Article révisé par les pairs
Résumé : The shell structure of superheavy nuclei is investigated within various parametrizations of relativistic and nonrelativistic nuclear mean-field models. The heaviest known even-even nucleus 264 156Hs108 is used as a benchmark to estimate the predictive value of the models. From that starting point, doubly magic spherical nuclei are searched in the region Z = 110-140 and N = 134-298. They are found at (Z = 114, N = 184), (Z = 120, N = 172), or at (Z = 126 , N = 184), depending on the parametrization.