football goes across the goal line.

[l3will]

A scrimmage kick that is a scoring attempt stays alive after
crossing the goal line unless grounded, touched by K, or
after breaking the plane of R's goal line has apparently
failed.
4.2.2 d. 2. also look at the exception there...


A scrimmage kick also stays alive until a field goal is scored.



Thus the debate about blowing the whistle when the ball is kicked on a try.