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(dnd 5e) Prove me wrong, RAW
(sh.itjust.works)
Disclaimer: this is purposefully obtuse.
Other effects in the game which explicitly state they kill you:
Shadows, succubi, massive damage, death saving throws, beholder death ray (notably not even their disintegration ray kills you), power word kill, vampires, mind flayers, night hags, drow inquisitors.
Clearly, if they intended for disintegration to kill you, they'd have said so. Since specific overrides general, and there is no general rule that disintegrated creatures are dead, I rest my case. QED.
*ahem Subtle Spell has entered the chat. Cast any spell that doesn't require a line of sight target and that doesn't require material components or otherwise rely on an "attack" or similar action. Like say Guardian Of Nature. Or, if you want to get REALLY pedantic: Dimension Door.