Higgs boson may be the new Big Bang of particle physics



“Elementary, my dear Watson” is a turn of phrase often ascribed to Sherlock Holmes, the fictional master detective who cracked one seemingly unsolvable mystery after another in Arthur Conan Doyle’s thrillers.

In real life, however, physicists laboured for over four decades before they could chance upon the first piece of evidence that proves the existence of one elementary, sub-atomic particle – the Higgs boson. To the list of elementary particles like electrons, protons, neutrons, quarks, leptons et al could well be added the Higgs boson, named after the Scottish physicist Peter Higgs and India’s own Satyendranath Bose.

The `big bang’ discovery about the elusive Higgs boson particle could well mark the beginning of new discoveries in physics, says Prof Sridhara Rao Dasu of the University of Wisconsin, one of the leaders of a sizeable team pursuing the `historic’ hunt launched for detecting the particle. The search party used the Large Hadron Collider (LHC), the biggest `atom smasher’, at the Centre for Nuclear Research (CERN), Geneva.

ATLAS and CMS, the two groups each with around 3000 members, of whom about 2000 each are scientists and Ph.D students, announced on Wednesday that they found evidence for the new particle that is consistent with the famous Higgs boson.

Dr Sridhara told Business Line in an interaction from the US that over a hundred of these scientists on CMS are of Indian origin, mostly participating through collaborating institutes in India: TIFR, BARC, SINP, Universities of Delhi and Punjab. “In addition there are several Indian expatriates, who are members of teams from foreign institutions, mostly in the US,” he stated.

The Indian contribution, starting ab-initio from Satyendra Nath Bose’s work lending the name to Higgs boson, has been quite significant. The Department of Atomic Energy has been a major provider of instrumentation for the LHC. Similarly, a team from the Saha Institute of Nuclear Physics (SINP), Kolkata, contributed to the software for the detectors used for experiments.

Dr Sridhara, a post-graduate from the University of Hyderabad and doctorate from the University of Rochester, has been associated with the Superconducting Super Collider project and the CERN programme for years. He heads a 25-member strong research group from the University of Wisconsin that played crucial roles in design and construction of the CMS experiment, its electronics and grid computing facilities, and continues to operate and improve their performance.

“My group plays a leadership role in the studies of tau-lepton and Z-boson pair decay modes of the Higgs. We have observed a small excess in the Z-boson pair at ~125 GeV compatible with the main result based on photon-pairs, boosting the overall significance to the five standard deviations level, that we use as a benchmark to announce the discovery. We have not yet observed the new particle in its decays to tau-leptons”.

These results will be presented at the International Conference on High Energy Physics at Melbourne this Saturday. Detailed studies such as these and others being done elsewhere will be important to determine whether this particle is the SM Higgs boson or not, he added.

There are many reasons to speculate that the Standard Model (which accurately describes the fundamental particles and forces of nature) in particle physics is not complete, most important of which is that the SM particle content cannot account for the dark matter in our universe. Theories beyond the SM can provide dark matter candidates, and many such theories predict additional Higgs boson-like particles. Many surprises could await us in this new field. The LHC is performing very well and it will enable us to present a more complete picture of our understanding of the universe at this fundamental level in the next few months, Prof. Sridhara said