Liberals, a la New Right, plan attack on 4 senators

A liberal political group is adopting New Right political tactics by attacking four conservative senators with the same kind of controversial negative advertising campaign used to help defeat liberal Democrats.

The Progressive Political Action Committee, or ProPAC, is taking aim at Sens. Orrin G. Hatch of Utah, S. I. Hayakawa of California, Harrison H. Schmitt of New Mexico, and Jesse A. Helms of North Carolina.

ProPAC says it will begin an advertising campaign against the four next month. It is launching a direct-mail fund-raising drive.

Messrs. Hatch, Hayakawa, and Schmitt are up for reelection next year and Mr. Helms, in 1986