An Update on the Isospin-Breaking Effects in the Pion Decay Constant with Staggered Quarks

Abstract

We present an update on the ongoing computation of the isospin-breaking effects in the Pion Decay Constant from the BMW Collaboration. The calculation is carried out with N${}_f$=2+1+1 staggered quarks with a near-physical pion mass and QED${}_{\text{L}}$. We give an update on the isosymmetric value and the current determination used to compute the gradient-flow scale $w_0$, then we present some preliminary results of the valence-valence contribution to the axial-pseudoscalar correlator for different volumes and lattice spacings. We also discuss the next steps and plans.

10 pages, 6 figures, Contribution to the 42nd International Symposium on Lattice Field Theory, 2nd-8th November 2025, TIFR, Mumbai, India