The regents of the Smithsonian institution are negotiation with Phillip Samuel Hughes, a retired assistant comptroller general of the United States, to conduct "a scholarly, constitutional study" of the Smithsonian's relationship to the federal government.

Charles Blitzer, assistant secretary for history and art for the Smithsonian, who briefed reporters yesterday after a regents meeting, said Hughes was selected to carry out the study by Sen. Henry M. Jackson (D-Wash.), who heads a regents committee recently recreated to review criticisms of the Smithsonian's financial practices by the General Accounting Office, members of Congress and the press.

Blitzer said the regents generally approved Jackson's selection of Hughes and authorized the senator to proceed with negotiations aimed at outlining the scope of the study and Hughes' direction of it. Blitzer said Hughes met with the regents at their meeting yesterday and indicated that the could begin his work in July if he is formally commissioned.

Blitzer said the regents' study will attempt not to duplicate a recent GAO audit of the Smithsonian's fiances - an audit that has been roundly criticized as inadequate by members of Congress - or a possible upcomin ginvestigation of the Smithsonian's finances by House Appropriations Committee investigators.

The appropriations committee investigation was requested this week by the House Appropriations Subcommittee of the Department of the Interior and Related Agencies, which handles the Smithsonian's budget. Appropriations Committee Chairman George H. Mahon (D-Tex.), himself a Smithsonian regent, must approve the request before the investigation can begin.

At their meeting yesterday the regents put off a decision on whether future meetings should be open to the public and deferred another decision on whether the Museum of African Art on Capitol Hill should become a part of the Smithsonian, Blitzer said.