Up Sector of Minimal Flavor Violation: Top Quark Properties and Direct D meson CP violation

TL;DR

This paper explores how minimal flavor violation in the up-quark sector affects top quark and D meson physics, highlighting potential signals of new physics such as enhanced CP violation and unique top decay modes.

Contribution

It introduces a comprehensive analysis of effective operators in up-sector minimal flavor violation, emphasizing the role of a light flavor mediator in explaining D meson CP violation and predicting novel top decay signatures.

Findings

Flavor-changing effects are generally small but can be enhanced by a light scalar mediator.

A light scalar mediator can explain observed D meson CP violation within experimental bounds.

Predicted top decay mode mimics a dijet resonance, offering a new experimental signature.

Abstract

Minimal Flavor Violation in the up-type quark sector leads to particularly interesting phenomenology due to the interplay of flavor physics in the charm sector and collider physics from flavor changing processes in the top sector. We study the most general operators that can affect top quark properties and $D$ meson decays in this scenario, concentrating on two CP violating operators for detailed studies. The consequences of these effective operators on charm and top flavor changing processes are generically small, but can be enhanced if there exists a light flavor mediator that is a Standard Model gauge singlet scalar and transforms under the flavor symmetry group. This flavor mediator can satisfy the current experimental bounds with a mass as low as tens of GeV and explain observed $D$-meson direct CP violation. Additionally, the model predicts a non-trivial branching fraction for a top quark decay that would mimic a dijet resonance.