Observation of a Rotational Band in the Odd-ZTransfermium NucleusMd101251

Abstract

A rotational band has been unambiguously observed in an odd-proton transfermium nucleus for the first time. An in-beam gamma-ray spectroscopic study of 101/251Md has been performed using the gamma-ray array JUROGAM combined with the gas-filled separator RITU and the focal plane device GREAT. The experimental results, compared to Hartree-Fock-Bogolyubov calculations, lead to the interpretation that the rotational band is built on the [521]1/2(-) Nilsson state.

Description of the asymmetric to symmetric fission transition in the neutron-deficient thorium isotopes: Role of the tensor force

“…This additional kinetic energy corresponding to a compact scission mode results in a drop of the TXE which leads to a loss of 1 neutron per fragment for scenario 1 and 3, and 2 neutrons per fragment for scenario 2. It is in agreement with the loss of 2 − 2.5 neutrons on the total multiplicity which has been measured by the SOFIA group [58,59].…”

“…This is an unusual short value for a symmetric scission, more characteristic of an asymmetric scission. As we will see later, this is a first theoretical hint of the existence of the compact fission mode that could be correlated with the observations of the SOFIA experiment [58,59]. From Fig.…”

“…The study of the fission of the neutron-deficient Thorium isotopes, which are analyzed in this paper, has been motivated by the experimental data obtained during the 2012 SOFIA campaign at GSI Darmstadt [58,59]. The measurements concern the thorium isotopes 230 Th, 229 Th, 226 Th, 225 Th, 223 Th, 222 Th and 221 Th.…”

“…The tensor interaction rearranges the position of the single particle orbitals changing the shell effects responsible for many of the properties of the quantities relevant to fission. In fact, it could be the missing ingredient required to explain a symmetric bimodal fission mode recently found in some neutron-deficient thorium isotopes [56][57][58][59]. Recent experimental data provided by the experiments of the SOFIA collaboration have revealed the existence of such a symmetric bimodal mode, composed of the standard super-long mode and a new compact mode.…”

Properties of nuclei in the nobelium region studied within the covariant, Skyrme, and Gogny energy density functionals

“…[45]. With that, the proton pairing strength is significantly larger than that given by the standard value of V n = V p = −1250 MeV fm 3 used for heavy nuclei in previous publications [39,7,[40][41][42][43] (which all have been carried out using the Lipkin-Nogami (LN) scheme, though). These previous values were obtained by adjusting moments of inertia in rotational bands of heavy nuclei [45].…”