Heavy-quark physics with a tmQCD valence action

Authors: A. Bussone, S. Chaves, G. Herdoiza, C. Pena, D. Preti, J.A. Romero, J. Ugarrio

We introduce a mixed-action approach based on CLS ensembles, where a valence Nf =2+1+1 Twisted Mass QCD action is combined with the Nf =2+1 non-perturbatively O(a)-improved Wilson sea sector. We show that for maximally twisted valence quarks, the automatic O(a)- improvement of this set-up holds up to lattice artifacts coming from sea quark mass effects. Furthermore, we introduce a three-dimensional Gradient Flow smearing in order to tame the signal to noise ratio problem.