WIMP detector finds nothing

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The uncertainty of science: A detector buried a mile underground so that it could only detect the predicted Weak Interacting Massive Particles (WIMP) thought to comprise dark matter has found nothing

Dark matter is thought to account for more than four-fifths of the mass in the universe. Scientists are confident of its existence because the effects of its gravity can be seen in the rotation of galaxies and in the way light bends as it travels through the universe, but experiments have yet to make direct contact with a dark matter particle. The LUX experiment was designed to look for weakly interacting massive particles, or WIMPs, the leading theoretical candidate for a dark matter particle. If the WIMP idea is correct, billions of these particles pass through your hand every second, and also through the Earth and everything on it. But because WIMPs interact so weakly with ordinary matter, this ghostly traverse goes entirely unnoticed.

…“We worked hard and stayed vigilant over more than a year and a half to keep the detector running in optimal conditions and maximize useful data time,” said Simon Fiorucci, a physicist at Berkeley Lab and Science Coordination Manager for the experiment. “The result is unambiguous data we can be proud of and a timely result in this very competitive field—even if it is not the positive detection we were all hoping for.”

This null result, which has its own uncertainties that require confirmation by another experimental test, places significant constraints on the possible nature of the dark matter particle, assuming it exists. And if confirmed, this result makes the hunt to explain the gravitational data of galaxy rotation, something that has been confirmed repeatedly, far more difficult.


  • Joe

    Robert, I am sorry, but reading the linked article, I had the strangest feeling that I was watching a Monty Python skit, they don’t know what it is or what it looks like, yet they created a detector for it, and are surprised they got nothing.

  • As Robert points out, a null result isn’t necessarily a negative result. My understanding is that the experiment was a first (and expensive) approximation of parameters for WIMP detection. Guided by our best theories (guesses), Joe is correct in pointing out that the experimenters didn’t really know what to test for. But they now have a better idea of what not to look for, and future experiments can explore other parameters.

    The observational data is irrefutable, but I’m still skeptical of the ‘here be dragons’ approach because we don’t understand what’s going on. I trust that cosmologists and experimental physicists will keep Occam’s razor close to hand.

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