ΛΛ pairing in multistrange hypernuclei

Abstract

Multi-strange Ca, Sn and Pb hypernuclei with ΛΛ pairing interaction are investigated within the Hartree-Fock-Bogoliubov approach. The unknown ΛΛ pairing strength is calibrated to match with the maximal value for the prediction of the Λ pairing gap in uniform matter for densities and isospin asymmetries equivalent to those existing in multi-Λ hypernuclei. In this way, we provide an upper bound for the prediction of the Λ pairing gap and its effects in hypernuclei. The condensation energy is predicted to be about 3 MeV as a maximum value, yielding small corrections on density distributions and shell structure. In addition, conditions on both Fermi energies and orbital angular momenta are expected to quench the nucleon-Λ pairing for most of hypernuclei.

Neutron-star tidal deformability and equation-of-state constraints

“…Finally, astronomical observations and terrestrial experiments can be translated to microscopic constraints through the symmetry energy [265], the energy budget for increasing asymmetry between neutrons and protons. Various studies have empirically identified correlations between various combinations of parameters that characterize the symmetry energy and its density dependence with the neutron star radius and tidal parameters [246,[266][267][268][269] or terrestrial experimental results [239,[270][271][272], as they all are linked to the low-density behavior of the equation of state around (twice) saturation. The tidal constraints from GW170817, and more recently radius constraints from NICER have been used to examine implications for the symmetry energy [273][274][275][276][277][278][279][280][281][282] as well as potential systematics in the mapping [283].…”

Ground State Properties of Charmed Hypernuclei with Mean Field Approach

“…The density functional, deduced from the G-matrix calculation in uniform matter, will be generically named as DF-NSC89, DF-NSC97a and DF-NSC97f, hereafter, see Ref. [31] for more details. The oldest DF-NSC89 functional can reproduce with a good accuracy the experimental single particle energies of Λ hyperon for light hypernuclei such as 5 Λ He or 13 Λ C, but for the heavier hypernuclei like 41 Λ Ca or 209 Λ Pb, DF-NSC97a and DF-NSC97f give results close to the experimental data [30,32].…”

Strength of pairing interaction for hyperons in multistrangeness hypernuclei

“…So far there is only one confirmed double-Λ hypernucleus 6 ΛΛ He [10] and two candidates 13 ΛΛ B [11] and 10 ΛΛ Be [12]. Nevertheless, many theoretical efforts have been devoted to investigating the structure of more double-Λ and even multistrangeness (−S ≥ 3) hypernuclei [13][14][15][16][17][18][19][20].…”

“…Since the pairing strength for Λs has been taken as 4/9 of that for nucleons, it is not unexpected that the pairing effects of Λs are weaker compared to nucleons. [19] with SLy5 for the NN interaction and DF-NSC89, DF-NSC97a and DF-NSC97f for the ΛN interaction in the ph channel. In the MDC-RHB calculations, the effective interactions PK1-Y1 and NLSH-A are used for the ph channel and the separable pairing force of finite range with the pairing strength G Λ = 4/9 • G N = 323.56 MeV•fm 3 is used for pp channel.…”

“…There have not been much work on the pairing effects of hyperons in finite nuclei, though some efforts were made to the study of double-Λ and multistrangeness (−S ≥ 3) hypernuclei [13][14][15][16][17][18][19][20]. In Ref.…”