Experts want to test claims that the stuff has been discovered

Nov 4, 2009 07:47 GMT  ·  By

An Italian team argued some time ago that it had discovered dark matter, in a statement that shocked the world of astrophysics. However, when other research groups wanted to replicate the experiments, they had a very difficult time doing so. It may be that they will have to reach the same conclusion as the Italians, only without using any of their equipment or expertise. The main component in the previous study was ultrapure sodium iodide crystals, which are extremely difficult to procure.

The first claims that direct evidence of dark matter had been detected came from near L'Aquila, Italy, and was made by researchers working with the Gran Sasso National Laboratory's (GSNL) DAMA experiment, a dark matter detector. The massive instrument featured no less than 250 kilograms of USIC, which were buried some 1,400 meters (4,600 feet) underground, directly beneath the Gran Sasso mountain. For over ten years, the Italian group collected data of the changes that took place in the detector, and drew conclusions based on these observations.

They said that the periodical flashes of light they had noticed being emitted by nuclei in the USIC might have been generated by interactions between the crystals and dark matter. Additionally, the team reveals, the number of flashes varied significantly depending on the season, which is also in tune with current thinking on dark matter. It is believed that the amount of the stuff with which the Earth comes into contact depends considerably on the planet's position within the galaxy, Nature News reports.

“It could be right, they're careful people. I think it deserves to be checked,” Princeton University professor Frank Calaprice said of the DAMA team. There are researchers who say that the entire set of Italian experiments was flawed, and that the flashes of light came from radioactive contamination of the crystals. The thing is that physicists may never find out, because they cannot replicate the experiments in their entirety. For one, the Italian team refuses to provide help to other science groups, and it also holds an intellectual-property agreement with the company that supplied it with the USIC.

A detector similar to DAMA exists at the GSNL and it could be converted from detecting neutrinos to detecting interactions between normal matter and its dark cousin. However, The Borexino collaboration cannot go on because the group that first allegedly detected dark matter says there are too many scientific barriers in converting the experiment. “Borexino cannot ensure the fulfilment of all the stringent requirements necessary for a reliable measurement in this field,” said National Institute of Nuclear Physic physicist Rita Bernabei, who is also the principal investigator at DAMA.