Neutron-deficient superheavy nuclei obtained in the Pu240+Ca48 reaction

We present new results from investigations of the Pu-240 + Ca-48 reaction at a projectile energy of 250 MeV. Three new decay chains of (285)Fl were detected with decay properties mostly consistent with those measured in earlier studies. An additional chain was observed where the nuclei may decay through energy levels different from those of the other six chains registered so far. The cross section of the Pu-240((48C)a,3n)(285)Fl reaction was measured to be 0.58(-0.33)(+0.60) pb, which is a factor of about 4-5 lower than that measured in the previous experiment at 245 MeV beam energy [V.K. Utyonkov et al., Phys. Rev. C 92, 034609 (2015).], consistent with expectations. The origin of an additional chain consisting of a recoil, a particle, and fission event is analyzed. The assignment of 25 short-lived SF events observed in this experiment is also discussed.