‘Tantalizing Hints’ but No Direct Proof in Particle Search

December 13, 2011
‘Tantalizing Hints’ but No Direct Proof in Particle Search
By DENNIS OVERBYE - New York Times

Physicists will have to keep holding their breath a little while longer.

Two teams of scientists sifting debris from high-energy proton collisions in the Large Hadron Collider at CERN, the European Center for Nuclear Research, said Tuesday that they had recorded “tantalizing hints” — but only hints — of a long-sought subatomic particle known as the Higgs boson, whose existence is a key to explaining why there is mass in the universe. It is likely to be another year, however, before they have enough data to say whether the elusive particle really exists, the scientists said.

The putative particle weighs in at about 125 billion electron volts, about 125 times heavier than a proton and 500,000 times heavier than an electron, according to one team of 3,000 physicists, known as Atlas, for the name of their particle detector. The other equally large team, known as C.M.S. — for their detector, the Compact Muon Solenoid — found bumps in their data corresponding to a mass of about 126 billion electron volts.

If the particle does exist at all, it must lie within the range of 115 to 127 billion electron volts, according to the combined measurements. “We cannot conclude anything at this stage,” said Fabiola Gianotti, the Atlas spokeswoman, adding, “Given the outstanding performance of the L.H.C. this year, we will not need to wait long for enough data and can look forward to resolving this puzzle in 2012.”

Over the last 20 years, suspicious bumps that might have been the Higgs have come and gone, and scientists cautioned that the same thing could happen again, but the fact that two rival teams using two different mammoth particle detectors had recorded similar results was considered to be good news. Physicists expect to have enough data to make the final call by the summer.

The Atlas result has a chance of less than one part in 5,000 of being due to a lucky background noise, which is impressive but far short of the standard for a “discovery,” which requires one in 3.5 million odds of being a random fluctuation. Showing off one striking bump in the data, Ms. Gianotti said, “If we are just being lucky, it will take a lot of data to kill it.”

Physicists around the world, fueled by coffee, dreams and Internet rumors of a breakthrough, gathered in lounges and auditoriums to watch a Webcast of a series of talks and a discussion of the results at CERN, the European Center for Nuclear Research, Tuesday morning. The results were posted on the Web.

As seen on the Webcast, the auditorium at CERN was filled to standing room only. At New York University, dozens of physicists gathered in a physics lounge burst into applause.