Quenching of transition results from 2p-1h doorway mechanism by p-wave neutron excitation * * Supported by the National Natural Science Foundation of China (10175091, 11305007) and the National Research Foundation of Korea (2018R1A6A06024970)

Abstract

The ratio of transition-intensities from the initial capture state to low-lying states may represent the model-independent -strength function, which reflects the effects of different neutron-capture reaction mechanisms. The extraordinary quenching of the transition from the p-wave neutron radiative capture in Fe is observed, for the first time, from the pronounced enhancement of the -strength function ratios and . The 2p-1h doorway excitation leads to suppression of the transition to the ground state and the enhancement of the and transitions to the first and second excited states, respectively. The sub-shells supply the exact number of spaces required for the 2p-1h configuration, which features the neutron capture mechanism in the vicinity of A= 55.