Dark matter


It is a remarkable fact that we do not know what the vast majority of the Universe is made of. Everything we can see, planets, stars, galaxies and gas, makes up just a tiny fraction of the matter in the Universe. The rest, invisible to us, was dubbed ‘dark matter‘ by Fritz Zwicky, the maverick but brilliant astronomer, rocket scientist and humanitarian, who inferred its existence when trying to reconcile the motions of galaxies with the laws of gravity. A vast array of more recent astronomical observations, probing the Universe at many different scales and wavelengths, all point to the same conclusion. Now, some 80 years later, dark matter, and its partner dark energy, are the pervasive dogma of cosmology. At the other extreme of scale, we have a similar mystery, in that Nature has presented us with a range of particles with a great range of properties, yet we know little of why there should be such diversity. The theories such as supersymmetry may provide some of the answers.  One of their most robust predictions is that of a new fundamental particle, produced in abundance in the aftermath of the big bang, and which it will be hard, but not quite impossible to detect. It is not surprising therefore that the search for these elusive particles, with the fundamental impact across both physics and astronomy that its detection would bring, has become one of the most prized of all goals in science...

one of the greatest challenges of modern physics

LUX, the Large Underground Xenon experiment, is just starting operations at the Homestake mine in South Dakota. With 350 litres of liquid xenon, this is the world’s leading direct dark matter search instrument.

DRIFT-II is the world’s leading dark matter search instrument with directional sensitivity. The use of low pressure gas allows nuclear recoils to generate tracks of measurable length.

ZEPLIN-III, one of the world’s leading direct search instruments, recently completed its science operations at the Boulby mine in the North East of England. It pioneered the use of high fields to deliver improved discrimination against backgrounds.

DMUK - all the UK’s dark matter experimentalists have joined forces, looking to develop a coherent strategy for future UK leadership of the field.

LUX-ZEPLIN (LZ) - Scheduled to begin construction in 2014, the merged LUX and ZEPLIN collaborations will build a 9 tonne two phase liquid xenon TPC (7 tonnes fiducial) that will have sensitivity sufficient to probe an enormous depth of parameter space for WIMPs.