Harvard Scientist Locates Sixth Quark

A team of scientists in Geneva, headed by Professor of Physics Carlo Rubbia, has found evidence of a sixth kind of quark, one of the most sought after discoveries in modern physics.

Physicists who study particles of matter smaller than atoms have predicted that six quarks would ultimately be found If Rubbia's findings are confirmed, it would complete the roster.

Quarks are believed to be the basic building blocks of all the larger atomic particles. Three of them are bound together to form each proton and neutron in the nuclei of atoms.

The discovery, however, was not totally unexpected. "It just didn't pop out of the garden," said Rubbia, who was contacted in Geneva earlier this week.

Based on the symmetry often found in nature, the discovery was expected, said Val Fitch of Princeton University, a prominent high energy physicist.

The tests--conducted at the European Laboratory for Particle Physics, where Rubbia is researching for the summer--consist of aiming a beam of protons accelerated to an energy of 270 billion volts around a four-mile ring and into beam of anti-protons flying in the opposite direction with the same energy.

The collisions generated a 540 billion electron volt of energy, called a fireball, that materialized into showers of particles.

Rubbia developed this particular proton collision method and has been working with it since the late 1970s.

The quark's mass appears to he somewhere between 30 and 60 electron volts. The masses of atomic particles are given in energy equivalents.

Because quarks cannot normally be pried apart for direct observation, the production of the sixth quark required high energy, collisions barely within the reach of the machine in Switzerland.

After improvements to the performance of the accelerator, a new, 15-month series of tests are scheduled to begin this fall, which Rubbia said he expects will lead to further support of the quark finding.

Scientists at Harvard and at other universities in the United States said that the discov- ery will have major implications, but added that it was expected.

"Actually, it would have been more interesting if they didn't find it. It would have blown their minds," said Baird Professor of Science Francis M. Pipkin.

He analyzed the find by saying. "It's like it you know a guy and you know he's married, but you've never seen his wife."

If the presence of the quark could not be confirmed, the most popular theories in modern physics would "have had to be redone," said Chairman of Physics Department Richard Wilson.

According to Rubbia, the project was initially snubbed by government officials as well as Harvard scientists as improbable and faced great difficulty acquiring research funding.

"It was considered one of those crazy ideas," he said, adding that he had to conduct his research "freelance."

But, he said, Dean of the Faculty Henry Rosovsky, was one of the few who supported his work by allowing him use of the dean's discretionary funds.

"Now Harvard understands it was a good project to carry out," he added