PHYSICS LETTERS B, vol.649, pp.394-399, 2007 (Journal Indexed in SCI)
One-parameter exactly separable versions of the X(5) and X(5)-beta(2) models, labelled as ES-X(5) and ES-X(5)-beta(2) respectively, are derived by using in the Bohr Hamiltonian potentials of the form u(beta) + u(gamma)/beta(2). Unlike X(5), in these models the beta(1) and gamma(1) bands are treated on equal footing. Spacings within the gamma(1) band are well reproduced by both models, while spacings within the beta(1) band are well reproduced only by ES-X(5) -beta(2) for which several nuclei with R-4/2 = E(4(1)(+))/E(2(1)(+)) ratios and [normalized to E(2(1)(+))] beta(1) and gamma(1) bandheads corresponding to the model predictions have been found. (c) 2007 Elsevier B.V. All rights reserved.