Nuclear Theory·nucl-th

Thursday·April 4, 2019

11 papers—6 primary·5 cross-listed

01
Importance of $α$ -induced reactions and the inverse $(γ, α)$ on $p$ -nuclei
Chirashree Lahiri
We have calculated astrophysical reaction cross-sections for $(γ, α)$ reactions of some nuclei important for the calculation of $p$ -process reaction-decay network. Reaction rates for $α$ -induced reactions are calculated with the semi-microscopic optical potential constructed using double folding method, where nuclear density distributions for finite nuclei along with the effective nucleon-nucleon interaction are the important components of the folded potential. For this purpose density distributions of target nuclei are obtained from relativistic mean field approach. Astrophysical reaction cross section for elastic scattering of $α$ -particle from $^{92}$ Mo target is compared with the existing experimental results to constrain the newly formed potential. Further, to check the credibility of the present theoretical framework, the astrophysical S-factor for ( $α$ , $γ$ ) reactions are compared with the experimental observation, wherever available. Finally, an estimate of dominant photodisintegration channels at various astrophysical temperature is discussed for $p$ -nuclei $^{74}$ Se and $^{96}$ Ru.
nucl-thMod.Phys.Lett.A(2019)·0 citations
02
Simulating chiral anomalies with spin dynamics
Wen-Hao Zhou🇨🇳 · Jun Xu🇨🇳
Considering that the chiral kinetic equations of motion (CEOM) can be derived from the spin kinetic equations of motion (SEOM) for massless particles with approximations, we simulate the chiral anomalies by using the latter in a box system with the periodic boundary condition under a uniform external magnetic field. We found that the chiral magnetic effect is weaker while the damping of the chiral magnetic wave is stronger from the SEOM compared with that from the CEOM. In addition, effects induced by chiral anomalies from the SEOM are less sensitive to the decay of the magnetic field than from the CEOM due to the spin relaxation process.
nucl-thhep-phPLB(2019)·15 citations
03
Hydrodynamics with spin --- recent developments
Wojciech Florkowski🇵🇱
Recent theoretical developments in hydrodynamics of particles with spin 1/2 are briefly reviewed.
nucl-thhep-phActa Phys.Polon.B(2019)·2 citations
04
On the Stability of $Λ (1405)$ Matter
J. Hrtánková🇨🇿 · N. Barnea🇮🇱 · E. Friedman🇮🇱 · A. Gal🇮🇱 · J. Mareš🇨🇿 · M. Schäfer🇨🇿
A hypothesis of absolutely stable strange hadronic matter composed of $Λ (1405)$ baryons, here denoted $Λ^{*}$ , is tested within many-body calculations performed using the Relativistic Mean-Field approach. In our calculations, we employed the $Λ^{*} Λ^{*}$ interaction compatible with the $Λ^{*} Λ^{*}$ binding energy $B_{Λ^{*} Λ^{*}} = 40$ ~MeV given by the phenomenological energy-independent $K ˉ N$ interaction model by Yamazaki and Akaishi (YA). We found that the binding energy per $Λ^{*}$ , as well as the central density in $Λ^{*}$ many-body systems saturates for mass number $A \geq 120$ , leaving $Λ^{*}$ aggregates highly unstable against strong interaction decay. Moreover, we confronted the YA interaction model with kaonic atom data and found that it fails to reproduce the $K^{-}$ single-nucleon absorption fractions at rest from bubble chamber experiments.
nucl-thAIP Conf.Proc.(2019)·0 citations
05
Constraining the Hadron-Quark Phase Transition Chemical Potential via Astronomical Observation
Zhan Bai🇨🇳 · Yu-xin Liu🇨🇳
We investigate the chemical potential and baryon number density of the hadron-quark phase transition in neutron star matter. The hadron matter is described with relativistic mean field theory, and the quark matter is described with the Dyson-Schwinger equation approach of QCD. In order to study the first-order phase transition, we develop the sound speed interpolation scheme to construct the equation of state in the middle density region where the hadron phase and quark phase coexist. The phase transition chemical potential is constrained with the maximum mass, the tidal deformability and the radius of neutrons stars. And the most probable value of the phase transition chemical potential is found.
nucl-thastro-ph.HEAIP Conf.Proc.(2019)·3 citations
06
Implications from GW170817 for $Δ$ -isobar admixed hypernuclear compact stars
Jia Jie Li (ITP, Frankfurt)🇩🇪 · Armen Sedrakian (FIAS)🇩🇪
The effects of $Δ$ isobars on the equation of state of dense matter and structure of compact stars (CSs) are explored within the covariant density functional theory and confronted with the data on tidal deformability (TD) extracted from the GW170817 event. We show that the presence of $Δ$ isobars substantially softens the tension between the predictions of the hypernuclear density functionals and the inference from the observations of relatively small radius and small TD of canonical mass CSs. The TDs deduced from GW170817 are compatible with the existence of hypernuclear CSs containing an admixture of $Δ$ isobars. We thus argue that the GW170817 event is consistent with a merger of a binary CS system having both strangeness (hyperons) and $Δ$ isobars in the stellar core.
nucl-thastro-ph.HEhep-phApJL(2019)·89 citations
07
Nuclear correlations and modifications of the nucleon-nucleon potential due to the QCD critical mode
Juan M. Torres-Rincon🇺🇸 · Edward Shuryak🇺🇸
The scalar-isoscalar mode of QCD becomes lighter/nearly massless close to the chiral transition/second-order critical point. From nuclear physics we know that this mode is the main responsible for the attractive part of the nucleon-nucleon potential at inter-particle distances of 1-2 fm. Therefore one expects that close to the critical point there is a long-range strong attraction among nucleons. Using a Walecka-Serot model for the NN potential we study the effects of the critical point in a finite system of nucleons and mesons by solving classical Molecular Dynamics+Langevin equations for the freeze-out conditions of heavy-ion collisions. Going beyond the mean-field approximation allows us to account for strong nucleon correlations in the time evolution, leading to baryon clustering. We observe that light cluster formation, together with an enhancement of higher-order cumulants of the proton distribution can signal the presence of the critical point.
↳ hep-phnucl-thPoS(2019)·1 citation
08
On the convergence of chiral expansions for charmed meson masses in the up, down and strange quark masses
Matthias F.M. Lutz🇩🇪 · Xiao-Yu Guo🇩🇪 · Yonggoo Heo🇹🇭
We discuss the convergence properties of chiral expansions for the pseudoscalar and vector charmed meson masses based on the chiral SU(3) Lagrangian. Conventional expansion strategies as formulated in terms of bare meson masses are shown to suffer from poor convergence properties. This changes once the expansion is set up in terms of on-shell masses. We find a rapid convergence of the chiral expansion from vanishing quark masses up to physical values of the strange quark mass in this case. Detailed results are presented at the one-loop level for the D-meson and D^*-meson masses. It is emphasized that our results do not depend on the renormalization scale. An approximation hierarchy for the chiral Ward identities of QCD is obtained that keeps the proper form of low-energy branch points and cuts as they are implied by the use of on-shell masses. Given such a scheme we analyzed the charmed meson masses as available on various QCD lattice ensembles. In terms of the determined low-energy constants we consider the coupled-channel interactions of the Goldstone bosons with open-charm mesons. For the isospin violating hadronic decay width of the D_{s0}^*(2317) we predict the range (104-116) keV.
↳ hep-phnucl-thPoS(2019)·0 citations
09
Anomalous magnetohydrodynamics with longitudinal boost invariance and chiral magnetic effect
Irfan Siddique🇨🇳 · Ren-jie Wang🇨🇳 · Shi Pu🇨🇳 · Qun Wang🇨🇳
We study relativistic magnetohydrodynamics with longitudinal boost invariance in the presence of chiral magnetic effects and finite electric conductivity. With initial magnetic fields parallel or anti-parallel to electric fields, we derive the analytic solutions of electromagnetic fields and the chiral number and energy density in an expansion of several parameters determined by initial conditions. The numerical solutions show that such analytic solutions work well in weak fields or large chiral fluctuations. We also discuss the properties of electromagnetic fields in the laboratory frame.
↳ hep-phnucl-thPRD(2019)·40 citations
10
QCD-like phase diagram with Efimov trimers and Cooper pairs in resonantly interacting SU(3) Fermi gases
Hiroyuki Tajima🇯🇵 · Pascal Naidon🇯🇵
We investigate color superfluidity and trimer formation in resonantly interacting SU(3) Fermi gases with a finite interaction range. The finite range is crucial to avoid the Thomas collapse and treat the Efimov effect occurring in this system. Using the Skorniakov-Ter-Martirosian (STM) equation with medium effects, we show the effects of the atomic Fermi distribution on the Efimov trimer energy at finite temperature. We show the critical temperature of color superfluidity within the non-selfconsistent $T$ -matrix approximation (TMA). In this way, we can provide a first insight into the phase diagram as a function of the temperature $T$ and the chemical potential $μ$ . This phase diagram consists of trimer, normal, and color-superfluid phases, and is similar to that of quantum chromodynamics (QCD) at finite density and temperature, indicating a possibility to simulate the properties of such extremely dense matter in the laboratory.
↳ cond-mat.quant-gascond-mat.supr-conhep-thnucl-thNew J.Phys.(2019)·12 citations
11
Reliable estimation of the radius of convergence in finite density QCD
Matteo Giordano🇭🇺 · Attila Pásztor🇭🇺
We study different estimators of the radius of convergence of the Taylor series of the pressure in finite density QCD. We adopt the approach in which the radius of convergence is estimated first in a finite volume, and the infinite-volume limit is taken later. This requires an estimator for the radius of convergence that is reliable in a finite volume. Based on general arguments about the analytic structure of the partition function in a finite volume, we demonstrate that the ratio estimator cannot work in this approach, and propose three new estimators, capable of extracting reliably the radius of convergence, which coincides with the distance from the origin of the closest Lee-Yang zero. We also provide an estimator for the phase of the closest Lee-Yang zero, necessary to assess whether the leading singularity is a true critical point. We demonstrate the usage of these estimators on a toy model, namely 4 flavors of unimproved staggered fermions on a small $6^{3} \times 4$ lattice, where both the radius of convergence and the Taylor coefficients to any order can be obtained by a direct determination of the Lee-Yang zeros. Interestingly, while the relative statistical error of the Taylor expansion coefficients steadily grows with order, that of our estimators stabilizes, allowing for an accurate estimate of the radius of convergence. In particular, we show that despite the more than 100\% error bars on high-order Taylor coefficients, the given ensemble contains enough information about the radius of convergence.
↳ hep-latcond-mat.stat-mechhep-phnucl-thPRD(2019)·48 citations

Affiliations

first authorsco-authorsvia INSPIRE