Reinvestigation of U-222 in high-precision digital & alpha;-decay spectroscopy: Solution to the reduced decay-width anomaly

The & alpha; decay of 222U was reinvestigated using a general least-square superpulse fitting algorithm dedicated to resolving pileup signals in the decay of very short-lived nuclei. The & alpha;-particle energy of 222U was revised to be 9246(8) keV, and the precision was improved significantly compared with previous result. Using the present & alpha; energy, the anomaly in the systematics of the & alpha;-decay reduced width 82 observed at 222U in the NpNn scheme is solved, all the 82 values converge into a smooth and narrow band with NpNn up to & AP;90 in the northeast of 208Pb.