Waiting for God particle

Monday , July 2 , 2012

Wednesday wait for word on God particle

– Scientists sleepless as revelation day on family named after Bose draws near

New Delhi, July 1: Physicist Vivek Sharma hasn’t had much sleep over the past week because of a mix of work and excitement as he and his colleagues prepared to announce the latest results of the world’s longest and most challenging search for a subatomic particle.

The scientists, working in a research centre near Geneva, Switzerland, will at 9am local time on Wednesday issue what is expected to be a historic “update” on their search for the Higgs boson, at times called the “God particle”.

The Higgs boson is the last missing ingredient of an elegant theory of physics called the Standard Model that explains all the subatomic particles and forces in nature except gravity.

It belongs to a family of particles named after the 20th-century Indian physicist Satyendra Nath Bose, and was predicted to exist by British physicist Peter Higgs 48 years ago, but it has not been observed in earlier search efforts.

Two Higgs search teams at the European Organisation for Nuclear Research, or CERN, near Geneva had announced in December 2011 that they had observed some “tantalising hints” of the boson in the debris of proton-proton collisions in their laboratory.

Physicists consider the July 4 announcement far more significant because their data have since doubled. Over the past week, CERN scientists have been examining data in excruciating detail and preparing for presentations and public statements for the world.

“We’re cross-checking and digesting the results,” said Sharma, an India-born physicist at the University of California, San Diego, who is involved in the search for the Higgs boson at CMS, one of the two Higgs search experiments at CERN.

“We’re now discussing how to present what we’ve learned in an accurate way,” Sharma told The Telegraph tonight over the phone from Geneva.

In 2011, CERN teams had examined data corresponding to over 400 trillion proton-proton collisions in their giant subatomic particle accelerator, called the Large Hadron Collider. Since December, the reservoir of data analysed has doubled to more than 800 trillion collisions.

The doubled data allow scientists to examine the nature of the tantalising signals they had reported in 2011 with much better statistical precision. In December 2011, the scientists had reported signals suggesting a Higgs boson, about 125 times the mass of a proton.

“If the (signal) that we had observed in 2011 was because of the Higgs boson, then we now expect to be much more confident — the chance of making a mistake would be reduced to roughly 3 in 100,000,” Sharma said.

But Sharma and other senior team members say the world will need to wait until July 4 to learn about their findings — blogs, silent whispers in physics circles, and speculation about what will be announced that day notwithstanding.

“All I can say at this moment is that we have very good results — and very high quality data,” Aleandro Nisati, an Italian physicist involved in the search for the Higgs boson at CERN through a detector called Atlas, told this newspaper.

Physicists believe the July 4 report could contain one of three possibilities — stronger evidence for the Higgs boson, supporting the December results; dismissal of the signals reported in December as mere statistical fluctuations; or something else that is unexpected.

The Higgs boson is the key component of the Standard Model that helps explain how or why subatomic particles have mass. Physicists say that were it not for the Higgs boson, the universe could not have the structure and form it has today.

A Reuters report from Geneva today quoted a US physicist, Matt Strassler, as saying that without the Higgs boson, “nothing like human beings, or the earth we live on, could exist”.

“If this missing piece is not found, we’ll have to rewrite physics textbooks,” said Satyaki Bhattacharya, a physicist at the Saha Institute of Nuclear Physics, Calcutta. “But if it is found, there’s still lots of work ahead.”

The theory that predicts the Higgs boson also predicted two other subatomic particles — the W and Z bosons. “They were first observed in CERN in the 1980s but were studied to understand their properties and behaviour for years and years,” Bhattacharya said.

Whatever the CERN teams announce on Wednesday, physicists say the experiments at the Large Hadron Collider to spot the Higgs boson will continue. The Higgs boson has a fleetingly short lifespan and decays into various other subatomic particles.

“Each such decay mode will need to be observed and measured to confirm that it occurs in exactly the same manner as predicted by theory,” said Sudeshna Banerjee, a physicist at the Tata Institute of Fundamental Research, Mumbai, who is involved in studies at the Large Hadron Collider to look for new physics beyond the Standard Model.

A sense that “something” has been seen, the Reuters report said, has been bolstered not only by the announcement of the CERN seminar and a live video feed to the Melbourne congress but by other linked events scheduled around the globe.

New York’s Columbia University said it was holding an early-hours pyjama party in the hope of seeing “sub-atomic fireworks”.

In London, a concert hall across the Houses of Parliament has been booked for a similar daytime event.

Chinese, Japanese and Russian scientists will also be watching the seminar — as will scientists across several Indian laboratories, including the Saha Institute of Nuclear Physics.

The US Fermilab, where scientists have spent three decades looking for the Higgs boson using a collider named the Tevatron — shut down since last December as Washington cut off funds — has announced a seminar tomorrow.

Fermilab scientists plan to deliver their final Higgs search results tomorrow. Physicists have often said that to claim a discovery of a new particle, they have to be sure that there is less than one in a million chance that it is a statistical fluctuation.



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