Separation energies from a symmetry-based mass formula for non-strange nuclei and Λ hypernuclei

Complete text of publication follows. Recently we have proposed a nuclear binding energy formula for the unified description of normal nuclei and λ hypernuclei: B(N,Z,Λ) = avA - asA2/3 - ac Z2/A1/3 - aa (N-Z)2/A + ay S/Aγy + am [M]/Aγm. Fitting the binding energies of these two types of nuclei separately and jointly in various mass regions, we found that the (sixth) Majorana term successfully replaces the pairing term of Weizsaecker's mass formula, furthermore, this term, together with the (fifth) strangeness term describes the binding energies of λ hypernuclei, too. As a further step, we analyzed nuclear and λ separation energies for these nuclei. Below we show the results for neutron separation energies Sn = B(N,Z,0) - B(N - 1,Z,0) for normal nuclei. The theoretical plot was made using the parameter set obtained from a fit to nuclei with N, Z ≥ 2. The gaps in the experimental plot are due to shell effects, which are not accounted for by our formula. Work is in progress to incorporate these effects in our method. We also compared our formula with that of Dover and Gal, which is the only other similar mass formula known to us. (author)