The project proposes a high-statistics computation of lattice correlation functions starting from isospin-symmetric QCD and including the leading isospin-breaking effects, with the twofold aim of increasing the accuracy and evaluating the leading isospin-breaking corrections for key observables such as the energy-smeared R-ratio of e+e- into hadrons and the hadronic vacuum polarization (HVP) contributions to the muon anomalous magnetic moment, gðœ‡âˆ’ 2.
Exploiting gauge ensembles at the physical point, with spatial sizes up to L=7.5 fm and lattice spacings down to a < 0.05 fm, generated by the ETM Collaboration, we shall obtain a robust precise determination of these observables in QCD+QED with u, d, s and c quarks. By evaluating correlators of two weak currents we also plan an accurate study of inclusive hadronic tau-meson decays.
Producing first principles Standard Model (SM) predictions for the R-ratio with few hundred MeV energy resolution and for the gðœ‡âˆ’ 2 HVP window-like and possibly full contributions will play a crucial role in assessing the (dis)agreement between SM predictions and experimental data concerning both e+e- into hadrons and gðœ‡âˆ’ 2.
This is a key contribution of Lattice Field Theory to Particle Physics at the precision frontier.
Universita` degli Studi di Roma Tor Vergata (University of Rome Tor Vergata), Italy;
University of Cyprus, Cyprus;
University of Bonn, Germany;
University of Bern, Switzerland;
University of "Roma Tre", Italy;
INFN, Italy;
The Cyprus Institute, Cyprus;
Bergische Universitat Wuppertal, Germany;
DESY, Zeuthen, Germany;