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Updated: December 14, 2011 17:04 IST

Higgs boson ‘may have been glimpsed’

Ian Sample
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Professor Fabiola Gianotti briefs media about the Higgs Boson search during a press conference at CERN, in Geneva on Tuesday.
Professor Fabiola Gianotti briefs media about the Higgs Boson search during a press conference at CERN, in Geneva on Tuesday.

Confirmation may have to wait until the end of 2012 Scientists could have caught their first glimpse of the Higgs Boson, the curious particle thought to underpin the subatomic workings of nature.

Hundreds of physicists crowded into a seminar room at CERN, the European particle physics laboratory near Geneva on Tuesday, breaking into applause as Fabiola Gianotti and Guido Tonelli, who lead separate teams at CERN’s Large Hadron Collider (LHC), revealed evidence for the particle amid the debris of hundreds of trillions of proton collisions at the machine.

Thousands more tried to watch online although the live feed crashed shortly after the meeting started.

First postulated in the mid-1960s, the Higgs boson has become the most coveted prize in particle physics. Its discovery would rank among the most important scientific advances of the past 100 years and confirm how elementary particles acquire mass.

While the results are not conclusive -- the hints of the particle could fade when the LHC collects more data next year -- they are the strongest evidence so far that the Higgs particle is there to be found.

“We have narrowed down the region where the Higgs particle is most likely to be, and we see some interesting signals, but we need more data before we can reach any firm conclusions,” said Gianotti, who heads the team that works on the collider’s enormous Atlas detector. “It’s been a busy time, but a very exciting time.” Finding the Higgs boson has been a major goal for the GBP10bn LHC after a less powerful machine at CERN called LEP failed to find the missing particle before it closed for business in 2000. The hunt was joined by scientists at the Tevatron collider near Chicago, who will present their own results early next year.

The Higgs boson is the signature particle of a theory published by six physicists within a few months of each other in 1964. Peter Higgs at Edinburgh University was the first to point out that the theory called for the existence of the missing particle.

According to the theory, an invisible energy field fills the vacuum of space throughout the universe. When some particles move through the field they feel drag and gain weight as a result. Others, such as particles of light, or photons, feel no drag at all and remain mass-less.

Without the field -- or something to do its job -- all fundamental particles would weigh nothing and hurtle around at the speed of light. That would spell disaster for the formation of familiar atoms in the early universe and rule out life as we know it.

While the field is thought to give mass to fundamental particles, including quarks and electrons (the two kinds of particles that make up atoms), it accounts for only one or two percent of the weight of an atom itself, or any everyday object. That is because most mass comes from the energy that glues quarks together inside atoms.

To hunt for the Higgs boson, physicists at the LHC sift through showers of subatomic debris that spew out when protons collide in the machine at close to the speed of light. Most of the energy released in these microscopic fireballs is converted into well known particles that are identified by the collider’s giant detectors.

Occasionally, the collisions might create a Higgs boson, but it is expected disintegrate immediately into more familiar particles. To find it, scientists must look for telltale “excesses” of particles that signify Higgs boson decays. They appear as bumps, or peaks, in the data.

Speaking at the seminar, the scientists said they had narrowed down the range of masses the Higgs boson could have -- particle masses are measured in gigaelectronvolts (GeV), where one GeV is roughly equivalent to the mass of a proton, a subatomic particle found in atomic nuclei.

The CMS has excluded all Higgs masses except 115-128Gev, so between them the two experiments leave only 115-127GeV as the most probable Higgs mass, with both teams seeing signals between 124 and 126GeV.

Particle physicists use a “sigma” scale to grade the significance of results, from one to five. One and two sigma results are unreliable because they come and go with statistical fluctuations in the data. A three sigma result counts as an “observation”, while a five sigma result is enough to claim an official discovery. There is less than a one in a million chance of a five sigma result being a statistical fluke.

At Tuesday’s seminar, the Atlas team reported a 2.3 sigma bump in their data that could be a Higgs boson weighing 126GeV, while the CMS team reported a 1.9 sigma Higgs signal at a mass of around 124GeV. There is a 1% chance that the Atlas result could be due to a random fluctuation in the data.

Oliver Buchmueller, a physicist on the CMS experiment, said: “We see a small bump around the same mass as the Atlas team and that is intriguing. It means we have two experiments seeing the same thing and that is exactly how we would expect a Higgs signal to build up.” Early next year, the Atlas and CMS teams will pool their results, a move that should see the signals strengthen. Both teams are expected to need around four times as much data before they can finally confirm whether or not the Higgs boson exists. That might be difficult to collect before the end of next year, when the machine is due to close for at least a year for an upgrade before it can run at its full design power.

“There is definitely a hint of something around 125GeV but it’s not a discovery yet. We need more data! I’m keeping my champagne on ice,” said Jeff Forshaw, a physicist at Manchester University, England. “It should be said this is a fantastic achievement by all concerned. The machine has been working wonderfully and it is great to be closing in on the Higgs so soon.” The director general of CERN, Rolf-Dieter Heuer, said: “I find it fantastic that we have the first results in the search for the Higgs, but keep in mind these are preliminary results. The window for the Higgs mass gets smaller and smaller, however it is still alive. It’s intriguing hints in several channels, in two experiments, but we have not found it yet, we have not excluded it yet.” If the glimpse of the Higgs boson turns into a formal sighting next year, it may be one of several Higgs particles outlined in a radical theory of nature called super symmetry. The theory, which says that every known type of particle has an undiscovered twin, is popular among many physicists because it explains how some of the forces of nature might have behaved as one in the early universe. Unifying these fundamental forces was a feat that eluded Einstein to the grave.

Dick Hagen, a physicist at Rochester University who helped to develop the Higgs theory in 1964, said: “Einstein once said that God may be subtle but he is not perverse. Today’s results seem to favour the simplest manifestation of [the Higgs mechanism], and that is very gratifying as it coincides with the choice we made in 1964 -- not to mention the more personal issue that more complicated versions could easily fail to appear in the lifetimes of its principal authors.” © Guardian News & Media 2011

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"At the dawn of science, atoms were considered to be indestructible, then came the electrons, protons......etc. The quest to find answers to everything has lead scientists to Higgs particle today, who knows, the coming generations might be looking for sub sub Higg particle and this might never end and just give more questions rather than answers or after a century you might be surprised to find that, what ever has been assumed, thought was right, might be wrong!! But every discovery that was made has definitely increased the appreciation for the grandeur and how amazingly complex the nature of universe is. "

from:  Kalyan sreeram
Posted on: Dec 15, 2011 at 00:18 IST

#Raman: I certainly disagree with your comments on this topic. You are talking about using this money to feed poor's without thinking that for this purpose we need infrastructure, new advanced technology, modern factories and more than all of these, we need participation from people. Without these researches we are not going to increase productivity via modern technology.if you say that instead of bunking class newton and sitting under a tree he should have attended the class and learned what's so ever tought in class,then well my friend you live in largest democracy of world.In my views we have to develope new technology to pace up with the rate our population is growing,nothing in this world JUST happens,you have to make plans for future,you have to invest in present to secure the future.

from:  Anshuman raj
Posted on: Dec 14, 2011 at 19:41 IST

Too bad.. If it actually appeared for a Billionth of a second, the possibility of it starting the next "Big Bang", without any control measures in place, are a distinctive possibility.. Don't pay your Insurance Premiums... just yet..

from:  William Stewart
Posted on: Dec 14, 2011 at 19:21 IST

@Raman-Science is just not about Nobel prize and laboratories.This experiment may seem to you as extravagant and futile,but its implications and consequences are far reaching as well as highly rewarding.One more thing,the frugality you are talking about should be fostered in our lifestyle and the way we look at life.These bad times we find ourselves in is precisely because of greed and our intemperate outlook...Science and the quest for knowledge should not be the scapegoat for others' follies.I am suprised to see your parochial outlook.

from:  Aks Gupta
Posted on: Dec 14, 2011 at 19:12 IST

What a colossal waste of money that could have been well spent in other areas. These are frugal times and it demands a very frugal policy. Now, I am not against science, but questioning the wisdom and timing of it. Given all the financial difficulty that Globe at large is facing this was one extravagance we could have done with out. It is like having a feast watched by hungry! All to look for an elusive (an oxymoron) particle! So what are we going to do about it, now that we have some glimpse of it. Life for many will go on, but for the people in that lab fantasizing a Nobel prize.

from:  Raman
Posted on: Dec 14, 2011 at 17:13 IST
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