Search for mixing-induced CP violation using partial reconstruction of B¯0→D*+Xℓ−ν¯ℓ and kaon tagging

Abstract

We describe in detail a previously published measurement of C P violation in B 0 - ¯ 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 * + ℓ − ¯ ν ℓ 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 C P violating asymmetry A C P = ( N ( B 0 B 0 ) − N ( ¯ B 0 ¯ B 0 ) ) / ( N ( B 0 B 0 ) + N ( ¯ B 0 ¯ B 0 ) ) = ( 0.06 ± 0.1 7 + 0.38 − 0.32 ) % corresponding to Δ C P = 1 − | q / p | = ( 0.29 ± 0.8 4 + 1.88 − 1.61 ) × 1 0 − 3 . This measurement is consistent and competitive with those obtained at the B factories with dilepton events.