Measurement of CP asymmetries in D± → η′π± and D±s → η′π± decays

Abstract

A search for CPviolation in D±→η π±and D±s→η π±decays is performed using proton–proton collision data, corresponding to an integrated luminosity of 3fb−1, recorded by the LHCb experiment at centre-of-mass energies of 7and8TeV. The measured CP-violating charge asymmetries are ACP(D±→η π±) =(−0.61 ±0.72 ±0.53 ±0.12)%and ACP(D±s→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±→K0Sπ±)and ACP(D±s→φπ±)measurements used for calibration. The results represent the most precise measurements of these asymmetries to date.