My Outlook India article on the LHC

My article on the LHC has just appeared in Outlook India, on page 123 of the print edition of the B-school special, dated September 29, 2009 2008. There was no space for acknowledgements, but this would not have happened but for Diptiman Sen, Sudhir Kumar Vempati and S. Uma Sankar, and also Debasish Ghosh of Aerospace who I have never met. So this may be considered the acknowledgement.


Update: Thanks to Abbas Ali for pointing out the error in the date!


Here is the link.

It is reproduced below for fear of link rot (I have checked with the South India Associate Editor that it is ok to do this.)


Subatomic Slugfest

The CERN experiment is the Apollo moon mission of particle physics


B. Ananthanarayan




On September 10, when the first proton beam was injected into the 'Large Hadron Collider' (LHC) at CERN, in Geneva, science began an exciting new voyage of discovery. The LHC is an awesome machine that will collide intense beams of protons, which will be accelerated in two rings of 27 km circumference. The energy would be seven times larger than the highest ever achieved by accelerators. Four immense detectors will surround the four interaction points of the collisions, and detect the particles produced in the fireball of the impact. At a later stage, the protons will be replaced by nuclei of lead atoms to replicate conditions similar to those that existed at the time of the Big Bang.

Likened to the Apollo moon mission in grandeur, the LHC—an engineering marvel—is the result of the effort of thousands of scientists and engineers, whose purpose is to advance their understanding of nature at its most minuscule scale, which can be probed only with the highest energies. And past great discoveries have come with higher and higher energies. These discoveries have had massive spinoffs in technology: indeed, CERN is the mother of the worldwide web, just as the space programme led to the revolution in materials, and nuclear physics is at the heart of the modern cancer therapy.

The LHC was built at a cost of billions of Swiss Francs by CERN member-states, along with the participation of countries like India, which enjoys 'observer' status. It is a proud moment for many players from India—among these, the DAE Raja Ramanna Centre for Advanced Technology, barc, tifr and others have played notable parts, and teams from universities and research institutes have been involved at many stages of the project. ECIL, BHEL, Kirloskar Electric Co. Ltd, Crompton-Greaves Ltd are among companies that have participated in r&d and fabrication of components. The LHC project has demonstrated the coming of age of Indian science, technology, engineering and manufacturing in the 21st century.

The LHC will carry out its explorations in the deep sub-nuclear domain. Whereas people are familiar with chemistry as the science of atoms and molecules, we now know that atoms are made of nuclei and electrons, and nuclei of protons and neutrons, and protons and neutrons of quarks (and gluons). We have a picture of the elementary particles in nature, and how they participate in the electromagnetic interaction, weak and strong. The first arises from electrically charged particles interacting via the exchange of force carriers, namely mass-less photons, not unlike two children (electrons) who throw a tennis-ball (photon) back and forth in a game. The weak interactions lead to the decay of some radioactive isotopes, and also of free neutrons. Thus they are significant only at the sub-nuclear scale, and one may surmise that the corresponding force carriers are extremely massive. The strong interactions are those that trap quarks and gluons inside hadrons. There are also heavier quarks than those in protons and neutrons, all of which would have been abounding around us, but for the weak interactions, which lead to their spontaneous decay. Electrons too have heavier unstable cousins, and each of these have electrically neutral counterparts are known as neutrinos.

If indeed the electromagnetic and weak forces have a common origin as we now believe, how is it that the photon remained mass-less while the force carrier of the weak forces became massive? The question was answered by Peter Higgs in the 1960s, but at a price—a thus far undetected particle, the Higgs boson. With the gigantic energy in the collisions at LHC and the rates of collisions available here, we may at long last discover this particle. There has been gathering evidence for decades, and more recently of direct imprints, of so-called 'dark matter' in galaxies.Such particles will be produced in the fireballs of the LHC collisions and would leave distinct signatures in the detectors.

There have been many questions in the public mind about the project's safety. In popular theoretical scenarios, microscopic black holes are predicted to exist. If produced, they present no danger, as they bear no relation to the super-massive black sholes present in the centres of galaxies, and consequently we need have no fear of these! Furthermore, they would decay into conventional particles as a consequence of the results established by Steven Hawking.

It may yet be that the LHC will reveal wonders that no one has dreamt of. The voyage has just begun.



(The author is associate professor at the Centre for High Energy Physics, Indian Institute of Science, Bangalore, and serves on the Board of Editors of the European Physical Journal)