The SNO+ experiment physics goals and background mitigation

Abstract: The main physics goal of the SNO+ experiment is the search for neutrinoless double-beta decay (0$\nu\beta\beta$), a rare process which if detected, will prove the Majorana nature of neutrinos and provide information on the absolute scale of the neutrino mass. Additional physics goals include the study of solar neutrinos, anti-neutrinos from nuclear reactors and the Earth's natural radioactivity as well as Supernovae neutrinos. Located in the SNOLAB (Canada) deep underground laboratory, it will re-use the SNO detector. A short phase with the detector completely filled with water has started at the beginning of 2017, before running the detector with scintillator. This paper describes in details the SNO+ sensitivity to 0$\nu\beta\beta$ decays, as well as the other physics goals. Crucial to these large volume liquid scintillator experiments, is the ability to constraint the low-energy background from radioactive decays. Methods to mitigate those are also presented.