A Collective Rotational State of Spherical Nuclei

Abstract

We consider a particular many-body rotational excitation 'P of a spherical self-bound system of particles, of the form studied by Lekner (1974). This angular momentum eigenstate is translationally invariant and thus is not a spurious state. The energy of 'P is found from first principles to be substantially larger than that of the first 2+ excited states of even-even nuclei, with the exception of 208Pb. The quadrupole moment is negative, the g-factor is approximately Z/A and the lifetime is shorter than the single-particle (Weisskopf) value by a factor of the order of A/Z2. It is suggested that these states are the finite system rotational analogues of Feynman's phonons and rotons.