Comment on "A possible explanation of the D0 like-sign dimuon charge aymmetry"

TL;DR

This paper critically examines a proposed second order amplitude contribution to CP asymmetry in B decays, demonstrating that it actually cancels out and does not contribute as previously claimed.

Contribution

It provides a detailed analysis showing that the second order amplitude contribution to CP asymmetry in B decays vanishes, challenging prior claims.

Findings

The second order amplitude with intermediate ar u d in a loop vanishes.

The claimed dominant contribution to CP asymmetry does not exist.

The analysis refutes previous assumptions about the amplitude's impact.

Abstract

We show that a contribution due to a second order amplitude with intermediate $\bar u d$ in a loop, which was claimed by Descotes-Genon and Kamenik to dominate the CP asymmetry in $b \to c \ell \nu$, vanishes.