Paul P. Sedgwick, a student at the Massachusetts Institute of Technology, was sentenced to six months in jail and fined $100 in Cambridge District Court yesterday when he was convicted of assaulting a Harvard policeman and of disorderly conduct.

Sedgwick was arrested August 29 after Harvard and Cambridge police broke up an SDS-sponsored Radical Arts Troupe (RAT) play in Forbes Plaza. Police had earlier ordered the group from the Yard. Sedgwick was charged with assaulting Harvard Officer William Head.

Sedgwick appealed the conviction, and Cambridge District Court Judge M. Edward Viola set bail at $100.

Acting as his own attorney, Sedgwick charged that he was victimized by police brutality. Nine defense witnesses denied police allegations that Sedgwick struck Head in the chest and shins after assaulting him from behind.

Inadmissable

Judge Viola ruled as inadmissible evidence a doctor's affidavit stating that Sedgwick's eardrum had been punctured during the fracas that followed his arrest. After several outbursts of laughter, Viola ruled that the affidavit could not be used because the doctor was not present to be cross-examined.

Harvard and Cambridge police officials stated that they dispersed the RAT group because the play's audience was blocking the sidewalk near Harvard Yard and later at Forbes Plaza.

Sedgwick's trial came just one week after the conviction of former Harvard student Cheyney Ryan before the same judge on charges of trespassing during SDS demonstrations at Harvard last May.