Hadronic Physics and Scale Setting from Lattice QCD with Wilson-type fermions

We present a lattice QCD setup aimed at high-precision calculations of light- and charm-quark physics. We employ a mixed action approach, in which two different regularizations of the fermionic action are used for the sea and valence sectors. More specifically, the sea sector is based on $N_f=2+1$ non-perturbatively O(a)-improved Wilson fermions, while up/down, strange and charm quarks are considered in the valence sector using Wilson twisted mass quarks at maximal twist. By also considering the case where O(a)-improved Wilson fermions are used in the sea and valence sectors, we have carried out a universality test in the up/down and strange quarks sector. This provides strong evidence of proper control of the approach to the continuum limit in these lattice QCD formulations. We will describe a scale setting procedure and its impact on charm-quark observables. The use of a mixed action requires a matching of the quark masses of the sea and valence sectors to preserve the unitarity of the continuum theory. The external input used in the scale setting procedure corresponds to the use of the pion and kaon masses and decay constants in the isospin symmetric limit of QCD. The gradient flow scale t_0 is used as an intermediate scale, whose physical value can be determined as a result of the scale setting. We employ model variation techniques to evaluate all relevant systematic uncertainties. Finally, the results of the scale setting are applied to charm-quark sector in which accurate determinations of the charm quark mass and of the decay constants of the D and Ds mesons are obtained.

Supervisor: Gregorio Herdoíza

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