Physicists have proposed that ‘neutrinos’ – one of the most abundant fundamental particles in the universe – could be the origin of all matter in the universe today.

However, despite their abundance, neutrinos are some of the most elusive particles to detect and, after decades of research, physicists still have many questions about their make-up, properties, and role in the universe’s origin.

At the University of Glasgow, research by members of the particle physics group uses data from the most sensitive neutrino detector on Earth, the T2K (Tokai-to-Kamioka) experiment in Japan. The main goal of the T2K experiment is addressing one of the greatest outstanding problems of modern physics, namely that our current models of the composition of the universe have a fundamental gap.

Modern physics observes particles (such as electrons) and antiparticles (like positrons) which form a symmetric pair where each has an identical mass but opposite charge. However, we now know that for every antiparticle there are in fact approximately ten billion particles, meaning the universe has a perfect symmetry with each particle balanced by an antiparticle with identical mass but opposite charge, and an almost perfect asymmetry, due to there being many, many more particles than antiparticles in the universe. This naturally leads to the question: where does this asymmetry stem from?

One way to investigate this phenomenon is through studying neutrinos. These fundamental neutral particles can be created in a state of quantum superposition – for example, the ability to be in multiple states at the same time – wherein they change their state in what is known as ‘neutrino oscillation’. By counting how often this change occurs, it may illuminate the underlying mechanism giving rise to the observed particle/antiparticle asymmetry. ...continue reading