%0 Generic
%A Stahl, Sascha
%C Heidelberg
%D 2014
%F heidok:17241
%R 10.11588/heidok.00017241
%T Measurement of CP asymmetry in muon-tagged D0->K-K+ and D0->pi-pi+ decays at LHCb
%U https://archiv.ub.uni-heidelberg.de/volltextserver/17241/
%X This thesis presents the measurement of the  time-integrated CP asymmetries in D0->K-K+ and D0->pi-pi+ decays. The analysis uses data corresponding to an integrated luminosity of 3 fb^-1 collected at the LHCb experiment in proton-proton collision at centre-of-mass energies of 7 TeV and 8 TeV. The D0 mesons are produced in semileptonic b-hadron decays, where the charge of the accompanying muon determines the initial flavour of the D0 meson. By taking the difference of the observed asymmetries in the selected D0->K-K+ and D0->pi-pi+ samples, production and detection asymmetries cancel. The difference in  CP asymmetries between the two final states is measured to be  DeltaACP = AcpKK - Acppipi = (+0.14+-0.16(stat)+-0.08(syst))%. In order to obtain a measurement of AcpKK, large samples of Cabibbo-favoured D+ meson decays are used to determine production and detection asymmetries to a high precision. The CP asymmetry is found to be AcpKK = (-0.06+-0.15(stat)+-0.10(syst))%, where the correlation coefficient between DeltaACP and AcpKK is rho=0.28. By combining these results, the CP asymmetry in  decays D0->pi-pi+ is derived to be Acppipi = (-0.20+-0.19(stat)+-0.10(syst))%. The results of this thesis show that there is no significant CP violation in D0->K-K+ and D0->pi-pi+ decays at the level of 10^-3.