China Celebrates Non-Discovery of Dark Matter
A huge dark matter detector in China celebrated the publication of its first results: nothing.
You have to dig down into an article on PhysOrg to find out what happened. Featuring a big photo of the Chinese report about the initial findings from Panda-X, the country’s dark matter detector, the article buried the results near the bottom. For 12 paragraphs, the article talks about how big and wonderful the detector is:
PandaX is the first dark matter experiment in China that deploys more than one hundred kilograms of xenon as a detector; the project is designed to monitor potential collisions between xenon nucleons and weakly interactive massive particles, hypothesized candidates for dark matter.
This is followed by a discussion of theories about dark matter, and why weakly interactive massive particles (WIMPs) are prime candidates. Late in the article, after the reader has learned more than he or she may care to know about China’s entry into the world-wide search, and what methods different detectors use, comes the answer to the most interesting question, “What did they find?”
No dark matter signal was observed in the first PandaX-I run, which places strong constraints on all previously reported dark matter-like signals from other similar types of experiments.
The PandaX experiment to date has collected about 4 million raw events; only about ten thousand events fell into the energy region of interest for dark matter. In the quiet central part of the xenon target only 46 events were observed.
However, the data from these 46 events was consistent with signals marking background radiation, not dark matter.
Too bad. All that work for nothing. Again. “The scale of the PandaX-I experiment is second only to that of LUX, which is currently the planet’s largest dark matter experiment and is located in a South Dakota mine in the US.” America celebrated LUX’s non-detection of dark matter last year (see 10/30/13). Which country wants to be next?
The subdued placement of the results was not lost on readers, who left a lively trail of comments after the article.
Update 10/09/14: XMASS in October! The Kavli Foundation’s experiment published results of its search for warm WIMPs:
XMASS is a cryogenic detector using about 1 ton of liquid xenon as the target material. Using 165.9 days of data, a significant excess above the background is not observed in the fiducial mass of 41 kg. The absence of such a signal excludes the possibility that bosonic super-WIMPs constitute all dark matter in the universe.
Once again, the non-detection was buried near the end of the article after a lot of hype about the instrument.
OK, cosmologists, put up or shut up. Where is it? Don’t WIMP out on us after years of hype.
What will cosmologists do if observations deprive them of their favorite snake oil? If dark matter and dark energy turn out to be phantoms of their imaginations, how will anybody ever trust them again? These dark things are supposed to represent 96% of reality!
What does that imply about secular science’s grasp on reality?