Leptonic decay constants for D-mesons from 3-flavour CLS ensembles

Abstract: We report on the status of an ongoing effort by the RQCD and ALPHA Collaborations, aimed at determining leptonic decay constants of charmed mesons. Our analysis is based on large-volume ensembles generated within the CLS effort, employing N_f=2+1 non-perturbatively O(a) improved Wilson quarks, tree-level Symanzik-improved gauge action and open boundary conditions. The ensembles cover lattice spacings from a ~ 0.09 fm to a ~ 0.05 fm, with pion masses varied from 420 to 200 MeV. To extrapolate to the physical masses, we follow both the 2m_l+m_s=const. and the m_s=const. lines in parameter space.