Search for the God Particle

The (Higgs’) boson is so central to the state of physics today, so crucial to our final understanding of the structure of matter, yet so elusive, that I have given it a nickname: the God Particle. Why God Particle? Two reasons. One, the publisher wouldn’t let us call it the Goddamn Particle,

though that might be a more appropriate title, given its villainous nature and the expense it is causing. And two, there is a connection, of sorts, to another book, a much older one…. (Leon Lederman with Dick Teresi, The God Particle, pp. 22-23)


The other, much older, book that Lederman has alluded to in the frontispiece is of course the Bible (Genesis 11: 1-9). He has described these verses under a cynical title of “The Tower and the Accelerator.” The tower is the Babel Tower. And then he has parodied these verses under “The Very New Testament, 11: 1,” in which he has written:

“And the Lord came down to see the accelerator, which the children of men builded. And the Lord said, Behold the people are unconfounding my confounding. And the Lord sighed and said, Go to, let us go down, and there give them the God Particle so that they may see how beautiful is the universe I have made.”

And the metaphorical name stuck fast like the super-glue. Some scientists including Peter Higgs don’t like this name. According to Ian Sample (The god of small things, Guardian, November 17, 2007), “The name has stuck but makes Higgs wince and raises the hackles of other theorists. ‘I wish he (Lederman) hadn’t done it,’ he says. ‘I have to explain to people it was a joke. I’m an atheist, but I have an uneasy feeling that playing around with names like that could be unnecessarily offensive to people who are religious.’”

What is the God Particle?

According to Peter Rogers, Editor of Physics World, “In 1993 the UK’s science minister at the time, William Waldegrave, asked physicists to explain in simple terms – and on one side of A4 – what the Higgs boson is, and why they wanted to find it. With a bottle of vintage Champagne on offer for the best explanation, physicists rose to the challenge with analogies that ranged from cocktail parties to space having a ‘grain’ like a piece of wood, albeit in an abstract space rather than real space. In the latter example, particles that travel with the grain have no mass, like the photon, while those that travel against the grain have large masses, like the W and Z bosons.”

A similar story of selling the Superconducting Super Collider (SSC) to President Reagan is described by Ian Sample and a different version is described by Lederman in The God Particle. According to Sample, “The man charged with selling the SSC to Reagan was Alvin Trivelpiece, then director of the office of energy research. Tivelpiece, an exceptionally astute physicist, had heard the president’s sight was failing, and prepared his presentation on two large easels, which he dragged into the Oval Office. There, he likened the SSC’s task to using the bullets to find billiard balls hidden in bales of hay. ‘I knew the one thing they would understand was guns,’ Trivelpiece told me.”

The project was however cancelled by the Congress in 1993 because it was very expensive to build. Its estimated cost was more than 12 billion dollars.

These brilliant analogies aside, let me explain as follows. In 1964, Peter Higgs formulated a field theory, which now is called Higgs theory, and showed how the particles acquire their mass. Ever since Newton had introduced mass in his work, majority of the scientists took mass as granted – it simply existed and was there. Many others were however puzzled. Higgs theory explained how the elementary particles acquire mass. According to Higgs theory, mass is “produced by a new type of field that clings to particles wherever they are, dragging on them and making them heavy. Some particles find the field more sticky than others. Particles of light (massless photons) are oblivious to it. Others have to wade through it like an elephant in tar. So, in theory, particles can weigh nothing, but as soon as they are in the field, they get heavy,” (Ian Sample). This explanation is so fundamental that the physicists believe Higgs theory is basically correct and the evidence for its correctness should exist. Hence the rationale for finding the Higgs boson.

The messenger particle of this field is called Higgs boson, the god particle. If this particle is found Higgs theory will be vindicated. Ever since this theory was propounded and its initial success demonstrated by Weinberg and Salam who unified the electromagnetic and weak forces using the mechanism Higgs had suggested, the search is on for the god particle. Pursuit of no other scientific theory has been neither so intensely single-minded nor so expensive, even the search for cure for cancer, as the search for Higgs boson. It is so because very much depends on it. The theory provides explanation to dark matter, dark energy and host of other important missing pieces in physics and might further help to unify the fundamental forces of nature which the string theorists and other physicists are trying so very hard to achieve.

Although the god particle is technically called Higgs boson after Peter Higgs, Higgs work was preceded by the work of two others. They are Robert Brout and Francois Englert. They published their independent work a few weeks earlier than Higgs. Somehow Higgs name got stuck as the name of the particle. One of Higgs’ colleagues presented a seminar in Germany and described the particle as Higgs particle. Robert Brout was sitting there in the front row and when the lecturer saw him and realized his mistake, he tried to amend it by saying, “Of course I know this was also discovered by others but I refer to it with the shortest name. ‘My name has five letters too,’ piped Brout,” (Ian Sample).

Accelerators and the Colliders

One can not understand the physics of the past several decades without understanding the nature of the accelerator and its accompanying array of particle detectors, the dominant tools in the field for the past forty years. (Leon Lederman)

Soon after 1909-11 when Ernst Rutherford and his students collaborated to conduct the scattering experiment by bombarding a gold leaf with the alpha particles, a new experimental physics, high energy physics, was born ushering the era of the accelerators and colliders. The underlying idea was quite simple (in the hindsight). We can study the intricacies of the structure of an atom if its nucleus is smashed to yield its constituent subatomic particles. In order to do so, we need very high energies to smash the nucleus or other subatomic particles. Effectively, by doing so we are trying to simulate the physical condition that prevailed in the universe instantaneously after the big bang and before the cooling began after sudden inflation. At that time, matter was in the form of atoms and subatomic particles. After the inflation, the universe cooled and the particles coalesced to form huge lumps of mass in the form of the stars and galaxies.

Higgs boson is very unstable and is prone to decay instantaneously. If we want to detect the existence of a Higgs boson, we need first to create it by smashing subatomic particles using the required amount of energy and then detect it instantaneously. Hence the need for the super-energetic colliders and highly sensitive detectors.

Many universities and research centers have accelerators of various kinds and various sizes which are appropriate to their educational and research needs and more importantly which they can afford. It is not intended herein to describe all these various accelerators or even enumerate them; only those which are relevant for detecting the Higgs boson will be briefly mentioned.

According to Lederman, “..the Higgs particle with the lowest mass (there may be many) must ‘weigh’ less than 1 TeV, “(The God Particle, p.376). And he also wrote, “There is no accelerator on earth (as of 1993, the date of publication of his book) that has the energy to create a Higgs particle as heavy as 1 TeV. You could however build one,” (p. 376).

The situation has changed since then. By the way, 1 TeV is equal to 10^12 (1 trillion) eV. One eV is the kinetic energy gained by an electron passing through a potential difference of 1 volt.

Great hopes of finding Higgs boson are pinned on the Large Hadron Collider (LHC) located at CERN (European Council for Nuclear Research) near Geneva, Switzerland. It is due to be operational by May 2008. “The collider is contained in a tunnel with a circumference of 26.659 kilometer, at a depth ranging from 50 to 175 meters underground,” (Large Hadron Collider, Wikipedia). The tunnel was formerly used to house the LEP (Large Electron Positron) collider. The LEP was one of the largest accelerators ever made which could accelerate the electrons and positrons to a total energy of 45 GeV (billion eV). It was designed to capture the Z boson which has a mass of 91 GeV. The LEP was shut down near the end of 2000 to make room for the LHC. It operated from 1989 to 2000.

While it is almost certain that the LHC will create Higgs boson, if such a particle ever existed, encouraging data is coming out of the Fermilab near Chicago (Batavia). The Tevatron which is located in a 4 mile long circular tunnel is presently the most powerful accelerator in the world with an energy of 2 TeV (LHC will surpass it when it becomes operational next year). It thus is suitable to detect Higgs boson.

The SSC was intended to enhance the capability of the Tevatron but was cancelled by the Congress in 1993 as already mentioned above. One of the other reasons (apart from the cost) for its cancellation was speculated to be the end of the cold war and competition with the USSR. The LHC will essentially serve the purpose which was intended of the SSC.

Are We There Yet?

A rumor flying around physics departments these last few weeks claims that physicists working at the Tevatron, an accelerator located outside of Chicago, have found something new. Originally passed by word of mouth and private e-mail, the rumor made it into the blogosphere May 28 (2007), with an anonymous comment on the blog of a particle physicist living in Venice, Italy. Since then, the rumor has spread, (Owen Weatherall, Quantum Scoop, June 4, 2007).

The rumor is just a rumor without any reliable confirmation from any trustworthy source. However, it did spread far and wide and generated a lot of excitement among the bloggers. Dennis Overbye, a science reporter for The New York Times, discussed it at length in his article (At Fermilab, the Race is on for the God Particle, July 24, 2007).

There had been rumors in the past also. Previously, a rumor spread that Higgs boson was detected from “a signal obtained at the large electron-positron collider (LEP) in Geneva, Switzerland, which has now been dismantled to make way for the large hadron collider,” (God particle may have been seen, BBC News Online science staff). Nothing came of it.

Earlier this year, a rumor was attributed to John Conway, a physicist belonging to the Collider Detector at Fermilab (CDF), that his “team had found a signal which, in particle physics had a 2-sigma (standard deviation) significance – a 1 in 50 chance of being a random fluctuation. Normally, to merit new particle status a signal must be significant to 5-sigma – where there’s only a 1 in 10 million chance of it being a fluctuation.” So why all this excitement? It was believed that this particle may be one of the five Higgs particles predicted by the super-symmetry theory. But it all fizzled out later.

In December 2006, a claim was made based on the information coming out from the University of Buffalo (UB) that a “cousin of Higgs boson was detected.” It was attributed to Dr. Piyare Jain, UB professor emeritus in the Department of Physics, who claimed that “a particle with no charge, a very low mass and a lifetime much shorter than a nanosecond, known as the axion, has been detected,” (http://www.scienceagogo.com/news/20061106200405data_trunc_sys...). “This particle was in my original paper in 1974,” Jain said.

In spite of all this hype, Higgs boson remains elusive as ever. The hype has heightened also in anticipation of the LHC coming on line next year when it’s almost certain that Higgs boson will be discovered, if it is real. Also, a sense of competition makes it more exciting. According to Dennis Overbye, “Robin Erbacher of the University of California, Davis, said, ‘We’re absolutely in the game.’ It would be a shame, she said, if a Higgs signal overlooked at Fermilab is discovered and trumpeted at the CERN collider.”

In conclusion, we are not quite there yet although we’ll be there next year or soon after.