---
abstract: 'The $\rm DO \! \! \! \!/ \, $ collaboration has measured a deviation from the standard model (SM) prediction in the like sign dimuon asymmetry in semileptonic $b$ decay with a significance of $3.2 \, \sigma$. We discuss how minimal flavour violating (MFV) models with multiple scalar representations can lead to this deviation through tree level exchanges of new MFV scalars. We review how the two scalar doublet model can accommodate this result and discuss some of its phenomenology. Limits on electric dipole moments suggest that in this model the coupling of the charged scalar to the right handed $u$-type quarks is suppressed while its coupling to the $d$-type right handed quarks must be enhanced. We construct an extension of the MFV two scalar doublet model where this occurs naturally.'
author:
- |
    Michael Trott${}^1$ and Mark B. Wise${}^2$\
    ${}^1$ Perimeter Institute for Theoretical Physics, Waterloo ON, N2L 2Y5, Canada.\
    ${}^2$ California Institute of Technology, Pasadena, CA, 91125, USA,
title: 'On theories of enhanced CP violation in $B_{s,d}$ meson mixing.'
---

=by 60 =99=99 by -60 by 99

Introduction
============

The $\rm DO \! \! \! \!/$ collaboration has reported a $3.2 \, \sigma$ deviation from the 