Experimental searches of neutrinoless double beta decay

TL;DR

This paper reviews current and upcoming experiments searching for neutrinoless double beta decay, highlighting their potential to reveal neutrino properties and the technical challenges involved.

Contribution

It provides a comprehensive review and comparison of experimental efforts and technological approaches in neutrinoless double beta decay searches.

Findings

Current experiments aim to cover the quasi-degenerate neutrino mass region.

Future projects need improved sensitivity to explore the inverted hierarchy.

Background reduction and technical innovations are crucial for advancing the field.

Abstract

Neutrinoless double decay is a unique probe for lepton number conservation and neutrino properties. It allows to investigate the Dirac/Majorana nature of the neutrinos and their absolute mass scale (hierarchy problem) with unprecedented sensitivity. A number of experiments are presently under preparation to cover the quasi-degenerate region of the neutrino mass spectrum. Improved sensitivities are however required to sound the so-called inverted hierarchy region. This is a real challenge faced by a number of new proposed projects, based either on large expansions of the present experiments or on new ideas top improve the technical performance or reduce the background contributions. A review of the most relevant ongoing experiments is given. The most relevant parameters contributing to the experimental sensitivity are discussed and a critical comparison of the future projects is proposed.