Dark matter no-show at sensitive underground lab
17:52 14 April 2011
Celeste Biever, deputy news editor
Photosensor arrays meant to capture light produced when dark matter particles interact with xenon atoms (Image: Xenon Collaboration)
It's just like a wimp to be a no-show when summoned for interrogation. That seems to be the result of an experiment to detect the weakly interacting massive particles, or WIMPs, thought to make up elusive dark matter that is thought to make up much of the mass of the universe.
After 100 days of monitoring, a tub of cryogenically chilled liquid xenon deep in an Italian mountain has shown no trace of the particles it is designed to catch. The result doesn't rule out the existence of WIMPs, but it does seem these particles are slipperier than previously hoped.
The Xenon100 experiment, at the Gran Sasso National Laboratory near L'Aquila, Italy, is one of the most sensitive dark matter detectors in the world. The results of the 100-day trial were hotly anticipated.
"It's like being at a wedding waiting for the bride," one nervous team member said before they were announced, according to Science News.
Dark matter is needed to explain where the gravity comes from that stops spinning galaxies from flying apart. It is thought to make up about 83 per cent of the universe but what it is actually made of is one of the biggest mysteries in physics.
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Read more here: New Scientist
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Dark Matter Results from 100 Live Days of XENON100 Data
XENON100 Collaboration: E. Aprile et al.
(Submitted on 13 Apr 2011)
Abstract
We present results from the direct search for dark matter with the XENON100 detector, installed underground at the Laboratori Nazionali del Gran Sasso of INFN, Italy. XENON100 is a two-phase time projection chamber with a 62 kg liquid xenon target. Interaction vertex reconstruction in three dimensions with millimeter precision allows to select only the innermost 48 kg as ultra-low background fiducial target. In 100.9 live days of data, acquired between January and June 2010, no evidence for dark matter is found. Three candidate events were observed in a pre-defined signal region with an expected background of 1.8 +/- 0.6 events. This leads to the most stringent limit on dark matter interactions today, excluding spin-independent elastic WIMP-nucleon scattering cross-sections above 7.0x10^-45 cm^2 for a WIMP mass of 50 GeV/c^2 at 90% confidence level.
Comments: 5 pages, 5 figures
Subjects: Cosmology and Extragalactic Astrophysics (astro-ph.CO); High Energy Physics - Experiment (hep-ex)
Cite as: arXiv:1104.2549v1 [astro-ph.CO]
Submission historyFrom: Rafael Florian Lang [view email]
[v1] Wed, 13 Apr 2011 17:02:49 GMT (1453kb,D)
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