Modelling and reconstruction of events in SNO+ related to future searches for lepton and baryon number violation

Thesis

SNO+ is a liquid scintillator experiment whose physics goals include measurements of solar neutrinos, reactor anti-neutrinos, geo neutrinos and double beta decay. During an initial water phase, it will also search for invisible modes of nucleon decay.

This thesis investigates methods of improving the detector's sensitivity to the baryon and lepton violating processes of neutrinoless double beta decay and invisible nucleon decay. It does this through an improved scintillator model, allowing the sensitivity of the detector with different loading techniques to be evaluated, through a new background rejection technique, capable of increasing the active volume of the detector, and with the development of improved position fitters, achieving resolutions of approximately 10 cm in scintillator and 25 cm in water.

The sensitivity of SNO+ to invisible modes of nucleon decay is explored, predicting, after one month of data, a limit of τ > 1.38 x 10³⁰ years on the decay of neutrons and of τ > 1.57 x 10³⁰ years on the decay of protons.

Authors: Coulter, IT

• Publication date: 2013
• DOI: 10.5287/ora-kovy4jrob
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: proton decay; neutrino; neutrinoless double beta decay; nucleon decay; SNO+
• Subjects: Physics; Particle physics