Search for Mixing and CP Violation in Charm Decays

TL;DR

This paper reports on a comprehensive search for mixing and CP violation in charm decays using Fermilab's large dataset, setting new limits on these phenomena within the Standard Model and beyond.

Contribution

It provides the most extensive analysis to date of charm mixing and CP violation, establishing new experimental limits and exploring potential signs of new physics.

Findings

Set upper limits on charm mixing parameter r_mix

Established preliminary limits on CP asymmetry A_CP

Found no significant evidence of mixing or CP violation

Abstract

Standard model mixing and CP violation are expected to be small in the charm sector. Some argue that only in the presence of new physics do we currently expect to observe these effects. Fermilab experiment E791 has the largest sample of reconstructed charm decays recorded to date. We have made an exhaustive search for D0 D0-bar mixing and CP violation in this data. We present the charm mixing limits on the mixing parameter r_mix using hadronic and semileptonic decays, and also present preliminary limits on the CP asymmetry parameter, A_CP, for Cabibbo suppressed decays.