DAMA/LIBRA claims to see Dark matter

Today, at the conference NO-VE (IV International Workshop on neutrino oscillations) in Venice, collaboration DAMA/LIBRA claimed to see Dark Matter (DM) interactions in their detector. The effect is at the 8.2 sigma level (which means that the chance that it is a background that mimics their signal is WAY smaller than 1%). See their talk here. Here is their website.

Their search technique is based on DM interacting with their detector material (which happens to be well-known NaI), so they can trigger on detector’s “matter recoil” when DM particle hits the detector. In principle, it is a hard way to search for DM, as many non-DM backgrounds can also interact with NaI! For example, neutrons… Well, the deal with DAMA is that they look for the modulations in their signal that can appear due to Earth’s motion around the Sun (see Drukier, Freese and Spergel’s paper in Phys Rev D48). So one looks for a cosine-type signal over some years of data collecting. This cosine-type signal is very difficult to emulate by any (known) background. Nevertheless, (known) background studies are very important — and about half of the above talk is about them

This result is interesting, but still controversial… See, that XENON experiment has something to say about it — they used liquid xenon as their detecting media, which is very similar in properties to iodine in NaI that DAMA used. The thing is, they didn’t see anything…