Since direct searches for new particles have not yet resulted in the discovery of any kind of Beyond-the-Standard-Model (BSM) physics at high energy, indirect searches through precision measurements of low-energy observables for which equally precise theoretical predictions exist still have a crucial role to play in testing the limits of the Standard Model (SM).
These high-precision calculations have to account for contributions from quark loops, where the quarks interact non-perturbatively among themselves via the strong interaction described by Quantum Chromodynamics (QCD).
A true first-principles treatment of these observables is possible only in the fully non-perturbative framework of lattice QCD, which therefore faces the new challenge of a precision frontier: full control of both statistical and systematic uncertainties is needed.
This proposal concerns the study of the structure of the lightest pseudoscalar mesons in lattice QCD, where full control of statistical and systematic uncertainties requires runs on very fine and large lattices with physical and near-physical quark masses, resulting in very high computational demands.
Successful completion of this project would lead to a precise and truly a priori prediction of the low-energy constants (LECs) of chiral perturbation theory (PT) enabling new low-energy tests of the SM.