Measurement of CP asymmetries in D± → η‧π± and Ds± →η‧π± decays

Abstract

A search for CP violation in D± →η‧π± and Ds± →η‧π± decays is performed using proton-proton collision data, corresponding to an integrated luminosity of 3 fb-1, recorded by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. The measured CP-violating charge asymmetries are ACP (D± →η‧π±) = (- 0.61 ± 0.72 ± 0.53 ± 0.12)% and ACP (Ds± →η‧π±) = (- 0.82 ± 0.36 ± 0.22 ± 0.27)%, where the first uncertainties are statistical, the second systematic, and the third are the uncertainties on the ACP (D± →KS0 π±) and ACP (Ds± → ϕπ±) measurements used for calibration. The results represent the most precise measurements of these asymmetries to date.