The Search for Neutrinoless Double Beta Decay with ¹³⁰Te with CUORE-0

This thesis describes the design, operation and results of an experimental search for neutrinoless double beta decay (0νββ) of ¹³⁰Te using the CUORE-0 detector. The discovery of 0νββ would have profound implications for particle physics and our understanding of the Universe. Its discovery would demonstrate the violation of lepton number and imply that neutrinos are Majorana fermions and therefore their own anti-particles. Combined with other experimental results, the discovery of 0νββ could also have implications for understanding the absolute neutrino mass scale as well as the presently unknown neutrino mass hierarchy. The CUORE experiment is a ton-scale search for 0νββ in ¹³⁰Te expected to begin operation in late 2015. The first stage of this experiment is a smaller 39-kg active-mass detector called CUORE-0. This detector contains 11 kg of ¹³⁰Te and operates in the Laboratori Nazionali del Gran Sasso lab in Italy from 2013-2015. The results presented here are based on a ^natTeO₂ exposure of 35.2 kg·yr, or 9.8 kg·yr exposure of ¹³⁰Te collected between 2013-2015. We see no evidence of 0νββ and place an upper limit on the 0νββ decay rate of Γ_0νββ<0.25x10²⁴ yr¹ (90 % C.L.), corresponding to a lower limit on the half-life of T_1/2^0ν>2.8x10²⁴ yr (90 % C.L.). We combine the present result with the results of previous searches in ¹³⁰Te. Combining it with the 1.2 kg·Te exposure from the Three Towers Test run we place a half-life limit of T_1/2⁰³ν>3.3x10²⁴ yr (90 % C.L.). And combining these results with the 19.75 kg·yr ¹³⁰Te exposure from Cuoricino, we place the strongest limit on the 0νββ half-life of ¹³⁰Te to date, at T_1/2^0ν>4.5x10²⁴ yr (90 % C.L.). Using the present nuclear matrix element calculations for ¹³⁰Te, this result corresponds to a 90 % upper limit range on the effective Majorana mass of m_ββ<250-710 meV.