Today, the team behind one of the most sensitive dark matter detectors announced its full experimental run had failed to turn up any of the particles it was looking for. The new research result is also described with further details on the LUX Collaboration’s website.
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Despite working on the world’s most sensitive dark matter experiment, scientists did not detect any sign of the world’s most mysterious substance. Scientists named it dark matter as it did not seem to emit any light.
The final performance over the 20 months ran with four times the sensitivity scientists had originally expected.
“We’ve probed previously unexplored regions of parameter space with the aim of making the first definitive discovery of dark matter”, Cham Ghag, a physicist at University College London and collaborator on LUX, said in another statement. “However, what we have observed is consistent with background alone”, Gaitskell added. “Many theorists think that the dark matter mass will be high, around a thousand times the mass of a proton”.
LUX scientists will be pouring over the data over the next few months, analyzing it to help shape future experiments and maximize the chance of detecting the elusive dark matter particle.
Their WIMP detector consisted of a tank of cooled liquid xenon that was surrounded by sensors to measure tiny flashes of light caused by dark matter particles colliding with xenon atoms.
“It would have been marvelous if the improved sensitivity had also delivered a clear dark-matter signal”, Gaitskell said. Those particles are 10 to 100 times the mass of a proton, but interact only very weakly with ordinary matter (which is why scientists can not easily detect them).
However, researchers had hoped to detect their rare collisions with LUX’s detector material-a third of a ton of liquid xenon.
To shield against cosmic rays, the tank of xenon was inside a 72,000-gallon tank of ultra-pure water. For three years scientists have been looking for dark matter almost a mile underground. But while it provides limits, LUX isn’t able to rule them out entirely. “We then used our findings to determine how efficient the detector is, and found that if a dark matter particle had hit the detector, we would have identified it”.
The results do not disprove the WIMP model, but they exclude many potential models for dark matter particles and offer a guideline for the next generation of detector experiments.
But the fact that nothing was found doesn’t mean the experiment wasn’t a success, said scientists.
For now, the hunt for WIMPS moves to the Large Hadron Collider (LHC) at CERN in Geneva, the world’s most-powerful atom smasher.
A new Wimp hunting experiment, Lux-Zeplin (LZ), is due to replace Lux at the Sanford Underground Research Facility.
“The innovations of the LUX experiment form the foundation for the LZ experiment”, said Harry Nelson, University of California, Santa Barbara, and spokesperson for LZ. However, there is a new Lux detector being developed. “LZ should be online in 2020”.
The university and a number of its researchers have been working on the Lux project since 2012. A South Dakota-owned facility, it is managed by the SDSTA, which reopened the mine in 2007 with $40 million in funding from the South Dakota State Legislature and a $70 million donation from philanthropist T. Denny Sanford. The U.S. Department of Energy (DOE) supports Sanford Lab’s operations. “We’re proud to support the LUX collaboration and congratulate them on reaching this higher level of sensitivity”, said Mike Headley, executive director of the SDSTA. Over the years it grew from a detector that included parts bought for a few bucks on eBay into a major project involving researchers from 20 universities and national labs in the United States, the UK and Portugal. “Richard Gaitskell told us”.
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Major support for LUX came from the DOE Office of Science.
