Nov. 27, 2009 Physicists from the Japanese-led multi-national
T2K neutrino collaboration have just announced that over the
weekend they detected the first neutrino events generated by
their newly built neutrino beam at the J-PARC (Japan Proton
Accelerator Research Complex) accelerator laboratory in Tokai,
Japan. Protons from the 30-GeV Main Ring synchrotron were
directed onto a carbon target, where their collisions produced
charged particles called pions. These pions travelled through a
helium-filled volume where they decayed to produce a beam of the
elusive particles called neutrinos. These neutrinos then flew
200 metres through the earth to a sophisticated detector system
capable of making detailed measurements of their energy,
direction, and type. The data from the complex detector system
is still being analysed, but the physicists have seen at least 3
neutrino events, in line with the expectation based on the
current beam and detector performance. This detection therefore
marks the beginning of the operat