March 6, 1984

Lebanon today formally canceled its troop withdrawal accord with Israel, declaring the American-sponsored agreement ''null and void.'' The Israeli Government, in a statement issued by Prime Minister Yitzhak Shamir's office, strongly condemned the Lebanese decision, describing it as ''a death sentence for Lebanese independence and sovereignty.'' The cancellation of the accord appeared to mark the end of the so-called ''Israeli era'' in Lebanese politics and to shift Lebanon solidly back into the Syrian-Arab fold. It signified a major victory for the Syrians and their Soviet backers, who have opposed the accord of last May 17 from the beginning because of the new relationship it would have established between Israel and Lebanon and because of the diplomatic achievement it signified for the United States.

Gary Hart's victory in the Maine caucuses Sunday propelled the Democratic Presidential campaign into an angry new phase yesterday. Walter F. Mondale acknowledged that he was fighting for his political survival and denounced Mr. Hart with the harshest personal attacks of the campaign year. Admitting that ''I got hurt bad'' by defeats in Maine and New Hampshire, Mr. Mondale for the first time centered his criticism on Mr. Hart's character and personality. In speeches in Boston, he depicted Mr. Hart as a coldly intellectual man who would bring an ''unfair, regressive approach'' to the problems of common people. Mr. Hart's strategists, convinced that the Mondale campaign was reeling, studied their private polls to see if the Senator from Colorado had a chance to deliver a decisive blow against former Vice President Mondale in the Southern primaries next Tuesday. A Hart adviser described the region as ''poised for movement'' against Mr. Mondale.

The National Can Corporation, the nation's third-largest metal can company, said yesterday that the investor Victor Posner, who now owns 37.2 percent of the company, had offered $40 a share for the rest of the shares, or a total of $410 million. A National Can spokesman said the company, which announced earlier that it was considering a leveraged buyout among other alternatives, is submitting the offer to its independent directors for evaluation. ''Right now, it appears to be a favorable opportunity,'' the spokesman said. She said the evaluation would take at least four months.

The Securities and Exchange Commission yesterday listed several prominent businessmen that it intends to call as witnesses in its case against Paul Thayer, the former Deputy Secretary of Defense. Mr. Thayer has been charged with helping eight individuals make $1.9 million by illegally providing them with insider information. The S.E.C., in a filing with the Federal District Court in Manhattan, also provided new details involving the commission's case. Included, for example, are names of the members of a backgammon group that the commission maintains traded information among themselves.. Among the 21 individuals the S.E.C. said it intends to call as witnesses are Harry J. Gray, chairman of the United Technologies Corporation; Thomas G. Pownall, chairman of the Martin Marietta Corporation; August Busch 3d, chairman of the Anheuser- Busch Companies; Jake Butcher, whose Tennessee banking empire collapsed last spring; Burt Lance, who was President Jimmy Carter's budget director, and Brynn Thayer, Mr. Thayer's daughter. None of these individuals has been charged by the Securities and Exchange Commission with violating any laws.

The nation's major automobile manufacturers reported today that sales rose 24.6 percent, on a daily rate basis, in late February. The companies, G.M., Ford, Chrysler, A.M.C., VW and Honda, sold a total of 248,062 units in the Feb. 21-29 period, which had eight selling days this year and seven last year. Sales for the entire month of February, with 25 selling days this year and 24 last year, were up 42.5 percent, to 655,016. The daily selling rate of 26,201 was the best daily rate for February since 1979. Last year the car makers sold 441,226 cars, or 18,384 a day, in the month.