Investigation of γ -ray fold distributions in N ≤ 82 Gd, Eu and Sm nuclei: Observation of a double-humped fold distribution

Cross-sections and γ -ray fold distributions have been measured for the 97 Mo+ 51 V, 100 Mo+ 48 Ti and 114 Cd+ 36 S reactions at energies of 238, 215 and 182 MeV of the 51 V, 48 Ti and 36 S projectiles, respectively. For the 97 Mo( 51 V, α 2 n 142 Eu reaction channel a double-humped fold distribution has been observed. This fold distribution can only be understand if an incomplete-fusion reaction mechanism associated with the α -particle emission is assumed. The 97 Mo( 51 V, α n 143 Eu reaction channel represents an incomplete-fusion reaction channel as well and its single-humped fold distribution can be described on the same footing as that of the α 2 n channel. The fold distributions associated with xn and pxn channels can be explained assuming complete-fusion reactions. For the calculations in terms of an incomplete-fusion reaction mechanism a narrow angular momentum window, ranging from ≈ 68 to 82ℏ has been assumed for the 97 Mo( 51 V, αn and α 2 n reaction channels. The complete-fusion reaction mechanism is considered to be negligible in this angular-momentum range.