Nuclear Theory·nucl-th

Tuesday·April 16, 2019

13 papers—9 primary·4 cross-listed

10
On the two-body decay processes of the predicted three-body $K^{*} (4307)$ resonance
Xiu-Lei Ren🇩🇪 · Brenda B. Malabarba🇧🇷 · K. P. Khemchandani🇧🇷 · A. Martinez Torres🇧🇷
In a recent theoretical work, Phys. Lett. B785, 112 (2018), we proposed that a $K^{*}$ resonance with hidden charm content arises from the $K D D ˉ^{*}$ dynamics, where the $D D ˉ^{*}$ system is treated as a $Z_{c} (3900)$ or $X (3872)$ . With the motivation of determining its further properties, which can be observed in experiments, we now present a calculation of the decay processes of this $K^{*}$ , namely $K^{*} (4307)$ , to two-body channels. Particularly, we consider the decay channels $J / ψ K^{*} (892)$ , $D ˉ D_{s}$ , $D ˉ D_{s}^{*}$ and $D ˉ^{*} D_{s}^{*}$ . The mechanisms of the decay to these channels involve triangular loops and are a consequence of the internal structure of the state. Thus, the values found for the decay widths of the proposed $K^{*} (4307)$ are related to its nature and should be valuable for carrying on an experimental study of the $K^{*} (4307)$ . A $K^{*}$ state with such a mass (in the charmonium region) and quantum numbers is a clear manifestation of an exotic meson, since, having hidden charm (i.e., a $c c ˉ$ pair), its mass and quantum numbers can not be explained within a quark-antiquark description.
↳ hep-phnucl-thJHEP(2019)·14 citations
11
Wiedemann-Franz Law For Hot QCD Matter in a Color String Percolation Scenario
Pragati Sahoo🇮🇳 · Raghunath Sahoo🇮🇳 · Swatantra Kumar Tiwari🇮🇳
Transport coefficients serve as important probes in characterizing the QCD matter created in high-energy heavy-ion collisions. Thermal and electrical conductivities as transport coefficients have got special significance in studying the time evolution of the created matter. We have adopted color string percolation approach for the estimation of thermal conductivity ( $κ$ ), electrical conductivity ( $σ_{e l}$ ) and their ratio, which is popularly known as Wiedemann-Franz law in condensed matter physics. The ratio $κ / σ_{e l} T$ , which is also known as Lorenz number ( $L$ ) is studied as a function of temperature and is compared with various theoretical calculations. We observe that the thermal conductivity for hot QCD medium is almost temperature independent in the present formalism and matches with the results obtained in ideal equation of state (EOS) for quark-gluon plasma with fixed coupling constant ( $α_{s}$ ). The obtained Lorenz number is compared with the Stefan-Boltzmann limit for an ideal gas. We observe that a hot QCD medium with color degrees of freedom behaves like a free electron gas.
↳ hep-phnucl-thPRD(2019)·13 citations
12
Constraining the neutron star equation of state using Pulse Profile Modeling
Anna L. Watts
One very promising technique for measuring the dense matter Equation of State exploits hotspots that form on the neutron star surface due to the pulsar mechanism, accretion streams, or during thermonuclear explosions in the neutron star ocean. This article explains how Pulse Profile Modeling of hotspots is being used by the Neutron Star Interior Composition Explorer (NICER), an X-ray telescope installed on the International Space Station in 2017 - and why the technique is a mission driver for the next, larger-area generation of telescopes including the enhanced X-ray Timing and Polarimetry (eXTP) mission and the Spectroscopic Time-Resolving Observatory for Broadband Energy X-rays (STROBE-X).
↳ astro-ph.HEastro-ph.SRgr-qcnucl-thAIP Conf.Proc.(2019)·40 citations
13
Baryon sigma terms in SU(3) BChPT x 1/Nc
Ishara P. Fernando🇺🇸 · Jose L. Goity🇺🇸
ChPT and the $1/ N_{c}$ expansion provide systematic frameworks for the strong interactions at low energy. A combined framework of both expansions has been developed and applied for baryons with three light-quark-flavors. The small scale expansion of the combined approach is identified as the $ξ$ -expansion, in which the power counting of the expansions is linked according to $O (p) = O (1/ N_{c}) = O (ξ)$ . The physical baryon masses as well as lattice QCD baryon masses for different quark mass masses are analyzed to $O (ξ^{3})$ in that framework. $σ$ terms are addressed using the Feynman Hellmann theorem. For the nucleon, a useful connection between the deviation of the Gell-Mann-Okubo relation and the $σ$ term $σ_{8 N}$ associated with the scalar density $u ˉ u + d ˉ d - 2 s ˉ s$ is identified. In particular, the deviation from the tree level relation $σ_{8 N} = \frac{1}{3} (2 m_{N} - m_{Σ} - m_{Ξ})$ , which gives rise to the so called $σ$ -term puzzle, is studied in the $ξ$ -expansion. A large correction non-analytic in $ξ$ results for that relation, making plausible the resolution of the puzzle. Issues with the determination of the strangeness $σ$ terms are discussed, emphasizing the need for lattice calculations at smaller $m_{s}$ for better understanding the range of validity of the effective theory. The analysis presented here leads to $σ_{π N} = 69 (10)$ ~MeV and $σ_{π Δ} = 60 (10)$ ~MeV.
↳ hep-phnucl-thPoS(2019)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE

On the two-body decay processes of the predicted three-body K∗(4307) resonance

Wiedemann-Franz Law For Hot QCD Matter in a Color String Percolation Scenario

Constraining the neutron star equation of state using Pulse Profile Modeling

Baryon sigma terms in SU(3) BChPT x 1/Nc

Affiliations

On the two-body decay processes of the predicted three-body $K^{*} (4307)$ resonance