This paper presents a first study of the decay constants of the charged, or flavor-off-diagonal, pseudoscalar mesons to two loops for three flavors of sea quarks, in partially quenched chiral perturbation theory ($\mathrm{PQ}\chi \mathrm{PT}$). Explicit analytical expressions up to $\mathcal{O}(p^6)$ in the momentum expansion are given. The calculations have been performed within the supersymmetric formulation of $\mathrm{PQ}\chi \mathrm{PT}$. We also present some numerical results to indicate the size of the corrections.

• Received 18 January 2005

DOI:https://doi.org/10.1103/PhysRevD.71.094502