Showing posts with label Particle Physics. Show all posts
Showing posts with label Particle Physics. Show all posts

Thursday, July 5, 2012

Discovery of 'God particle'

Israelis rejoice over discovery of 'God particle'
07/04/2012

Scientists revel with colleagues around world over discovery in Geneva of new sub-atomic particle.

Scientists explain search for Higgs boson particle
Photo: REUTERS

Theoretical and experimental physicists see the groundbreaking discovery of a new subatomic particle – announced Wednesday in Geneva – as even more of a technological and scientific achievement than America’s first landing on the moon. But unlike the astronauts’ romp over the dusty lunar rocks in 1969, the new breakthrough is so intangible that it leaves the general public clueless.

Scientists at Geneva’s European Laboratory for Particle Physics (CERN) – where scores of Israelis have worked for decades to bring the discovery nearer – confirmed that they had discovered a particle fitting the description of the Higgs boson, the so-called “God particle” seen as key to understanding how the universe is built. It was suggested in 1964 by six physicists – including University of Edinburgh physicist Peter Higgs, the particle’s namesake – as a way to explain mass.

At a morning press conference in Geneva, CERN Director-General Rolf-Dieter Heuer said, to the cheers of scientists and reporters, “We have a discovery. We should state it. We have a discovery! We have observed a new particle consistent with a Higgs boson.”

The Higgs particle, although crucial for understanding how the universe was formed, remains theoretical.

It explains how particles clumped together to form stars, planets and even life. According to the theory, without the Higgs particle, the particles that make up the universe would have remained a primordial soup.

In particle physics, bosons are one of the two fundamental classes of subatomic particles, the other being fermions. The Higgs boson is the final building block that has been missing from the “Standard Model,” which describes the structure of matter in the universe. The model is for physicists what the theory of evolution is for biologists.What scientists don’t yet know from the latest findings is whether the particle they have discovered is the Higgs boson as described by the Standard Model, a variant of the Higgs or an entirely new subatomic particle that could force a rethink on the fundamental structure of matter.

Knesset Science and Technology Committee chairman Ronit Tirosh said Wednesday that she was “very proud of the contribution of Israeli scientists [to] the discovery.”

Astrophysicists from the Weizmann Institute of Science in Rehovot, Tel Aviv University, the Technion-Institute of Technology in Haifa and the Hebrew University of Jerusalem have been active in the massive effort, which involved CERN’s particle accelerator – the largest machine in the world, costing over $10 billion.

Prof. Yaron Oz, dean of TAU’s faculty for exact sciences, who worked on CERN’s multinational team at Geneva for four years and has made numerous visits since, told The Jerusalem Post in an interview that the huge facility “is like the UN should be. Everybody is devoted to making the discovery as a team, without any politics or vested interests. I worked even with Iranians there, and there was never a harsh word between us. We all just wanted to understand. It has already proven that the nations of the world can function harmoniously for joint targets.”

The Large Hadron Collider (LHC) particle accelerator is based on superconducting electromagnets working at very low temperatures: less than two degrees above absolute zero (-271° Celsius). This experimental system includes the world’s largest superconducting electromagnets, built in conjunction with Israeli companies. The entire structure includes 10,000 radiation detectors spaced just one millimeter apart, has a volume of 25,000 cubic meters and features half a million electronic channels. Most of the muon radiation detectors were built from components produced in Israel.

While the foremost concern is a better understanding of the origins and development of the universe, Oz had no doubt that in the future, various new technologies would result that would benefit mankind.

In the first stage after the announcement, “people won’t feel a change unless they are interested in the universe. Later, the public will feel an improvement in computerization and other technology. Even health benefits could result. The aim was not to create a product. No layman knew what quantum mechanics and lasers were, but today, these are in all electronic household appliances.

Nuclear physics is used on a daily basis to treat cancer patients.”

Oz said he thought Albert Einstein “would have been very happy today. He had even larger targets – the United Field Theory. We are not there yet, but we hope the Large Hadron Collider will lead to this.”

Asked about the term “God particle,” Oz said that “one has to separate science from religion. This phrase does not refer to divinity.”

His TAU colleague Prof. Aharon Levy, who is modern Orthodox and has headed a research group in Hamburg, agreed. “The term originates with Max Lederman, an American experimental physicist who won the Nobel Prize in physics for his work with neutrinos. He wrote a book using this term, by which he meant the mysterious particle being part of everything. First, everything was created without mass. Particle physics aims at understanding what conditions created the Big Bang that created the Universe, to look backwards as much as possible to that event.”

As a religious person, Levy said the discovery “does help us understand how much we don’t understand about the universe. A religious Jew might say the discovery shows the orderliness of nature that is evidence that the universe was created by a Divine power, but we don’t get involved in this.”

There was much excitement at the Weizmann Institute as well. Prof.

Giora Mikenberg was the ATLAS Muon Project leader for many years and now heads the Israeli LHC team. He, Prof. Ehud Duchovni and Prof. Eilam Gross of the Rehovot institute’s particle physics and astrophysics department, have been part of the effort to find the Higgs boson since 1987.

“I have been searching for the Higgs since I was a student in the 1980s,” Gross enthused. “Even after 25 years, it still came as a surprise.

No matter what you call it – we are no longer searching for the Higgs but measuring its properties.

Though I believed it would be found, I never dreamed it would happen while I was holding a senior position in the global research team.”

The LHC particle accelerator enables collisions of particle beams that create conditions similar to those that existed in the first fraction of a second after the Big Bang. The likelihood of creating the Higgs boson in a single collision is similar to that of randomly extracting a specific living cell from the leaf of a plant, out of all the plants growing on Earth. To cope with this task, Mikenberg developed specific particle detectors manufactured at Weizmann, and in Japan and China.

The calculations that scientists, including Gross, carried out in recent months played a central role in finding the particle, as they revealed, with a high degree of statistical significance, a new particle with a mass similar to the expected mass of the Higgs. The wording is purposely cautious, leaving room for the possibility that a new particle other than the Higgs could be found within this mass range. The probability that this is, indeed, a new particle is quite low, the Weizmann scientists concluded.