Measurement of the CKM angle φ 1 in B 0 → ¯ D ( * ) 0 h 0 , ¯ D 0 → K 0 S π + π − decays with time-dependent binned Dalitz plot analysis

Abstract

We report a measurement of the C P -violation parameter φ 1 obtained in a time-dependent analysis of B 0 → ¯ D ( * ) 0 h 0 decays followed by ¯ D 0 → K 0 S π + π − decay. A model-independent measurement is performed using the binned Dalitz plot technique. The measured value is φ 1 = 11.7 ° ± 7.8 ° ( stat ) ± 2.1 ° ( syst ) . Treating sin 2 φ 1 and cos 2 φ 1 as independent parameters, we obtain sin 2 φ 1 = 0.43 ± 0.27 ( stat ) ± 0.08 ( syst ) and cos 2 φ 1 = 1.06 ± 0.33 ( stat ) + 0.21 − 0.15 ( syst ) . The results are obtained with a full data sample of 772 × 1 0 6 B ¯ B pairs collected near the Υ ( 4 S ) resonance with the Belle detector at the KEKB asymmetric-energy e + e − collider.