My take on unravelling the Higgs Boson...

It was grand day at CERN in Geneva when the physicists announced the discovery of the by now famous particle known as the Higgs Boson. Over time this has been come to be known as the God Particle. Like a search for God, this particle has been a very elusive customer – is that why perhaps it has been so called? In any case, this is a very important discovery for the Standard Model of Physics which is a model of how all interactions take place in nature. All the particles predicted by the Standard Model have been seen in experiments except this one, that is why it becomes such an important discovery. 

What is the Standard Model? To understand that, we have to know that physics is based on the concept that there are fundamentally only four forces in nature – Electromagnetic, Strong, Weak and Gravitational. The aim of physics is to construct a theory that will explain all of these forces completely. The theory that describes three of these interactions is known as the Standard Model. It describes Strong, Weak and Electromagnetic interactions and attempts are on to unify this with a theory of gravity.

In the 1960s, during the unification of the weak and electromagnetic interactions,the theory demanded that there should be a heavy particle which decays to give the other particles their mass. This was the theory of the Higgs. The theory predicted the mass of the Higgs particle. This particle would differentiate between the photon, which is massless and the field particle of the electromagnetic field, and the W and Z bosons, which are heavier and correspond to the weak field. In the standard model, the strong interactions are also unified and the quarks and gluons, which are the fundamental particles involved in strong interactions come into the picture. So it came about that the Higgs particle when it interacts with other particles, gives them a mass in proportion to the strength of its interaction.

Now all was right with the theory. However the practice proved to be really difficult. Particle physicists had their time cut out trying to find this particle. They devised several high-energy proton collision experiments in which they expected to see this particle but it kept eluding them. Finally after about fifty years of search and research, at CERN in Geneva, in two separate experiments, physicists sighted a bump in the spectrum which corresponds to a particle with a mass 125 gigaelectronvolts. The mass is close to that predicted by the theory. From the frequency of occurrence of this bump in collision experiments, they have concluded it is not just a resonance, or a short lived quantum state, but a real proper particle, and that too, the elusive Higgs itself! They need to go through a few more experiments to confirm this absolutely. But to all intents and purposes, as Rolf Heuer, Director of the European Centre for Nuclear Research (CERN) put it, ‘As a layman, I think we did it. We’ve a discovery. We’ve observed a new particle that is consistent with the Higgs Boson.’