Current status of the T2K experiment

The T2K long-baseline neutrino-oscillation experiment was started in January 2010 for the purpose of physics data-taking. Until the massive earthquake on March 11, 2011 in Japan, 1.43x1020 pot data were accumulated. In this data, 6 possible νe appearance candidates are found for expected background of 1.5±0.3(syst.) if sin2 2θ13 = 0 is assumed. The probability that 6 or more events can be observed for 1.5±0.3 expected events is 7x10-3, equivalent to 2.5σ significance. This is the first indication of a νe appearance or, in other words, the first indication of a non-zero sin2 2θ13.