Neutrinos are elementary particles that behave in ways that the standard theories of physics cannot properly explain. Anca Tureanu, the new professor of theoretical particle physics at the University of Helsinki, has developed her own alternative to an explanation that has prevailed for decades.
Neutrinos are extremely tiny elementary particles that are all around us. There are vast numbers of them - trillions pass through your body at this very moment - but they interact so weakly with other particles that they can only be detected with specialised instruments.
Despite their harmlessness, neutrinos pose a problem for our understanding of the universe, says , the new professor of particle physics at the University of Helsinki.
At the heart of the problem is a phenomenon called oscillation, in which a neutrino changes its type for no apparent reason.
There are three types, or so-called flavours, of neutrino: the electron neutrino, the muon neutrino and the tau neutrino, named according to which elementary particle reaction produces them.
Observations suggest, however, that neutrinos can change their flavour. According to Tureanu, this is a theoretical challenge.
- No other elementary particle changes its type while propagating freely, without interaction, she points out.
As a result, physicists developed a separate theory for neutrino conversions - one that essentially sits on top of the rest of particle physics.
Tureanu does not buy this theory.
- It has become true only because it has been repeated enough times. But it cannot even be proven.
Tureanu herself would explain the phenomenon differently. In her view, the vacuum should be understood as a medium in which neutrinos scatter, somewhat like light in the atmosphere.
Radical ideas from Kumpula
In the world of particle physics, Tureanu's idea is radical, and it is not yet widely accepted. This does not bother Tureanu: she has proposed ideas outside the mainstream before.
In her doctoral thesis and subsequent work, she put forward a novel concept of relativistic invariance for noncommutative quantum fields, where the order of mathematical variables matters: as if 2 × 3 were not the same as 3 × 2. The idea has attracted attention and could help us understand how gravity works at very small scales. Se has also challenged the CPT theorem, one of the fundamental theorems of physics, which describes the simultaneous symmetry of charge conjugation, mirror symmetry and time reversal.
The University of Helsinki has been a good home for radical ideas.
- No one here has ever told me what I should study or what I could publish, Tureanu says.
Tureanu has had a remarkably straightforward career for a modern physicist. She arrived at the University of Helsinki as an Erasmus exchange student in 1999 and became a doctoral researcher the following year. She has worked on the Kumpula campus ever since.
Tureanu's research requires no expensive instruments or field experiments. Most of the time, a pencil and squared (or any other kind of) paper are all she needs.
Although her day-to-day tasks have not changed much, the move from university lecturer to professor gives her ideas more weight and to herself more academic freedom.
- As soon as my professorship was confirmed, in which I proved in the most unequivocal manner why the standard approach to neutrino oscillations is a theoretical misconception and why we need not just an alternative theory, but a mathematically consistent one. This upfront challenge was so defiant that I wanted to do it only after securing my professorship.
