Nuclear Theory·nucl-th

Monday·August 3, 2020

10 papers—4 primary·6 cross-listed

01
[Submitted on 31 Jul 2020]
Possible molecular states from the $N Δ$ interaction
Zhi-Tao Lu🇨🇳 · Han-Yu Jiang🇨🇳 · Jun He🇨🇳
Recently, a hint for dibaryon $N Δ (D_{21})$ was observed at WASA-AT-COSY with a mass about $30 \pm 10$ MeV below the $N Δ$ threshold. It has a relatively small binding energy compared with the $d^{*} (2380)$ and a width close to the width of the $Δ$ baryon, which suggests that it may be a dibaryon in a molecular state picture. In this work, we study the possible $S$ -wave molecular states from the $N Δ$ interaction within the quasipotential Bethe-Salpeter equation approach. The interaction is described by exchanging $π$ , $ρ$ , and $ω$ mesons. With reasonable parameters, a $D_{21}$ bound state can be produced from the interaction. The results also suggest that there may exist two more possible $D_{12}$ and $D_{22}$ states with smaller binding energies. The $π$ exchange is found to play the most important role to bind two baryons to form the molecular states. An experimental search for possible $N Δ (D_{12})$ and $N Δ (D_{22})$ states will be helpful for understanding the hint of the dibaryon $N Δ (D_{21})$ .
Comments:
7 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2007.15878 [pdf]
PRC(2020)·15 citations
02
[Submitted on 30 Jul 2020]
Low mass strange stars and the compact star 1E1207.4-5209 in the Field Correlator Method
F. I. M Pereira🇧🇷
We investigate the possible existence of anomalous mass defects in the low mass region of stellar sequences of strange stars. We employ the nonperturbative equation of state derived in the framework of the Field Correlator Method to describe the hydrostatic equilibrium of the strange matter. The large distance static $Q Q ˉ$ potential $V_{1}$ and the gluon condensate $G_{2}$ are the main parameters of the model. We use the surface gravitational redshift measurements as a probe to determine the ratio $(P / E)_{C}$ at the center of strange stars. For $V_{1} = 0$ and $G_{2} \gappr 0.035 GeV^{4}$ \,, we show that $(P / E)_{C} ≃ 0.262$ and the corresponding redshift $z_{S} ≃ 0.47$ are limiting values, at the maximum mass of the highest mass stellar sequence. As a direct application of our study, we try to determine the values of $V_{1}$ and $G_{2}$ from astrophysical observations of the compact star 1E\,1207.4-5209. Due to the uncertainties in the surface redshift determination, we made two attempts to obtain the model parameters. Our findings show that $(P / E)_{C} = 0.07 3_{+ 0.024}^{+ 0.029}$ \, at 68\% confidence, $V_{1} = 0.44 \pm 0.10$ \,GeV at 90\% confidence and $G_{2} = 0.008 \pm 0.001 GeV^{4}$ at 95\% confidence \, in the first attempt; and $(P / E)_{C} = 0.07 3_{+ 0.024}^{+ 0.029} = 0.087 \pm 0.028$ \, at 71\% confidence, $V_{1} = 0.43 \pm 0.085$ \,GeV at 94\% confidence and $G_{2} = 0.0093 \pm 0.00092 GeV^{4}$ at 94\% confidence in the second attempt. These values of $V_{1}$ and $G_{2}$ are in reasonable agreement with the lattice and QCD sum rules calculations. As a consequence of the high values of $V_{1}$ and $G_{2}$ , the anomalous mass defects of 1E\,1207.4-5209 are $∣ Δ_{2} M ∣ ≃ 2.56 \times 1 0^{53}$ \,erg\, in the first attempt and $∣ Δ_{2} M ∣ ≃ 2.94 \times 1 0^{53}$ \,erg\, in the second attempt.
Comments:
34 pages, 15 figures
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2007.16022 [pdf]
PRD(2021)·0 citations
03
[Submitted on 31 Jul 2020]
Linear stability of Israel-Stewart theory in the presence of net-charge diffusion
C. V. Brito🇧🇷 · G. S. Denicol🇧🇷
In this paper, we perform a linear stability analysis of Israel-Stewart theory around a global equilibrium state, including the effects of shear-stress tensor, net-baryon diffusion current and diffusion-viscous coupling. We find all the relevant modes of this theory and derive necessary conditions that these modes must satisfy in order to be stable and subluminal. With these conditions, we then derive constraints for the shear and diffusion relaxation times and the transport coefficients related to diffusion-viscous coupling.
Comments:
25 pages, 26 figures. Published version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Theory (hep-th)
arXiv:
2007.16141 [pdf]
PRD(2020)·46 citations
04
[Submitted on 22 Jul 2020]
Evidence for the general dominance of proton shells in low-energy fission
K. Mahata🇮🇳 · C. Schmitt🇫🇷 · Shilpi Gupta🇮🇳 · A. Shrivastava🇮🇳 · G. Scamps🇧🇪 · K.-H. Schmidt
A regular pattern, revealing the leading role of the light-fragment nuclear charge, is found to emerge from a consistent analysis of the experimental information collected recently on low-energy asymmetric fission of neutron-deficient nuclei around lead. The observation is corroborated by a theoretical investigation within a microscopic framework, suggesting the importance of proton configurations driven by quadrupole-octupole correlations. This is in contrast to the earlier theoretical interpretations in terms of dominant neutron shells. The survey of a wider area of the nuclear chart by a semi-empirical approach points to the lack of understanding of the competition between the different underlying macroscopic and microscopic forces in a quantitative manner. Combined with previously identified stabilizing forces, the present finding shows a striking connection between the "old" (actinide) and "new" (pre-actinide) islands of asymmetric fission which could steer the strive for an unified theory of fission.
Comments:
6 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2007.16184 [pdf]
PLB(2022)·56 citations

Affiliations

first authorsco-authorsvia INSPIRE

Possible molecular states from the NΔ interaction

Low mass strange stars and the compact star 1E1207.4-5209 in the Field Correlator Method

Linear stability of Israel-Stewart theory in the presence of net-charge diffusion

Evidence for the general dominance of proton shells in low-energy fission

Affiliations

Possible molecular states from the $N Δ$ interaction