The scientists working at the CERN Laboratory are expected to reveal the existence of an elusive piece of the particle physics, the Higgs boson. that they believe can help solve the puzzle of the origins of our universe. But how did they come to this stage?
A particle accelerator at the CERN laboratory. AP
In a detailed video, Meenakshi Narain, Professor of physics in Brown University, explains the working and structure of the various machines that the scientists at CERN in their attempt to prove the existence of the long elusive Higgs boson.
The Higgs is the last missing piece of the Standard Model, the theory that describes the basic building blocks of the universe. The other 11 particles predicted by the model have been found and finding the Higgs would validate the model. Ruling it out or finding something more exotic would force a rethink on how the universe is put together.
Scientists believe that in the first billionth of a second after the Big Bang, the universe was a gigantic soup of particles racing around at the speed of light without any mass to speak of. It was through their interaction with the Higgs field that they gained mass and eventually formed the universe.
The particle is theoretical, first posited in 1964 by six physicists, including Briton Peter Higgs.
The search for it only began in earnest in the 1980s, first in Fermilab’s now mothballed Tevatron particle collider near Chicago and later in a similar machine at CERN, but most intensively since 2010 with the start-up of the European centre’s Large Hadron Collider.
WHAT IS THE LARGE HADRON COLLIDER?
The Large Hadron Collider is the world’s biggest and most powerful particle accelerator, a 27-km (17-mile) looped pipe that sits in a tunnel 100 metres underground on the Swiss/French border. It cost 3 billion euros to build.
Two beams of protons are fired in opposite directions around it before smashing into each other to create many millions of particle collisions every second in a recreation of the conditions a fraction of a second after the Big Bang, when the Higgs field is believed to have ‘switched on’.
The vast amount of data produced is examined by banks of computers. Of all the trillions of collisions, very few are just right for revealing the Higgs particle. That makes the hunt for the Higgs slow, and progress incremental.
WHAT IS THE THRESHOLD FOR PROOF?
To claim a discovery, scientists have set themselves a target for certainty that they call “5 sigma”. This means that there is a probability of less than one in a million that their conclusions from the data harvested from the particle accelerator are the result of a statistical fluke.
The two teams hunting for the Higgs at CERN, called Atlas and CMS, now have twice the amount of data that allowed them to claim ‘tantalising glimpses’ of the Higgs at the end of last year and this could push their results beyond that threshold.
Watch the video above. Video courtesy: Gauri Narain
