Charm meson oscillations are observed in a time-dependent analysis of the ratio of D^0→K^+π^-π^+π^- to D^0→K^-π^+π^-π^+ decay rates, using data corresponding to an integrated luminosity of 3.0 fb^-1 recorded by the LHCb experiment. The measurements presented are sensitive to the phase-space averaged ratio of doubly Cabibbo-suppressed to Cabibbo-favored amplitudes r_D^K3π and the product of the coherence factor R_D^K3π and a charm mixing parameter y_K3π^'. The constraints measured are r_D^K3π=(5.67±0.12)×10^-2, which is the most precise determination to date, and R_D^K3πy_K3π^'=(0.3±1.8)×10^-3, which provides useful input for determinations of the CP-violating phase γ in B^±→DK^±, D→K^∓π^±π^∓π^± decays. The analysis also gives the most precise measurement of the D^0→K^+π^-π^+π^- branching fraction, and the first observation of D^0-D[over ¯]^0 oscillations in this decay mode, with a significance of 8.2 standard deviations.
First Observation of D^0-D[over ¯]^0 Oscillations in D^0→K^+π^-π^+π^- Decays and Measurement of the Associated Coherence Parameters
VELTRI, MICHELE;
2016
Abstract
Charm meson oscillations are observed in a time-dependent analysis of the ratio of D^0→K^+π^-π^+π^- to D^0→K^-π^+π^-π^+ decay rates, using data corresponding to an integrated luminosity of 3.0 fb^-1 recorded by the LHCb experiment. The measurements presented are sensitive to the phase-space averaged ratio of doubly Cabibbo-suppressed to Cabibbo-favored amplitudes r_D^K3π and the product of the coherence factor R_D^K3π and a charm mixing parameter y_K3π^'. The constraints measured are r_D^K3π=(5.67±0.12)×10^-2, which is the most precise determination to date, and R_D^K3πy_K3π^'=(0.3±1.8)×10^-3, which provides useful input for determinations of the CP-violating phase γ in B^±→DK^±, D→K^∓π^±π^∓π^± decays. The analysis also gives the most precise measurement of the D^0→K^+π^-π^+π^- branching fraction, and the first observation of D^0-D[over ¯]^0 oscillations in this decay mode, with a significance of 8.2 standard deviations.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
