The discovery of a new particle at the Large Hadron Collider (LHC), which in all likelihood is the Higgs boson — the particle desperately sought after by physicists for decades — may not change our lives but it is important for our understanding of the sub-atomic world that determines the universe at large. The Higgs is the crucial missing link in a theory of the known fundamental particles and forces of nature (save gravity) called the Standard Model. While the theory gives a unified description of the disparate forces of nature, the underlying mathematics requires all particles to be massless, which is certainly not the universe we live in. In the early 1960s, Peter Higgs, among others, hypothesised the existence of an energy-field and an associated particle — the Higgs field and the Higgs boson respectively — which enabled the particles to acquire mass without destroying the unification of forces in a single mathematical framework. The theory has withstood all high precision tests that have been done to verify its correctness but the Higgs particle itself has eluded detection since the 1990s when high-energy accelerators began their focused search for it. The Large Electron-Positron collider at CERN had ruled out the existence of Higgs below a mass of 115 GeV before it shut down in 2000 to make way for the higher energy LHC. The search was picked up by the Tevatron at Fermilab in the U.S. Just two days before CERN’s landmark announcement, Fermilab scientists announced that if the Higgs particle exists, it has a mass between 115 and 135 GeV, a result that provides an independent validation of LHC’s results.
The LHC began its operations in March 2010 and by December 2011, there were already hints of a Higgs-like signal in the data but its statistical significance was low, with a 1-in-750 chance of getting it wrong. The latest data revealing the existence of a 125 GeV mass particle — with just a 3-in-10 million chance of being wrong — marks a high-point in precision experimental high-energy physics. The quality of data that it has produced in such a short period is certainly unprecedented. The extraordinary performance of the accelerator and the detectors, and the high quality data extracted through improved analytical techniques, is due entirely to the pooled-in skill and brains of thousands of scientists from all over the world, including India. True, this is just the beginning of a long journey when other properties of this new particle will be scrutinised to see if it indeed is the Higgs boson that scientists were looking for, or some other beast altogether. If it is the latter, it would raise many more questions and open new avenues for other ideas in our attempt at understanding the universe.