Nearly 100 years after Pauli’s initial theory, particle physicists still

have major unanswered questions about the fundamental properties of the

neutrino. These elusive particles hold many secrets, and studying them

gives us opportunities to discover Beyond the Standard Model (BSM)

physics. Detecting neutrinoless double beta decay (0νββ) will be proof

that neutrinos are Majorana fermions and will start to answer questions

about the origins of matter. Discovering sterile neutrinos could help iden-

tify the nature of dark matter, or explain the neutrino’s mass scale. nEXO

and the BeEST are both experiments that are designed to search for

answers to questions about the fundamental properties of the neutrino

through precision measurements of β decay. This presentation will describe

improvements to nEXO’s photodetector response analysis and the

search for a new BSM physics particle in the BeEST.