California slid in under the wire yesterday in the competition for the government's proposed superconducting supercollider, even though its legislature has refused to authorize $560 million in incentives to attract the $6 billion atom smasher.

"We're in," said University of California spokesman Paul Sweet, striding across L'Enfant Plaza to deliver the state's formal proposal to Energy Department officials minutes before the department's 2 p.m. deadline.

California was the last entry in what has developed into a frenetic national sweepstakes with one grand prize: a 53-mile-long tunnel, billed as the world's largest and most costly research tool, that is expected to bring thousands of jobs, millions of payroll dollars and a cascade of high-tech development to its eventual host.

At least 24 states are vying for the honor, some offering several sites for the Energy Department's perusal. Department officials will release a final list of candidates today.

The applications came by the tomes and the truckloads, some accompanied by governors and home-state news crews, and were loaded onto a truck outside Energy Department headquarters in what became a minor street show on Independence Avenue.

The drama award went to California, whose proposal was hung up for weeks by a partisan dispute over whether some contracts should be set aside for companies headed by minorities or women.

Earlier, the California Collider Commission said it would not submit a proposal without legislative authorization. But when it became clear yesterday that no authorization would be forthcoming before the application deadline, the commission convened an emergency meeting to reconsider its position.

As a precaution, the state had delivered most of its documentation Tuesday. But as the minutes ticked by yesterday, Sweet was still holding the official proposal, pacing the sidewalk in front of the Energy Department and conferring by mobile phone with University of California President David P. Gardner, chairman of the collider commission.

The word came with eight minutes to spare. "That's it. We're submitting," Sweet said. He handed the box to Energy Department procurement chief Bert Roth, who signed the receipt with a flourish.

The California proposal is contingent on legislative approval of the multimillion-dollar incentive package, which would be used to purchase land at either of its two proposed sites and provide improved roads, sewers and other "environmental enhancements."

But Sweet said he did not believe the uncertainty would hamper California's candidacy. "We don't believe it puts us at any disadvantage, based on the rules as we know them," he said.

Energy Department officials will check the bids for completeness and send them to the National Academy of Sciences, where a 20-member panel will review them for technical merit and winnow them to a "best-qualified list."

That list will return to the Energy Department, which will pare it to a single "preferred" site. President Reagan will have the final say, however, and while the selection process is supposed to be nonpolitical, some contenders had fervently hoped California would not be in the running.

Because most, if not all, of the sites are expected to be found geologically suitable for the supercollider, where scientists will study the collision of accelerated beams of particles, the final selection is likely to be influenced by more subjective criteria, such as schools, cultural attractions, climate and attractiveness of life style.

Both California sites, one near Davis and the other near Stockton, are conveniently close to the San Francisco Bay area.