Dark Matter Particles May Have Been Detected

During two seminars at Stanford and Fermilab on Thursday, researchers described signals for two events detected deep in an old iron mine in Minnesota that might mark the first detection of dark matter — or not. The presenters said the chances that the signals they detected were caused by something other than "neutralino" dark matter particles was 23 percent. "One source indicates that we'd need less than 10 total detections within the CDMS' range in order to have a high degree of confidence in the results." The NY Times describes the Cryogenic Dark Matter Search methodology: "The cryogenic experiment is nearly half a mile underground in an old iron mine in Soudan, Minn., to shield it from cosmic rays. It consists of a stack of germanium and silicon detectors, cooled to one-hundredth of a degree Kelvin. When a particle hits one of the detectors, it produces an electrical charge and deposits a small bit of energy in the form of heat, each of which are independently measured. By comparing the amounts of charge and heat left behind, the collaboration’s physicists can tell so-called wimps from more mundane particles like neutrons, which are expected to flood the underground chamber from radioactivity in the rocks around it." Here are the research team's summary notes of the latest results (PDF).

Comments

Re:It's the lack of energy, stupid!

[Colonel Korn]

So by reducing the temperature of the sensor to half a degree Kelvin, they have reduced the energy level of the sensor to almost nothing. Yes, it interacts with incoming particles, but it also radiates gravitational waves that could be misinterpreted as external particles. In essence, the detector is detecting itself.

Of course, there is a 23% chance I am completely wrong.

There's a 100% chance you're wrong. Gravitational waves can't be absorbed by these detectors in any meaningful way. To notice the effects of even massive gravitational waves you need a huge detector (like LIGO). Also, gravitational waves happen when a gravitational field changes. They propagate this change through the universe. Objects at rest aren't emitting gravitational waves.

If you isolated these sensors from the universe and let them sit for a long time, they wouldn't lose their mass to gravitational radiation - they'd probably sit around until death by baryon decay in 10^33 years.

And no, they're not detecting baryon decay either.