Thursday, July 5, 2012

Quantum Leap in Physics: Scientists Spot Subatomic Particle

Scientists at Switzerland's European Organization for Nuclear Research, famously known as CERN research center in Geneva have made the historic announcement, in a major milestone in the 50-year search for the elusive Higgs, that is believed to have been responsible for lending mass to the particles that eventually formed the stars and the planets after the Big Bang 13.7 billion years ago. They claimed to have spotted a subatomic particle “consistent” with the Higgs boson or “god particle,” believed to be a crucial building block that led to the formation of the universe. These results mark a significant breakthrough in the understanding of the fundamental laws that govern the universe.

The phrase “god particle” was coined by Nobel Prize-winning physicist Leon Lederman but is used by laymen, not physicists, as an easier way to explain how the subatomic universe works and got started.

Discovery and Its Significance
The particle was proposed in 1964 by three groups of physicists, including Britain’s Peter Higgs, after whom it was named. The announcement was linked to a seminar at CERN, where the latest results from the ATLAS and CMS experiments were revealed. It came after a video leak hinted the new particle might have been found.

The results were labeled as preliminary, based on data collected in 2011 and 2012, with the 2012 data still under analysis. But scientists are 99.99 per cent sure the new particle is Higgs Boson, or the “God particle,” as it is better known.

Prof. John Womersley, chief executive of the Science and Technology Facilities Council (STFC) said: “Obviously there is still much, much more to do at Large Hadron Collider (LHC), the world's biggest and most powerful particle accelerator. — we need to confirm this new particle is (why) some particles have tangible mass while others are insubstantial... Peter Higgs and other scientists predicted a particle like this one must exist for our current understanding of the universe to work.”

With all necessary caution, it looks to me that we are at a branching point: the observation of this new particle indicates the path for the future towards a more detailed understanding of what we’re seeing in the data.

The Higgs discovery can be described “as significant to physics as the discovery of DNA was to biology. This is the physics version of the discovery of DNA. It sets the course for a brand new adventure in our efforts to understand the fabric of our universe.

The Higgs boson, which until now was a theoretical particle, is seen as the key to understanding why matter has mass. It is mass that combines with gravity to give an object weight. The idea is much like gravity and Isaac Newton’s discovery of it. Gravity existed even before Newton explained it. But now scientists see something much like the Higgs boson and can put that knowledge to further use.

A five sigma, that translates into over 99 per cent certainty of discovery, is required before a particle is declared as being discovered. Plus, the Higgs is believed to lurk at the lower ends of the energy spectrum – between 120 and 140 GeV.

India’s Footprints
As all eyes are on the CERN, Indian scientific and technological contributions are among the many that keep the world’s biggest particle physics laboratory buzzing. There is an intrinsic Indian connection to what is happening at CERN — Satyendra Nath Bose, a contemporary of Albert Einstein. It is Bose after whom the subatomic particle boson is named.

His study changed the way particle physics has been studied ever since. The Higgs Boson is a particle that is theoretically the reason why all matter in the universe has mass.
Bose's work on Quantum Mechanics was adopted by Einstein, who extended it to the concept of the Bose-Einstein condensate – a dense collection of bosons, subatomic particles with integer spin. For the past 50 years, finding the missing Higgs was one of the most puzzling riddles of Quantum Physics, and led scientists to set up the 3 billion euros LHC.

The 27-km looped pipe set up in a tunnel 100 meters underground on the Switzerland-France border created artificially simulated conditions similar to the Big Bang, triggering collisions between accelerated particles.

In the LHC experiment, two beams of protons are fired in opposite directions to smash millions of particles into each other every second, a set up that recreates conditions that existed a fraction of a second after the Big Bang. This is the time when the Higgs field is believed to have come into play. The Higgs particles are believed to have transferred mass to the millions of other particles in the process of creation of the universe.

The scientists then look into conditions that might point to the existence of the mysterious particle. As the Higgs cannot be seen, its existence is only to be inferred from circumstances.
Moreover, the Saha Institute of Nuclear Physics (SINP) said in Kolkata that its scientists had made significant contributions to the development of the CMS experiments at CERN. This led to the observation of the new particle at 125.3 GeV, consistent with a Higgs Boson as predicted by the Standard Model of Particle Physics. It will require more data and intense scrutiny to establish these findings beyond any doubt.

The core CMS team of the SINP had five faculty members — group leader Prof. Sunanda Banerjee, Prof. Satyaki Bhattacharya, Prof. Suchandra Datta, Prof. Subir Sarkar and Prof. Manoj Saran.

Most of the team members had worked for more than a decade with the CMS experiment with notable contributions in the development of the experiment right from the early stage and were actively participating in the analysis of the incoming data.

Standard Model
The Standard Model -- a hypothesis devised in the 1970s to explain the events after the Big Bang – identifies the building blocks for matter.

Finding the Higgs particle would validate the Standard Model that is a hugely successful theory but has several gaps, the biggest of which is why some particles have mass but others do not. Without the Higgs boson, the universe could not exist, as everything would behave as light does, floating freely and not combining with anything else, the scientists believe.

CERN's data was kept closely guarded but just before the official announcement a video from the CERN center that mistakenly found its way on the web, appeared to have given away the secret.
Moreover, it is believed that the LHC will continue to run its experiments so that results revealed can be revalidated before it shuts down at the end of the year for maintenance. Even so, by 2013, scientists, such as Dr. Rahul Sinha, a participant of the Belle Collaboration in Japan, are confident that a conclusive result will be out.

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