An experiment to send neutrinos from the CERN particle physics lab in Geneva to the Gran Sasso underground in central Italy, 730 km away, was approved last week. The experiment will search for evidence of neutrino mass, which has important implications for particle physics and cosmology. Similar experiments are planned or underway in Japan and the US.
Italy is paying over half of the cost of the SwFr 71million experiment, with voluntary contributions from Belgium, France, Germany and Spain covering the rest. The experiment will start taking data in May 2005.
CERN will send around 1018 muon neutrinos to Gran Sasso every year. However, only about 2500 of these will interact with the 1000 ton target there. If the results from the SuperKamiokande atmospheric neutrino experiment in Japan are correct, then a few tens of the neutrinos will have transformed or “oscillated” into tau neutrinos. Using a laboratory rather than atmospheric source of neutrinos will mean that the initial flux of neutrinos will be known much more accurately, and will allow more precise measurements to be made.