R 5-1-1

A series of 4 consecutive scrimmage downs shall be awarded to the team that is next to put the ball in play by a snap at the beginning of each half and after a score (including try), safety, touchback or change of team possession. [S8] A new series shall be awarded to the offense if:
a. It is in legal possession (following the application of any accepted live ball penalty) of the ball beyond the middle when the ball is declared dead and it is the first time in this series that has happened. If a subsequent play or penalty brings the ball back behind the middle and the ball is then advanced across the middle line for a second time during the same series, no new first down shall be awarded. AR 5-1-1-I to II
b. An accepted penalty results in or mandates a first down.
A new series shall be awarded to the defense on its own 5-yard line if the offense following 4th down has failed to score or earn a new first down.
A new series shall be awarded to the defense at the dead ball spot after an interception.