dead to the world

dead to the world (asleep, sleeping; fast asleep; sleeping very deeply) — спать мертвым сном, крепко спать; спать без задних ног, спать как убитый

Examples:
... She's dead to the world and will hopefully stay that way for at least half an hour. If not, I recommend a hasty retreat. A crabby five year old is not a pleasant thing to have around.
... The kids were dead to the world, sprawled like rag dolls across their respective beds.
"Is Bruce up yet?" "I doubt it — he was dead to the world ten minutes ago."

Related vocabulary:
[спать как убитый]
2.
dead to the world (as if dead; unconscious)
находящийся без сознания
не знающий о внешнем мире
3
dead to the world (intoxicated) — мертвецки пьяный; в отключке, в отрубе

Examples from thefreedictionary.com:
Six beers and he was dead to the world.
By midnight almost everybody at the party was dead to the world.