Laser-induced neutron radiative capture reaction

Laser-stimulated enhancement of the p-wave radiative capture of a low-energy neutron is investigated. Conceptually, this process proceeds as follows: in the presence of a strong laser field, the capture of a low-energy neutron and a simultaneous low-energy photon transition may populate a p-wave resonance near the binding energy; this will result in an enhanced E1 radiative transition to a low-lying s-wave neutron bound state. The cross section for such a process is expressed in terms of the intensity of the laser radiation and nuclear matrix elements. Numerical estimates show that an appreciable enhancement of the radiative capture will not be observed until the laser electric field strength exceeds a magnitude of 105 to 108 V/cm. The lower value corresponds to the existence of a p-wave resonance in the intermediate state and an s-wave resonance in the entrance channel, whereas the higher value corresponds to the case when the s-wave resonance is absent. They are also much higher than an estimate reported recently in the literature; an explanation is given for possible sources of discrepancy.