Effects of finite temperature and pairing correlations in multi- Λ hypernuclei

The influence of finite temperatures and pairing correlations on the ground-state properties of multi-Λ Ca, Sn, and Pb hypernuclei is explored using the finite-temperature Hartree-Fock-Bogoliubov approach and contact pairing interaction. A critical temperature is predicted and is in agreement with the Bardeen-Cooper-Schrieffer relationship kBTC^Λ≈0.5Δ_ΛT=0, beyond which pairing correlations drop to zero. Particle densities, Λ single-particle energies, and nuclear radii are weakly impacted by pairing as well as by finite temperatures. However, other nuclear properties which are more sensitive to pairing correlations, such as Λ-pairing gaps, condensation energies, and abnormal densities are also more impacted by finite temperature, especially around the critical temperature. Furthermore, calculations show the occurrence of the pairing re-entrance effect in the _70Λ²⁸⁰Pb hyperon drip-line hypernucleus. Our study provides insight into the thermal evolution of Λ pairing, i.e., the emergence and vanishing of pairing correlations in multi-Λ hypernuclei as a function of temperature.