Why I care about neutrinos
To coincide with Sussex hosting the Institute of Physics' Joint HEPP and APP conference, 21-23 March 2016, Dr Simon Peeters, reader in experimental particle physics, explains how he became hooked on tiny sub-atomic particles that could hold the key to some of the mysteries of the Universe.
To me, the neutrino is the most amazing fundamental particle in particle physics. Despite being millions of times smaller than other sub-atomic particles, they could be the key to unravelling some of the deepest secrets of the Universe.
About 65 billion of them are produced by nuclear fusion in the Sun – they are what helps to make the Sun shine – but their ghostlike properties means they can pass through the Earth seemingly without touching other particles.
I became hooked on trying to understand them after studying particle physics at university.At the end of my studies I worked at the Large Hadron Collider at CERN for nearly two years, which was an amazing experience. My PhD thesis was on the design of a (small) part of the huge ATLAS detector and how we could use this machine to find the Higgs boson. But this was a few years before the LHC would be turned on.
I joined the Sudbury Neutrino Observatory in 2003, shortly after the lab’s discovery that neutrinos have mass. The findings, which led to SNO receiving the Nobel prize in 2015, was a major step forward in our understanding of something that had puzzled physicists for decades. It was thought that neutrinos were without mass. But the experiment, led by Art McDonald, found that neutrinos were able to oscillate and change their identity.
Neutrino oscillations could potentially answer one of the really big questions in modern science: Why is there more matter than anti-matter in the Universe? To answer this, we need to understand the neutrino oscillations even better than we do now and also to better understand what a neutrino particle actually is.
The details of the small determine how the very large works, which continues to fascinate me. Since the success of SNO, the facility has been expanded and is now called SNOLAB: A 1000 square metre clean room, located in an operational nickel mine two kilometres underground in Ontario, Canada, and filled with the most advanced tools to study neutrinos and dark matter. I visited it again last week, still trying to figure out how stuff works.