of coarse, iffen yore a writer, yew probably pick up a dictionary for aide with words
https://www.merriam-webster.com/dictionary/decaylook up a definition two use
"2 : to decrease usually gradually in size, quantity, activity, or force"
n may bee an example too help yore understanding
"In the upside-down world of quantum theory, for instance, a radioactive particle decays and doesn’t decay during any given period of time — and each result plays out in a separate universe.
—
Dan Falk /, NBC News, "What is the multiverse?," 22 May 2018"