β-delayed proton decay of the proton drip-line nucleus 142Ho in the rare-earth region

New β-delayed proton precursorHo was produced via heavy ion induced reactionCd(Ca,p3n),and identified for the first time by using a He-jet fast tape transport system incombination with"p-γ"coincidence measurements.The β-delayed proton decay ofHo was ob-served and its half life was determined to be（0.44±0.1）s.By fitting the experimental relativebranching ratios to final states in the proton daughter nucleusTb and the energy spectrum ofβ-delayed protons with a statistical model calculation,the ground-state spin ofHo was assignedas 5,6 or 7.Nuclear energy-potential-surface（EPS）calculations were performed using theWoods-Saxon Strutinsky method.The calculated results favored the assignments of 7toHo.ASthe by-products,some γ-transitions in the proton daughter nuclei following the β-delayed protondecays of precursorsGd,Tb,Tb,andDy were reported here for the first time.