Implications of the LHCb Evidence for Charm CP Violation

TL;DR

This paper discusses the implications of LHCb's evidence for CP violation in D meson decays, analyzing its compatibility with the Standard Model and potential extensions, while highlighting theoretical challenges in precise calculations.

Contribution

It provides a qualitative analysis of non-Standard Model operators needed to explain the observed CP violation and explores constraints from other processes within an effective theory framework.

Findings

Evidence suggests possible CP violation beyond the Standard Model

Certain non-SM operators can account for the observed effects

Constraints from other processes limit the parameter space of new operators

Abstract

The LHCb collaboration recently announced preliminary evidence for CP violation in D meson decays. We discuss this result in the context of the standard model (SM), as well as its extensions. In the absence of reliable methods to evaluate the hadronic matrix elements involved, we can only estimate qualitatively the magnitude of the non-SM tree level operators required to generate the observed central value. In the context of an effective theory, we list the operators that can give rise to the measured CP violation and investigate constraints on them from other processes.