Our university’s physicists find out what matters most

A team of physicists from Paisley’s university have discovered an element that could hold the key to the mystery around why there is much more matter than antimatter in the Universe.

The University of the West of Scotland and University of Strathclyde academics have discovered that one of the isotopes of the element thorium possesses the most pear-shaped nucleus yet to be discovered.

Nuclei similar to thorium-228 may now be able to be used to perform new tests to try find the answer to the mystery surrounding matter and antimatter.

UWS’s Dr David O’Donnell, who led the project, said:“Our research shows that, with good ideas, world-leading nuclear physics experiments can be performed in university laboratories.

“This work augments the experiments which nuclear physicists at UWS are leading at large experimental facilities around the world. Being able to perform experiments like this one provides excellent training for our students.”

Physics explains that the Universe is composed of fundamental particles such as the electrons which are found in every atom.

The Standard Model, the best theory physicists have to describe the sub-atomic properties of all the matter in the Universe, predicts that each fundamental particle can have a similar antiparticle.

Collectively the antiparticles, which are almost identical to their matter counterparts except they carry opposite charge, are known as antimatter.

The experiments began with a sample of thorium-232, which has a half-life of 14 billion years, meaning it decays very slowly.

The decay chain of this nucleus creates excited quantum mechanical states of the nucleus thorium-228. Such states decay within nanoseconds of being created, by emitting gamma rays.

Dr O’Donnell and his team used highly sensitive state-of-the-art scintillator detectors to detect these ultra-rare and fast decays.

With careful configuration of detectors and signal-processing electronics, the research team have been able to precisely measure the lifetime of the excited quantum states, with an accuracy of two trillionths of a second.

The shorter the lifetime of the quantum state the more pronounced the pear shape of the thorium-228 nucleus – giving researchers a better chance of finding an EDM.

The research paper can be read in full in Nature Physics.