Title: Extending the CRESST-II commissioning run limits to lower masses Authors: Andrew Brown, Sam Henry, Hans Kraus, Christopher McCabe
Motivated by the recent interest in light WIMPs of mass ~O(10 GeV), an extension of the elastic, spin-independent WIMP-nucleon cross-section limits resulting from the CRESST-II commissioning run (2007) are presented. Previously, these data were used to set cross-section limits from 1000 GeV down to ~17 GeV, using tungsten recoils, in 47.9 kg-days of exposure of calcium tungstate. Here, the overlap of the oxygen and calcium bands with the acceptance region of the commissioning run data set is reconstructed using previously published quenching factors. The resulting elastic WIMP cross section limits, accounting for the additional exposure of oxygen and calcium, are presented down to 5 GeV.
A third experiment has detected tantalising signs of dark matter. The finding raises more questions than answers, however, as two other experiments have found no sign of the mysterious stuff, which is thought to create the gravity that holds spinning galaxies together, accounting for about 85 per cent of all matter in the universe. The new result comes from an experiment called CRESST II, which uses a few dozen supercooled calcium tungstate crystals to hunt for dark matter from deep beneath the Gran Sasso mountain in Italy. When a particle hits one of the crystals, the crystal gives off a pulse of light, and sensitive thermometers gauge the energy of the collision. Read more
Scientists may have seen more hints of the dark matter purported to make up a majority of the mass in the Universe. Researchers at the Cresst experiment in Italy say they have spotted 67 events in their detectors that may be caused by dark matter particles called Wimps. The finds must be reconciled with other experiments that have recently hinted at the detection of Wimps Read more
A chance discovery by cosmologists searching for dark matter - the elusive stuff thought to make up most of the mass in the universe - could lead to the development of an ultra-sensitive probe that can spot cracks in materials opening up, even when they're only a few atoms long.
Dark matter detectors at the Cryogenic Rare Event Search using Superconducting Thermometers (CRESST) underground laboratory at Gran Sasso, Italy, were being put through preliminary tests in 1999 when they began recording thousands of times more signals than expected.
"We were very disturbed. The set-up is so sensitive that touching it with bare hands can cause problems. At first, we could only think some idiot had handled it." - Leo Stodolsky, team member at the Max Planck Institute for Physics in Munich, Germany.
The detectors consists of a cryogenically cooled sapphire crystal and a superconducting thermometer.