Measurement of the CKM Angle γ Using B0 → DK*0 with D → K0S π+ π− Decays

A model-dependent amplitude analysis of the decay B0 → D (K0S π+ π−) K∗0 is performed using proton-proton collision data corresponding to an integrated luminosity of 3.0 fb^−1, recorded at √s=7 and 8 TeV by the LHCb experiment. The CP violation observables x± and y±, sensitive to the CKM angle γ, are measured to be x− = −0.15 ± 0.14 ± 0.03 ± 0.01, y− = 0.25 ± 0.15 ± 0.06 ± 0.01, x+ = 0.05 ± 0.24 ± 0.04 ± 0.01, y+ = −0.65{−0.23}{+0.24} ± 0.08 ± 0.01, where the first uncertainties are statistical, the second systematic and the third arise from the uncertainty on the D → K0S π+ π− amplitude model. These are the most precise measurements of these observables. They correspond to γ = (80{−22}{+21})° and r_B0 = 0.39 ± 0.13, where r_B0 is the magnitude of the ratio of the suppressed and favoured B0 → D K+ π− decay amplitudes, in a K π mass region of ±50 MeV around the K*(892)0 mass and for an absolute value of the cosine of the K*0 decay angle larger than 0.4.