Albert Einstein Center for Fundamental Physics
The group has moved to the University of Freiburg, Germany, in fall 2016. You can find our new pages here.
The ultimate dark matter detector:
Dark matter experiments with target masses at the ton scale are alreday reality. Our group participates in XENON1T which currently commissions a detector filled with about 3.5 tons of liquid xenon, of which about 1 ton will be used for analysis.
In case of a positive dark matter detection in this detector - or its upgrade phase XENONnT with more than 3x the mass - a larger instrument will be required in order to study the properties of the dark matter particle. If nothing is found, these larger detectors will be needed as well in order to fully explore the predicted parameter space for WIMP dark matter in order to either detect it at even lower cross sections or to constrain it even further. The ultimate threshold for WIMP searches is at spin-independent WIMP-nucleon scattering cross sections of a few 10-49 cm2, where coherent neutrino interactions with atomic nuclei become the dominating background and which cannot be shielded.
In order to have the technology ready when it becomes necessary to build these detectors, the DARWIN project was initiated. The project combines the expertise of many experimental physicists working with liquid xenon to detect dark matter. The DARWIN goal is to eventually build the ultimate WIMP detector with a target mass of 40 tons of liquid xenon. The inner 30 tons will be used for analysis as these have the lowest radioactive background.
A detector of this size will be limited by background from neutrinos which, however, are also an interesting physics case itself. Typical neutrino experiment has much higher thresholds but DARWIN could directly measure low energetic solar neutrinos (pp, 7Be).
The Bern group concentrates on the following topics:
DARWIN is an international consortium of about 100 people. It combines ample expertise on dark matter search with liquid xenon, from neutrino and high energy physics, and with backgrounds from extremely low backgrounds to particle physics theory.