Fusion enhancement in the collisions with Ca44 beams and the production of neutron-deficient Lr245–250</mml:…

Within the framework of the isospin-dependent quantum molecular dynamics model and statistical evaporation model, the production of neutron-deficient ²⁴⁵⁻⁻²⁵⁰Lr isotopes is investigated. The fusion probability in the reaction ⁴⁴Ca+²⁰⁹Bi is larger than that with ⁴⁰Ca beam, especially at a lower incident energy and smaller impact parameter, which is attributed to a lower dynamical barrier in ⁴⁴Ca+²⁰⁹Bi. The neck between the projectile and target grows faster in the reaction with ⁴⁴Ca beam, and the $N/Z$ ratio in the neck is larger, resulting in a lower dynamical barrier. Based on the fusion reactions of 40,44Ca+²⁰⁹Bi and 46,48Ti+²⁰³Tl, we predicted six new Lr isotopes, ²⁴⁵⁻⁻²⁵⁰Lr, with the maximal evaporation residue cross sections of 3.5 fb, 69 pb, 0.2 nb, 0.4 nb, 1.7 nb, and 1.8 nb, respectively.