If you don’t know this, Xenon 100 released their most recent limits on dark matter. This was covered in the New York Times, and also by Sean. The data can be found in this paper in the arxiv: “Dark Matter Results from 100 Live Days of XENON100 Data“.
The main key of these experiments is to keep some region where data is supposed to be located at completely hidden from the experimentalists until they have decided how to account for all the systematics with the control region. Once they do this, they unblind the data and hope that enough events are in the discovery region to have a discovery. These regions also can have some events that are due to other sources which the experimenters have tried as hard as possible to remove. The data was unblinded about a week ago, and everything was essentially ready for writing a paper. This last step is very fast, because there are very few events expected anyhow.
Previous to the end announcement: that no dark mater was found yet in the Xenon direct experiment, I had been hearing rumors all week long that Xenon 100 had actually seen something.
Well, you can call this the sociology of the field: some people might have been expecting something and claimed that it was in the data. Otherwise its a publicity stunt. There are two experiments with claims of detection: DAMA/LIBRA and COGENT. Many people are very suspicious of the first, and a lot of them should be also worried about the second. With the new data it seems as if both positives are ruled out unless one has a very contrived model of dark matter.
Dark matter is like Count Dracula. It will take more than a few nails in the coffin to put this neo-aether idea to rest. Fortunately, there are now three studies linking the temperature of a test mass to its gravitational weight. These studies suggest the possibility that luminosity is the source of gravitational attraction. Astronomers all know that luminosity emanates from all gravitationally bound bodies in the universe such as binary stars, planetary systems, galaxies and clusters. My studies show a 1.9%, 8.9%, 9.6% and a 16% increase in the weight of the test mass when these test masses were placed between a 1000 W hot source and a cold source. Such unexpected anomalous results challenge the principle of equivalence upon which General Relativity depends and Einstein’s interpretation of E = mc^2. But go a ahead and ignore them. Maybe someday they will find that dark matter (and dark energy).
http://vixra.org/abs/0907.0018
http://arxiv.org/abs/0803.1730