A large scale double beta and dark matter experiment: GENIUS

Abstract

The recent results from the HEIDELBERG-MOSCOW experiment have demonstrated the large potential of double beta decay to search for new physics beyond the Standard Model. To increase by a major step the present sensitivity for double beta decay and dark matter search much bigger source strengths and much lower backgrounds are needed than used in experiments under operation at present or under construction. We present here a study of a project proposed recently [1], which would operate one ton of 'naked' enriched GErmanium-detectors in liquid NItrogen as shielding in an Underground Setup (GENIUS). It improves the sensitivity to neutrino masses to 0.01 eV. A ten ton version would probe neutrino masses even down to 10 −3 eV. The first version would allow to test the atmospheric neutrino problem, the second at least part of the solar neutrino problem. Both versions would allow in addition significant contributions to testing several classes of GUT models. These are especially tests of R-parity breaking supersymmetry models, leptoquark masses and mechanism and right-handed W-boson masses comparable to LHC. The second issue of the experiment is the search for dark matter in the universe. The entire MSSM parameter space for prediction of neutralinos as dark matter particles could be covered already in a first step of the full experiment with the same purity requirements, but using only 100 kg of 76 Ge or even of natural Ge making the experiment competitive to LHC in the search for supersymmetry.The layout of the proposed experiment is discussed and the shielding and purity requirements are studied using GEANT Monte Carlo simulations. As a demonstration of the feasibility of the experiment first results of operating a 'naked' Ge detector in liquid nitrogen are presented.

Neutrinoless Double Beta Decay Potential in a Large Mixing Angle World

“…We are entering an exciting decade. [10] experiment as well as the expected sensitivities for the CUORE [11], MOON [12], EXO [13] proposals and the 1 ton and 10 ton proposal of GENIUS [14].…”

“…Future experiments such as CUORE [11], MOON [12] and EXO [13] and GE-NIUS [14] aim at sensitivities down to 10 −2 -10 −3 eV. The observable measured in the mass mechanism of 0νββ decay is the ee element of the neutrino mass matrix in flavor space, the effective neutrino mass…”

Double beta decay—Physics beyond the standard model now, and in future (GENIUS)

“…12 that none of the present experimental approaches, or plans or even vague ideas has a chance to surpass the border of 0.1 eV for the neutrino mass to lower values (see also [Nor97]). At present there is only one way visible to reach the domain of lower neutrino masses, suggested by the author of this report and meanwhile investigated in some detail concerning its experimental realization and and physics potential in [Kla97d,Hel97].…”

“…The cost of the project would be a minor fraction of detectors prepared for LHC physics as CMS or ATLAS. We give in the next two subsections some results of Monte Carlo simulations of the setup [Hel97] and some estimates of the physics potential [Kla97d]. Fig.…”

“…Figs. 17, 18 show the results of Monte Carlo simulations, using the CERN GEANT code, of the background [Hel97], starting from purity levels of the nitrogen being in general an order of magnitude less stringent than those already achieved in the CTF for the BOREXINO experiment. The influence of muons penetrating the Gran Sasso rock on the background can be reduced comfortably through coincidences between the Germanium detectors from the muon induced showers.…”