Question

can Barium undergoe beta decay as it is stable?

Answer 1

if yes to what

Answer 2

which isotope of barium are you talking about

Answer 3

There are several isotopes of barium, and some of them do undergo beta decay. They are so rare, however, that their percentages are practically 0. See link for table of nuclear data on barium. http://hyperphysics.phy-astr.gsu.edu/hbase/pertab/ba.html#c3