Nuclear Theory·nucl-th

Friday·November 15, 2019

8 papers—3 primary·5 cross-listed

01
Subbarrier fusion reactions of an aligned deformed nucleus
K. Hagino · S. Sakaguchi
We discuss heavy-ion fusion reactions of a well-deformed odd-mass nucleus at energies around the Coulomb barrier. To this end, we consider the $^{16}$ O+ $^{165}$ Ho reaction and take into account the effect of deformation of $^{165}$ Ho using the orientation average formula. We show that fusion cross sections are sensitive to magnetic substates of the target nucleus, and cross sections for the side collision, which are relevant to a synthesis of superheavy elements, may be enhanced by a factor of around two by aligning the deformed target nuclei. We also discuss the effect of alignment on the fusion barrier distribution. We find that, for a particular choice of alignment, the shape of barrier distribution becomes similar to a typical shape of barrier distribution for a deformed nucleus with a negative hexadecapole deformation parameter, $β_{4}$ , even if the intrinsic $β_{4}$ is positive in the target nucleus.
nucl-thnucl-exPRC(2019)·8 citations
02
Three-body correlations in mesonic-atom-like systems
H. Moriya🇯🇵 · W. Horiuchi🇯🇵 · J.-M. Richard🇫🇷
Three-body correlations in three-body exotic atoms are studied with simple models that consist of three bosons interacting through a superposition of long- and short-range potentials. We discuss the correlations among particles by comparing the energy shifts given by precise three-body calculations and by the Deser-Trueman formula, in which the long- and short-range contributions are factorized. By varying the coupling of the short-range potential, we evaluate the ranges of the strength where the two-body correlations dominate and where the three-body correlations cannot be neglected.
nucl-thSciPost Phys.Proc.(2020)·3 citations
03
Statistical double $Λ$ hypernuclear formation from $Ξ^{-}$ absorption at rest in light nuclei
Akira Ohnishi🇯🇵 · Chikako Ishizuka🇯🇵 · Kohsuke Tsubakihara🇯🇵 · Yuichi Hirata🇯🇵
We investigate double $Λ$ hyperfragment formation from the statistical decay of double $Λ$ compound nuclei produced in the $Ξ^{-}$ absorption at rest in light nuclei, $^{12} C$ , $^{14} N$ and $^{16} O$ . We examine the target and the $ΛΛ$ bond energy dependence of the double $Λ$ hyperfragment formation probabilities, especially of those double hypernuclei observed in experiments. For the $^{12} C$ ( $^{14} N$ ) target, the formation probabilities of $_{ΛΛ}^{6} He$ and $_{ΛΛ}^{10} Be$ ( $_{ΛΛ}^{13} B$ ) are found to be reasonably large as they are observed in the KEK-E373 (KEK-E176) experiment. By comparison, for $^{16} O$ target, the formation probability of $_{ΛΛ}^{11} Be$ is calculated to be small with $Δ B_{ΛΛ}$ consistent with the Nagara event. We also evaluate the formation probability of $_{ΛΛ}^{5} H$ from a $Ξ^{-}$ - $^{6} He$ bound state, $_{Ξ}^{7} H$ .
nucl-thnucl-exPTEP(2020)·2 citations
04
Three-body losses of a polarized Fermi gas near a p-wave Feshbach resonance in effective field theory
Marcel Schmidt · Hans-Werner Hammer · Lucas Platter
We study three-body recombination of fully spin-polarized $^{6}$ Li atoms that are interacting resonantly in relative p-waves. Motivated by a recent experiment, we focus on negative scattering volumes where three atoms recombine into a deep dimer and another atom. We calculate the three-body recombination rate using a Faddeev equation derived from effective field theory. In particular, we study the magnetic field and temperature dependences of the loss rate and use the recombination data to determine the effective range of the p-wave atom-atom interaction. We also predict the existence of a shallow three-body bound state that manifests itself as a prominent feature in the energy-dependent three-body recombination rate.
↳ cond-mat.quant-gasnucl-thPRA(2020)·8 citations
05
Indirect Methods in Nuclear Astrophysics
Livius Trache · Florin Carstoiu
This paper follows the inaugural talk one of the authors (LT) gave at the opening of the ECT* workshop with the same title, which he co-organized in Trento, Italy, November 5-9, 2018. As such it follows the ideas expressed there, which were to out-line the discussions that the organizers intended for that meeting. Therefore, the paper will review the indirect methods in nuclear astrophysics, their use and their specific problems, old and new, the need to further developments rather than giving complete treatments of each method or reviewing exhaustively the existing literature. The workshop was from its inception aiming also at reviewing the status of the field of nuclear astrophysics and its connections with adjacent branches of physics. Some lines on these are included here.
↳ nucl-exnucl-th2 citations
06
$Ξ_{c}$ and $Ξ_{b}$ excited states within a $SU (6)_{lsf} \times$ HQSS model
J. Nieves🇪🇸 · R. Pavao🇪🇸 · L. Tolos🇩🇪
We study odd parity $J = 1/2$ and $J = 3/2$ $Ξ_{c}$ resonances using a unitarized coupled-channel framework based on a $SU (6)_{lsf} \times$ HQSS-extended Weinberg-Tomozawa baryon-meson interaction, while paying a special attention to the renormalization procedure. We predict a large molecular $Λ_{c} K ˉ$ component for the $Ξ_{c} (2790)$ with a dominant $0^{-}$ light-degree-of-freedom spin configuration. We discuss the differences between the $3/ 2^{-}$ $Λ_{c} (2625)$ and $Ξ_{c} (2815)$ states, and conclude that they cannot be SU(3) siblings, whereas we predict the existence of other $Ξ_{c} -$ states, two of them related to the two-pole structure of the $Λ_{c} (2595)$ . It is of particular interest a pair of $J = 1/2$ and $J = 3/2$ poles, which form a HQSS doublet and that we tentatively assign to the $Ξ_{c} (2930)$ and $Ξ_{c} (2970)$ , respectively. Within this picture, the $Ξ_{c} (2930)$ would be part of a SU(3) sextet, containing either the $Ω_{c} (3090)$ or the $Ω_{c} (3119)$ , and that would be completed by the $Σ_{c} (2800)$ . Moreover, we identify a $J = 1/2$ sextet with the $Ξ_{b} (6227)$ state and the recently discovered $Σ_{b} (6097)$ . Assuming the equal spacing rule and to complete this multiplet, we predict the existence of a $J = 1/2$ $Ω_{b}$ odd parity state, with a mass of 6360 MeV and that should be seen in the $Ξ_{b} K ˉ$ channel.
↳ hep-phhep-exnucl-thEPJC(2020)·45 citations
07
Generalization of Bantilan-Ishi-Romatschke flow to Magnetohydrodynamics
M. Shokri🇮🇷
We present a generalization of the Bantilan-Ishi-Romatschke (BIR) solution of relativistic hydrodynamics to relativistic magnetohydrodynamics (RMHD). Using the symmetries of the boundary of the Kerr-AdS5 black hole, and certain simplifying assumptions we solve the equations of RMHD on this boundary for a highly conductive fluid. We then transform the resulting solution to the flat spacetime. Furthermore, we show that the force-free condition causes the magnetic field to become singular at particular points and propose a regularization process for removing the singularities. The regularization process reveals the importance of non-vanishing electrical current in RMHD.
↳ hep-thgr-qchep-phnucl-th+1JHEP(2020)·8 citations
08
Current-driven tricritical point in large- $N_{c}$ gauge theory
Takuya Imaizumi🇯🇵 · Masataka Matsumoto🇯🇵 · Shin Nakamura🇯🇵
We discover a new tricritical point realized only in non-equilibrium steady states, using the AdS/CFT correspondence. Our system is a (3+1)-dimensional strongly-coupled large- $N_{c}$ gauge theory. The tricritical point is associated with a chiral symmetry breaking under the presence of an electric current and a magnetic field. The critical exponents agree with those of the Landau theory of equilibrium phase transitions. This suggests that the presence of a Landau-like phenomenological theory behind our non-equilibrium phase transitions.
↳ hep-thcond-mat.stat-mechcond-mat.str-elnucl-thPRL(2020)·11 citations

Affiliations

first authorsco-authorsvia INSPIRE