Tag Archives: WIMPS

Physicists look for new alternatives to explain dark matter

The uncertainty of science: Having failed to detect WIMPs, their primary dark matter suspect, physicists are now looking at new and different candidates that might explain dark matter, and the new leading candidate is something called SIMPs.

The intensive, worldwide search for dark matter, the missing mass in the universe, has so far failed to find an abundance of dark, massive stars or scads of strange new weakly interacting particles (WIMPs), but a new candidate is slowly gaining followers and observational support.

Called SIMPs – strongly interacting massive particles – they were proposed three years ago by UC Berkeley theoretical physicist Hitoshi Murayama, a professor of physics and director of the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) in Japan, and former UC Berkeley postdoc Yonit Hochberg, now at Hebrew University in Israel.

Murayama says that recent observations of a nearby galactic pile-up could be evidence for the existence of SIMPs, and he anticipates that future particle physics experiments will discover one of them.

We shall see. The mystery remains, that we do not understand why most galaxies do not fly apart because their outer stars simply move too fast. Since all searches for ordinary matter have come up well short, dark matter remains the simplest explanation, though it still reminds me the theories of ether that once dominated physics, and never existed.


A new dark matter detector has failed to detect any dark matter after its first three months of operation.

The uncertainty of science: A new dark matter detector has failed to detect any dark matter after its first three months of operation.

Buried about a mile underground in a repurposed South Dakota gold mine, the LUX experiment searches for signs of dark matter particles colliding with the atoms in a vat of liquid xenon. During its first three months of operation, the detector found no such signals whatsoever. “We looked hard for these dark matter particles and we didn’t see anything,” says physicist Rick Gaitskell of Brown University, co-spokesperson for the LUX experiment. The results, presented at a seminar today and submitted to Physical Review Letters for publication, rule out a number of possible masses and characteristics for the particles that make up dark matter. The null result also conflicts with earlier experiments that had reported possible signals of dark matter.

This experiment has not proven that dark matter does not exist. It merely has narrowed significantly the kinds of particles that dark matter could be made of. That the results also contradict evidence from other detectors, however, leaves this specific area of science particularly uncertain.


Experiment fails to find dark matter

The uncertainty of science: An underground experiment in Italy has failed to detect dark matter, as theorized by scientists.

In a paper published online last night, the XENON100 researchers report three events detected during a 100-day run of the experiment last year that might have been due to dark matter1. However, as they expected to see between 1.2 and 2.4 background events — interactions mostly caused by a radioactive contaminant in the xenon — their result is statistically negative and therefore rules out the existence of many of the more strongly interacting and heavier WIMPs.