Search for Double Beta Plus Decays with NuDoubt++

TL;DR

NuDoubt++ introduces a novel hybrid liquid scintillator detector to search for double beta plus decays, aiming to detect Standard Model modes and constrain exotic neutrinoless processes with improved background rejection.

Contribution

The paper presents a new detector concept combining advanced scintillator technologies for enhanced detection of double beta plus decays, including prototype design and sensitivity estimates.

Findings

Prototype layout demonstrated feasibility of the detector concept.

Expected sensitivities indicate potential to observe Standard Model modes.

Improved background rejection enhances search for exotic decay processes.

Abstract

The NuDoubt++ experiment proposes a novel detector concept to search for double beta plus decays using a hybrid opaque liquid scintillator. This design combines recent advances in scintillator technologies (namely, slow and opaque media, and optimized wavelength-shifting fibers coupled to silicon photomultipliers) to achieve improved particle identification and background rejection. We present the physics motivations, detector design, first prototype layout, and expected sensitivities for both standard and exotic modes, using 78Kr as an initial target isotope. With this approach, NuDoubt++ aims to make the first observation of positron emitting Standard Model two-neutrino modes and improve current constraints on Beyond Standard Model neutrinoless processes.