Double Beta and Dark Matter Search - Window to New Physics beyond the Standard Model of Particle Physics

TL;DR

This paper reviews the potential of double beta decay experiments to explore physics beyond the Standard Model, presenting recent results, theoretical implications, and proposing the GENIUS experiment to vastly improve sensitivity to neutrino masses and dark matter detection.

Contribution

It introduces the GENIUS experiment concept, aiming to significantly enhance sensitivity to Majorana neutrino masses and dark matter, building on recent experimental and theoretical advancements.

Findings

Heidelberg-Moscow experiment probes electron mass below 0.1 eV.

Current experiments set stringent limits on cold dark matter (WIMPs).

GENIUS could reach neutrino mass sensitivities down to 0.001 eV.

Abstract

Nuclear double beta decay provides an extraordinarily broad potential to search for beyond Standard Model physics, probing already now the TeV scale, on which new physics should manifest itself. These possibilities are reviewed here. First, the results of present generation experiments are presented. The most sensitive one of them - the Heidelberg-Moscow experiment in the Gran Sasso - probes the electron mass now in the sub eV region and will reach a limit of $\sim$ 0.1 eV in a few years. Basing to a large extent on the theoretical work of the Heidelberg Double Beta Group in the last two years, results are obtained also for SUSY models (R-parity breaking, sneutrino mass), leptoquarks (leptoquark-Higgs coupling), compositeness, right-handed W boson mass, test of special relativity and equivalence principle in the neutrino sector and others. One of the enriched $^{76}$Ge detectors also yields the most stringent limits for cold dark matter (WIMPs) to date by using raw data. A new Heidelberg experimental proposal (GENIUS) is described which would allow to increase the sensitivity for Majorana neutrino masses from the present level of at best 0.1 eV down to 0.01 or even 0.001 eV. It would further, already in a first step using only 100 kg of natural Ge detectors, cover almost the full MSSM parameter space for prediction of neutralinos as cold dark matter.