Dark business with dark matter

Experiments in underground laboratories on the search for particles of dark matter continue to issue results and sometimes excite the audience.

Recall that until now the Dama/Libra collaboration (Grand Sasso laboratory) continues to insist that he sees the signal, although these results are in contradiction with the data of other experiments (the contradictions in principle is permitted in some models, but it looks like some tricks AD HOC).

The latest results of this collaboration are presented in the ARXIV E-Print: 0912.0660.

In early December, rumors began to appear that the CDMS II collaboration conducting an experiment in an underground laboratory in the Sudan mine in Minnesota, preparing an article with a positive result.

Almost immediately after the appearance of these rumors, E-prints appeared from the collaboration of Edelweiss-II (Arxiv: 0912.0805, 0912.1196).

This experiment is largely similar to CDMS-II. Edelweiss-II gave only the upper limits, so in principle it became clear that most likely CDMS would not give anything in the sense of detecting (CDMS-II is somewhat more sensitive than Edelweiss-II, about 4 times at the moment). The final clarity has appeared now.

In the fresh E-print, Arxiv: 0912.3592 presents the latest (and final) results of CDMS II.

It is quite surprising that news feeds give the result as positive. In the plain, two events are registered in the potential signal area. But the fact is that the likelihood that this noise is very large - 23%.

It is possible quite seriously only by data in which the probability of a background origin of the signal below 1%. So the CDMS II data is very far from calling this a discovery or even hope for opening.

But we can talk about very good new upper limits. The new CDMS II data exclude almost the entire signal area on which Dama/Libra insists.

Sergey Popov