SACRAMENTO — A state judicial commission on Monday declined to punish Aaron Persky, the Santa Clara County Superior Court judge who was widely criticized for the six-month jail sentence he imposed on a former Stanford University student accused of sexually assaulting an unconscious woman.

The state Commission on Judicial Performance, in a rare 12-page explanation of its decision to close its investigation, acknowledged receiving “thousands of complaints and petitions” targeting Persky but said it found no proof of misconduct that would warrant any admonishment or other form of discipline.