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

White male science

[Anonymous Coward]

As a 49 yo feminist grandmother, I reject these results, since they are done by an old boys network of grey haired caucasian scientists.

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

[garg0yle]

Something with no energy means it has no movement. No movement means it must radiate all of its energy as gravitation.

So, what you're saying is that something with no energy must lose all of its energy as gravitation. Anybody else see a problem with this explanation?

Re:It must be true!

[IndustrialComplex]

Because scientist's interpretation of what they see is never wrong! When did science start to feel more like religion to me...

So tell me where they went fairy tale on us here?

Here is just a gross simplification, so I may not be completely accurate, but I fail to see where this is fairy-tale science.

Characterization: Isn't that where we are finding that galaxies aren't behaving as we expect them to, and that behavior is in the form of gravitational interactions which shouldn't happen given the amount of mass which we can see.

Hypothesis:
There is something there which for some reason has a lot of mass, but we can't see it. Literally: Dark Matter

Deduction: If Dark Matter is weakly interacting as is suggested by the fact that we can't currently see it. If we are able to detect an interaction which cannot be accounted for among known particles, you have either discovered dark matter, or some other particle altogether if that detected particle is not massive enough when combined with the rate of interaction and the mass of the detected particle.

Experimentation:

Stick a detector way down in a mine shaft which will help filter out a lot of things which could cause a false positive. Look for interactions which do not match any known possible interactions.

Again, that is grossly simplified, but I don't see the jump in logic you are looking for.

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.

Re:Solar activity

[Mattskimo]

Flirt & Squirt 3?

Re:It must be true!

[Arancaytar]

Exactly! I keep telling people; Einstein was wrong! An absolute speed limit makes no sense because there's no way I can understand how that would work!

Do you have the email of the president of physics?