Università degli Studi di Padova
  Dipartimento di Fisica "Galileo Galilei"

S E M I N A R I O

LUNEDI'  13  NOVEMBRE  2006, ALLE ORE 15:00
IN AULA S
DIPARTIMENTO DI FISICA, UNIVERSITÀ DI PADOVA
 
 

Prof. Roman N. SAGAIDAK

JINR, Dubna

terrà un seminario dal titolo:


"Fusion probability in reactions leading
to the heaviest nuclei
"


Abstract. Production of the heaviest nuclei in complete fusion reactions induced by heavy ions has been considered in a systematic way in the framework of the conventional barrier passing (fusion) model coupled with the standard statistical model. Available data on the excitation functions for fission and production of evaporation residues (ER) in very asymmetric combinations induced by 12C-22Ne on actinide target nuclei are described rather well with these models. The data allow one to adjust model parameters quite definitely. For reactions induced by 26Mg and heavier projectiles, when quasi-fission effects are starting to appear in the entrance channel of reactions, one had to introduce phenomenologically the quantity "fusion probability" Pfus to reproduce the ER excitation functions in the framework of the conventional "potential barrier - statistical model" approach. The exponential dependence of Pfus on the mean combined fissility was found in search for regularities in the behavior of the Pfus values extracted empirically from the data analysis. A scaling of the empirical fusion probabilities together with the adjusted parameters of the models allow one to predict cross section values for the unknown heaviest (superheavy) nuclei produced in various projectile-target combinations.

Fernando SCARLASSARA