Supercomputers provide new window into the life and death of the neutron

Experiments that measure the lifetime of neutrons reveal a perplexing and unresolved discrepancy. While this lifetime has been measured to a precision within 1 percent using different techniques, apparent conflicts in the measurements offer the exciting possibility of learning about as-yet undiscovered physics. Now, a team of scientists including Dr Chris Bouchard in the School of Physics & Astronomy has enlisted powerful supercomputers to calculate a quantity known as the "nucleon axial coupling," or gA - which is central to our understanding of a neutron's lifetime - with unprecedented precision. The method offers a clear path to further improvements that may help to resolve the experimental discrepancy. To achieve their results, the researchers created a microscopic slice of spacetime, embedded with the laws from the Standard Model of particle physics, to provide a window into the subatomic world. Their study was published online 7 June . The nucleon axial coupling is defined as the strength at which one component (known as the axial component) of the "weak current" of the Standard Model of particle physics couples to the neutron.