Speaker
Description
A longstanding mismatch of the theoretical predictions and experimental measurements of $D$-meson mixing parameters stands at a couple orders of magnitude. The Glashow–Iliopoulos–Maiani (GIM) mechanism is responsible for the cancellations which leave $SU(3)$ breaking effects highly suppressed - to the fourth power. Higher order corrections, as well as nonperturbative effects, may give rise to stronger $SU(3)$ breaking, and account for the missing contribution. In this poster, we present our calculation of the contribution of nonlocal QCD condensates to the mass difference parameter of $D$-meson mixing. We give a comparison of two nonlocal models for the QCD condensates, as well as, for the first time, include the mixed condensate contribution. We show these contributions are larger than the box-diagram prediction, lifting the final result by an order of magnitude. Even though we unfortunately do not meet the experimental value, this research presents a clear improvement and gives a better understanding of nonperturbative QCD dynamics.
