Umpires :

The game on the field is regulated by two umpires.One of who stands behind the wicket at the bowler's end, the other in a position called "square leg". The main role of the umpires is to adjudicate on whether a ball is correctly bowled  when a run is scored, and whether a batsman is out but the fielding side must appeal the umpire for the decision. Umpires also determine when intervals start and end, decide on the suitability of the playing conditions and can interrupt or even abandon the match due to circumstances likely to endanger the players, such as a damp pitch or deterioration of the light.Without the umpires the cricket is impossible to play cause the players cannot decide abut the no balls and wide balls etc. The umpires also examine about the lights which are used in the game. If the lights are getting dimmer then the umpires stops the game. Some decisions cannot be handled by the umpires on the ground. Since the decision must be accurate and must be fair so there is third umpire also who sits in a room and gives the decision looking at the video of the game whenever the umpires ask his decision. 

The umpires are also responsible to maintain discipline in the field. Sometimes on high intensity game players can cross the discipline so it is the duty of the umpire to assure that the game is played in friendly environment and the umpires are allowed to fine the players for any in-disciplinary act.

Scores:

The match details, including runs and dismissals, are recorded by two official scorers one representing each team. The scorers are directed by the hand signals of an umpire. For example, the umpire raises a forefinger to signal that the batsman is out  he raises both arms above his head if the batsman has hit the ball for six runs. The scorers are required by the Laws to record all runs scored, wickets taken and overs bowled; in practice, they also note significant amounts of additional data relating to the game.