New enhanced tunneling in nuclear processes

The small sub-barrier tunneling probability of nuclear processes can be dramatically enhanced by collision with incident charged particles. Semiclassical methods of theory of complex trajectories have been applied to nuclear tunneling, and conditions for the effects have been obtained. We demonstrate the enhancement of $\alpha$ particle decay by incident proton with energy of about $0.25\text{MeV}$. We show that the general features of this process are common for other sub-barrier nuclear processes and can be applied to nuclear fission.

Figure 1

The right side of the energy dependence (smooth enhancement) of the tunneling probability corresponds to the domain $\epsilon >1.85\text{MeV}$ and is related to positive assistance of tunneling. The Euclidean resonance occurs at $\epsilon =0.25\text{MeV}$ at the region of negative assistance tunneling $\epsilon <1.85\text{MeV}$.

Figure 2

(a) The trajectory of the $\alpha$ particle; (b) The trajectory of the proton. These classical trajectories in imaginary time are only a convenient way to describe the effect. In real time the proton does not approach the nucleus and interacts with it solely via the Coulomb field.