Optimal Particle identification Of Single Site events with Underground MKIDs detectors

Introduction

The observation of neutrinoless double-beta decay (0νββ) would revolutionize our understanding of neutrinos by affirming their Majorana nature and shedding light on their absolute mass scale and hierarchy. Detecting its monochromatic peak at MeV levels, with half-lives over 10^26 years, is a significant challenge.

Experimental Challenges

Scientists are striving to push the scale of experimental exposures to tons of material per year. It is only in a background-free experiment that sensitivity scales linearly with exposure, maximizing the benefits of increased detector mass. The forefront of this search lies with ton-scale arrays of bolometers at mK temperatures, such as CUORE, which investigates 0νββ in 130Te using TeO2 crystals. These crystals are known for their exceptional energy resolution but are plagued by background event identification challenges.

Leading Candidates

With its 34% isotopic abundance, 130Te emerges as the leading 0νββ candidate, bypassing the need for the now-challenged enrichment process.

OPOSSUM Innovation

OPOSSUM will revolutionize event detection by outfitting 12 CUORE crystals with six quantum-limited sensors (Microwave Kinetic Inductance Detectors) and a thermistor. This innovative approach will enable discrimination of events by classifying them as Single Site or Multi Site Events.

Pulse-Shape Analysis

Through pulse-shape analysis, OPOSSUM is set to tag 0νββ signals with 3σ distinction from any background. This method has the potential to lower CUORE's background from 10^-2 to below 10^-4 counts/keV/kg/year.

Deployment and Impact

The success of OPOSSUM will facilitate rapid deployment within the existing setup without extensive R&D or major financial outlay. OPOSSUM-1ton is poised to become the first bolometric ton-scale, background-free experiment that can aim at surpassing the inverted hierarchy scenario, i.e., <10 meV Majorana mass.

Expertise Contribution

My vast experimental knowledge in low-temperature detectors is crucial for OPOSSUM's mission to push the boundaries of particle physics as per the EU Astroparticle committee recommendation for the neutrino physics programme.