Measurement of sin2phi_1 at Belle

摘要

With 6.2 fb^-1 of data collected on the Upsilon(4S), Belle reports its firstmeasurement of sin 2\phi_1 = 0.45^{+0.43}_{-0.44}(stat)^{+0.07}_{-0.09}(sys).The result was obtained by fitting the proper time distribution of flavortagged and fully reconstructed neutral B mesons decays to five differentcharmonia plus a Kshort or Klong channels. In this paper the analysis andresults will be described briefly.