Anthony Au is a PhD student in the Department of Physics, King’s College London under the supervision of Professor Jeanne Wilson. Born and raised in Hong Kong, Anthony obtained both his BSc and MPhil at The Hong Kong University of Science and Technology before coming to King’s to pursue his PhD. His master’s research is in computational neutrino cosmology where he modeled the effects of the massive Cosmic Neutrino Background on the formation of Large-Scale Structures with computer simulations.

For his PhD studies, Anthony has shifted focus to particle physics and will be joining the SNO+ collaboration. The SNO+ experiment is a multipurpose neutrino detector located at SNOLAB. Its primary objective to search for neutrino-less double beta decay, a process that would prove the Majorana nature of neutrinos. If found, the neutrino would be the only Majorana fermion in Standard Model of Particle Physics.

Research Interests

• Neutrinos
• Particle Physics
• Cosmology
• Dark Matter

Neutrinos are elusive particles that are currently not well understood. They are small, light, electrically neutral particles which only interact via the Weak Interaction, making them difficult to perform experiments on. Neutrino oscillations, where a neutrino changes its flavor as it propagates in space, imply that neutrinos have mass. The origin of this mass is not known, but a popular theory proposes that neutrinos gain mass through the Majorana mechanism. This in turn implies the possibility of neutrino-less double beta decay, a process being searched for at SNO+. There are other methods to study neutrinos, such as inferring neutrino mass from the CMB power spectrum in cosmology, or direct beta decay measurements in particle physics. A more complete understanding of neutrinos can be developed through these different approaches.

Thesis title and abstract

Search for Neutrino-less Double Beta Decay with the SNO+ Experiment

SNO+ is an underground liquid scintillator neutrino detector at SNOLAB in Sudbury, Canada, mainly used to search for neutrino-less double beta decay in Tellurium-130. This process only occurs if the neutrino is a Majorana particle, where a neutrino is the same as the anti-neutrino, and has yet to be detected. As the reaction rate is proportional to the neutrino mass, which is known to extremely small, neutrino-less double beta decay is a rare process. To identify the process at SNO+, analysis techniques must be developed to quantify and characterise the reactions which are not of interest known as backgrounds. There are many sources of backgrounds ranging from cosmic rays to signals from the scintillator itself. Through a combination of quality assessment of the hardware and developing software to analyse scintillator data, this project aims to contribute to understand the nature of neutrinos at SNO+.