Correlations between the alpha particles and ejectiles in the 208 MeVN14onNb93reaction at three different ejectile angles

The in plane correlations between alpha particles and various ejectiles were investigated in the reaction of 208 MeV ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ on ${}_{}{}^{93}{}_{}{}^{}\mathrm{Nb}$ at ${\theta }_{\mathrm{HI}}=+22\mathrm{}°, +50\mathrm{}°, \mathrm{and} +80\mathrm{}°$. There were three sources of coincident alpha particles: (i) the sequential alpha decay of the excited ejectiles, (ii) the equilibrium alpha emission from the targetlike fragments, and (iii) the nonequilibrium process. Process (i) contributed mainly to the cross sections with the angular range of ${\theta }_{\alpha }$ close to ${\theta }_{\mathrm{HI}}$. Process (ii) contributed to the lowest part of the alpha energy spectra irrespectively of ${\theta }_{\mathrm{HI}}$ and ${\theta }_{\alpha }$. The remaining part was ascribed to process (iii). For this process the differential coincidence cross section of the lower energy part of the alpha particles was approximately factorized as $\frac{d^4\sigma }{d{\Omega }_{\mathrm{HI}}d{\Omega }_{\alpha }d{E}_{\mathrm{HI}}d{E}_{\alpha }}=K{\left(\frac{d^2\sigma }{d{\Omega }_{\mathrm{HI}}d{E}_{\mathrm{HI}}}\right)}_{\mathrm{singles}}{\left(\frac{d^2\sigma }{d{\Omega }_{\alpha }d{E}_{\alpha }}\right)}_{\mathrm{singles}}$ with $K\sim 0.4/\mathrm{b}$, whereas the higher energy part of the alpha particles emitted at the forward angles had a tendency to coincide weakly with the ejectiles emitted at the backward angles (${\theta }_{\mathrm{HI}}=+50\mathrm{}° \mathrm{and} +80\mathrm{}°$) as compared to the lower energy part of the alpha particles.