Speaker
Erik Lundstrum
(Columbia University)
Description
The precision of current lattice QCD calculations of the direct CP-violating parameter $\varepsilon’$ now requires the inclusion of $\Delta I = \frac{1}{2}$ rule-enhanced, isospin-breaking effects. Here we give an update on the program to include electromagnetism and quark mass differences in a first-principles calculation of $\varepsilon’$. We combine finite-volume hadronic matrix elements with an infinite-volume photon propagator. In order to avoid large finite-volume effects due to low-energy $\pi\pi\gamma$ states, we omit low-energy photons but show this introduces a negligible error. Finally, we discuss technical details related to the mixing of the I = 0 and I = 2 decay channels and the GEVP.
| Parallel Session (for talks only) | Quark and lepton flavor physics |
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Authors
Erik Lundstrum
(Columbia University)
Prof.
Norman Christ
(Columbia University)
