Ashwini Kumar Rath
A huge excitement has gripped physicists with the recent set of data from the subterranean 27 kilometer-long (circumference) accelerator at CERN near Geneva. Even though the ‘Standard Model’ of physics will get another proof of its validity, it is also a testimony of performing technology marvel by humanity due to involvement of high-level of engineering efforts and large-scale computation. In this article, we would strive to understand this ‘God particle’ and the current excitement associated with it.
What Is This ‘God Particle’?
The ‘God particle’ is actually called ‘Higgs boson’, and is a subatomic particle. The existence of this elementary particle was predicted with the ‘Standard Model’ – the dominant theoretical model to explain physical phenomena in the subatomic world. This model integrates three of the four forces of Nature, electromagnetic, strong and weak forces, excluding just the only other force, the gravitational force. The built-up of this theory spanned over several decades in the later part of 20th century, and saw a few instances of coveted Nobel prize being awarded due to discoveries of different elementary particles as predicated by this model.
The ‘Standard Model’ demands the existence of quantum field, called Higgs field (named after the English theoretical physicist, Peter Higgs), around particles which will account for their mass. In fact, at the subatomic scale, the mass has been invariably associated with energy units through the equation
, giving approximately
for Higgs field potential energy. On the other hand, quantum theory in physics has made us belive in the wave-particle duality - a perspective where a wave can be treated as a particle and vice versa. (Well, this is prominent particularly in the subatomic world; so treat people around you in the same way at your own risk!) This argument points to the existence of 'Higgs field' particles around all particles which contribute to their 'mass'. Well, these are Higgs particles or Higgs bosons, their name being drawn from the quantum field. Media banked on the name 'God particle' while referring to this elementary elusive particle after the book, 'The God Particle: If the Universe Is the Answer, What Is the Question?' by Leon M. Lederman and Dick Teresi; thus overstated its importance. Even a renaming competition was conducted by the 'Guardian' newspaper where the new name 'champagne-bottle particle' was chosen due to resemblance of a champagne bottle to the potential (graph) used to describe the particle. Going further, media has also compared the 'Higgs mechanism' with the movement of celebrities within a party - a celebrity moves with the cluster of 'heavy' people, and if he/ she stops, remains stationery with the cluster - enough food for thought to come with another analogy!
Importance of Higgs Particle
Like any theoretical prediction, the evidence for further validity of the 'Standard Model' will be achieved if Higgs boson is found in reality. Moreover, the experimental conditions for visualizing the existence of this particle requires that similar to the early universe, when the universe was only a trillionth of a second old. This is immediately after the 'Big Bang' when these particles freely participated in mutual interactions to give rise to the universe as we see today. Discovery of this particle will help in integrating 'Gravitation theory' which has not been the part of the 'Standard Model' as well as explaining the origin of the universe. Of course, immediate importance of Higgs particle lies in its ability to explain the origin of 'mass'.
Search for Higgs Boson
The search for Higgs boson has challenged our engineering and computational capabilities. The experiments designed to recreate the early universe scenario and to study the behaviour of these particles to draw inferences have been quite expensive. Early efforts with 1 TeV Tevatron at Fermilab in Illinois, have enabled us to find several elementary particles as predicted by the 'Standard Model' like the six varieties of 'quark' (three of these elementary particles make a 'proton'). Later, the accelerator at CERN, Large Hadron Collidor (LHC), has been the center of focus for all when two beams of protons collide while speeding at near-light speed, thus recreating the early universe scenario perfect to find the particle in question. Two general-purpose experiments, Compact Muon Solenoid (CMS) and ATLAS are conducted at the LHC with which physicists hope to detect the Higgs boson.
The main conclusion from the recent experiments is that Higgs particle, if it exists, is most likely to have a mass within the range 116-130 GeV (ATLAS experiment), and 115-127 GeV (CMS experiment) complying with the theoretical model. Though these data are exciting with indication of possible existence of the 'God particle', findings are not strong enough to claim a discovery.
The usual estimate of a couple of decades of further effort required to unravel all the predictions of the 'Standard Model' can be discouraging, and would require persistent effort on the part of physicists, technologists and computational scientists apart from convincing the world leaders to invest in such human endeavour. Of course, there are 'Higgless theories' that do not require the existence of Higgs boson to explain subatomic physical phenomena; and people may shift their plank subsequently! However, the search for finding an universal model for all physical phenomena will continue, and thus the search for the 'God particle' will be a part of this larger effort.