The breaker to this circuit is now dead, in tripped position will not reset.
Of course, the bad breaker hypothesis is a good one. It's just that SqD, in my experience, has had such extraordinary quality, I would try to rule out any other possiblity.
I tout Square "D" to my customers as the "Cadillac" of breakers,...well,at least the QO style anyway,...
At least the breaker failed in the "open circuit" condition. A safe failure. Not like FPE breakers that are known to fail in the "on" position and become stuck on passing large quantities of fault current.....
