Nuclear Theory·nucl-th

Thursday·April 30, 2015

8 papers—4 primary·4 cross-listed

01
Particle-hole nature of the light high-spin toroidal isomers
A. Staszczak · Cheuk-Yin Wong
Nuclei under non-collective rotation with a large angular momentum above some threshold can assume a toroidal shape. In our previous work, we showed by using cranked Skyrme-Hartree-Fock approach that even-even, N=Z, high-K, toroidal isomeric states may have general occurrences for light nuclei with 28<=A<=52. We present here some additional results and systematics on the particle-hole nature of these high-spin toroidal isomers.
nucl-thActa Phys.Polon.B(2015)·10 citations
02
Shape transition in the even-even Cerium isotopes
B. Mohammed-Azizi · A. Helmaoui · D. E. Medjadi
The deformation energy of the even-even nuclei of the Cerium isotopic chain is investigated by means of the Macroscopic-Microscopic method with a semi-classical shell correction. We consider axially symmetric shapes. Binding energy and two neutron separation energy are also evaluated. For the sake of clarity several important details of the calculations are also given. It turns out that all these nuclei have prolate equilibrium shape. The regions of maximum deformation are obtained around N=64 and N=102. There is no critical-point of quantum phase transition in this isotopic chain.
nucl-thProgress in Physics, vol. 11 (2015), issu…·0 citations
03
Resonant states of neutron-rich $Λ$ hypernucleus $_{Λ}^{7}$ He
E. Hiyama🇯🇵 · M. Isaka🇯🇵 · M. Kamimura🇯🇵 · T. Myo🇯🇵 · T. Motoba🇯🇵
The structure of neutron-rich $Λ$ hypernucleus, $_{Λ}^{7}$ He is studied within the framework of an $α + Λ + n + n$ four-body cluster model. We predict second $3/ 2^{+}$ and $5/ 2^{+}$ states, corresponding to a $0 s$ $Λ$ coupled to the second $2^{+}$ state of $^{6}$ He, as narrow resonant states with widths $Γ \sim 1$ MeV to be at 0.03 MeV and 0.07 MeV respect to the $α + Λ + n + n$ threshold. From an estimation of the differential cross section for the $^{7} Li (γ, K^{+})_{Λ}^{7}$ He reaction, there is a possibility to observe these state at JLab in the future. We also calculate the second $2^{+}$ state of $^{6}$ He as resonant state within the framework of an $α + n + n$ three-body cluster model. Our result is $2.81$ MeV with $Γ =$ 4.63 MeV with respect to the $α + n + n$ threshold. This energy position is $\sim 1$ MeV higher, and with a much broader decay width, than the recent SPIRAL data. It is suggested that an experiment at JLab to search for the second $3/ 2^{+}$ and $5/ 2^{+}$ states of $_{Λ}^{7}$ He would provide an opportunity to confirm the second $2^{+}$ state of the core nucleus $^{6}$ He.
nucl-thPRC(2015)·29 citations
04
Low-energy theorems for nucleon-nucleon scattering at unphysical pion masses
V. Baru🇩🇪 · E. Epelbaum🇩🇪 · A. A. Filin🇩🇪 · J. Gegelia🇩🇪
The longest-range part of the nuclear force due to the one-pion exchange governs the energy dependence of the scattering amplitude in the near-threshold region and imposes correlations between the coefficients in the effective range expansion. These correlations may be regarded as low-energy theorems and are known to hold to a high accuracy in the neutron-proton 3S1 partial wave. We generalize the low-energy theorems to the case of unphysical pion masses and provide results for the correlations between the coefficients in the effective range expansion in this partial wave for pion masses up to Mpi ~ 400 MeV. We discuss the implications of our findings for the available and upcoming lattice-QCD simulations of two-nucleon observables.
nucl-thhep-lathep-phPRC(2015)·41 citations

Affiliations

first authorsco-authorsvia INSPIRE

Particle-hole nature of the light high-spin toroidal isomers

Shape transition in the even-even Cerium isotopes

Resonant states of neutron-rich Λ hypernucleus Λ7​He

Low-energy theorems for nucleon-nucleon scattering at unphysical pion masses

Affiliations

Resonant states of neutron-rich $Λ$ hypernucleus $_{Λ}^{7}$ He