USC has to go 2-2 in its remaining games against ASU, UA, Colorado, and UCLA. Utah has to win out. Yes, Utah is mathmatically still alive. But odds of winning the south are less than 10% at this point.
There are more complicated scenarios where Utah could win a tie breaker with 3 losses, but those require two USC losses, only one Utah loss, and then winning a 3 or 4 way tie breaker. LONG SHOT.