱 · David Blaschke🇵🇱 · Krzysztof Redlich🇵🇱 · Chihiro Sasaki🇵🇱
We present a first step in developing a benchmark equation-of-state (EoS) model for multi-messenger astronomy that unifies the thermodynamics of quark and hadronic degrees of freedom. A Lagrangian approach to the thermodynamic potential of quark-meson-nucleon (QMN) matter was used. In this approach, dynamical chiral-symmetry breaking is described by the scalar mean-field dynamics coupled to quarks and nucleons and their chiral partners, whereby its restoration occurs in the hadronic phase by parity doubling, as well as in the quark phase. Quark confinement was achieved by an auxiliary scalar field that parametrizes a dynamical infrared cutoff in the quark sector, serving as an ultraviolet cutoff for the nucleonic phase space. The gap equations were solved for the isospin-symmetric case, as well as for neutron star (NS) conditions. We also calculated the mass-radius (MR) relation of NSs and their tidal deformability parameter. The obtained EoS is in accordance with nuclear matter properties at saturation density and with the flow constraint from heavy ion collision experiments. For isospin-asymmetric matter, a sequential occurrence of light quark flavors is obtained, allowing for a mixed phase of chirally-symmetric nucleonic matter with deconfined down quarks. The MR relations and TDs for compact stars fulfill the constraints from the latest astrophysical observations for PSR J0740+6620, PSR J0030+0451, and the NS merger GW170817, whereby the tension between the maximum mass and compactness constraints rather uniquely fixes the model parameters. The model predicts the existence of stars with a core of chirally restored but purely hadronic (confined) matter for masses beyond $1.8 M_{⊙}$ . Stars with pure-quark matter cores are found to be unstable against the gravitational collapse. This instability is shifted to even higher densities if repulsive interactions between quarks are included.
Comments:
version accepted for publication in A&A
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2004.09566 [pdf]
Astron.Astrophys.(2020)·49 citations
12
[Submitted on 21 Apr 2020] (cross-list from hep-ph)
Quadruply charmed baryons as heavy quark symmetry partners of the $D_{s 0}^{*} (2317)$
Tian-Wei Wu🇨🇳 · Ming-Zhu Liu🇨🇳 · Li-Sheng Geng🇨🇳 · Emiko Hiyama🇯🇵 · Manuel Pavon Valderrama🇨🇳 · Wen-Ling Wang🇨🇳
Both unitary chiral theories and lattice QCD simulations show that the $D K$ interaction is attractive and can form a bound state, namely, $D_{s 0}^{*} (2317)$ . Assuming the validity of the heavy antiquark-diquark symmetry (HADS), the $Ξ_{cc} K ˉ$ interaction is the same as the $D K$ interaction, which implies the existence of a $Ξ_{cc} K ˉ$ bound state with a binding energy of $49 - 64$ MeV. In this work, we study whether a $Ξ_{cc} Ξ_{cc} K ˉ$ three-body system binds. The $Ξ_{cc} Ξ_{cc}$ interaction is described by exchanging $π$ , $σ$ , $ρ$ , and $ω$ mesons, with the corresponding couplings related to those of the $N N$ interaction via the quark model. We indeed find a $Ξ_{cc} Ξ_{cc} K ˉ$ bound state, with quantum numbers $J^{P} = 0^{-}$ , $I = \frac{1}{2}$ , $S = 1$ and $C = 4$ , and a binding energy of $80 - 118$ MeV. It is interesting to note that this system is very similar to the well-known $N N K ˉ$ system, which has been studied extensively both theoretically and experimentally. Within the same framework, we show the existence of a $N N K ˉ$ state with a binding energy of $35 - 43$ MeV, consistent with the results of other theoretical works and experimental data, which serves as a consistency check on the predicted $Ξ_{cc} Ξ_{cc} K ˉ$ bound state.
Comments:
12 pages, 2 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2004.09779 [pdf]
EPJC(2020)·14 citations
13
[Submitted on 21 Apr 2020] (cross-list from hep-ph)
Extraction of $N D$ scattering lengths from the $Λ_{b} \to π^{-} p D^{0}$ decay and properties of the $Σ_{c} (2800)^{+}$
Shuntaro Sakai🇨🇳 · Feng-Kun Guo🇨🇳 · Bastian Kubis🇩🇪
The isovector and isoscalar $N D$ $s$ -wave scattering lengths are extracted by fitting to the LHCb data of the $p D^{0}$ invariant-mass distribution in the decay $Λ_{b} \to π^{-} p D^{0}$ , making use of the cusp effect at the $n D^{+}$ threshold. The analysis is based on a coupled-channel nonrelativistic effective field theory. We find that the real part of the isovector $N D$ scattering length is unnaturally large due to the existence of a near-threshold state with a mass around 2.8 GeV. The state is consistent with the $Σ_{c} (2800)^{+}$ resonance observed at Belle. Our results suggest that it couples strongly to the $N D$ channel in an $s$ -wave, and that its quantum numbers are $J^{P} = 1/ 2^{-}$ . The strong cusp behavior at the $n D^{+}$ threshold can be verified using updated LHCb data.
Comments:
9 pages, 6 figures; version to be published in Phys. Lett. B
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2004.09824 [pdf]
PLB(2020)·21 citations

Affiliations

first authorsco-authorsvia INSPIRE

Toward a unified equation of state for multi-messenger astronomy

Quadruply charmed baryons as heavy quark symmetry partners of the Ds0∗​(2317)

Extraction of ND scattering lengths from the Λb​→π−pD0 decay and properties of the Σc​(2800)+

Affiliations

Quadruply charmed baryons as heavy quark symmetry partners of the $D_{s 0}^{*} (2317)$

Extraction of $N D$ scattering lengths from the $Λ_{b} \to π^{-} p D^{0}$ decay and properties of the $Σ_{c} (2800)^{+}$