Search for mixing-induced CP violation using partial reconstruction of B ¯ 0 →d∗+X- ν ¯ and kaon tagging SEARCH for MIXING-INDUCED CP VIOLATION ⋯ J. P. LEES et al.

Abstract

We describe in detail a previously published measurement of CP violation in B0-B¯0 oscillations, based on an integrated luminosity of 425.7 fb-1 collected by the BABAR experiment at the PEPII collider. We apply a novel technique to a sample of about 6 million B¯0→D∗+-ν¯ decays selected with partial reconstruction of the D∗+ meson. The charged lepton identifies the flavor of one B meson at its decay time, the flavor of the other B is determined by kaon tagging. We determine a CP violating asymmetry ACP=(N(B0B0)-N(B¯0B¯0))/(N(B0B0)+N(B¯0B¯0))=(0.06±0.17-0.32+0.38)% corresponding to ΔCP=1-|q/p|=(0.29±0.84-1.61+1.88)×10-3. This measurement is consistent and competitive with those obtained at the B factories with dilepton events.