Testing for new physics in singly Cabibbo suppressed D decays

TL;DR

This paper proposes sum rule tests for detecting new physics in CP violation of singly Cabibbo suppressed D decays, focusing on isospin change signatures to distinguish standard model effects from potential new physics contributions.

Contribution

It introduces novel sum rule tests based on isospin analysis to identify new physics effects in D meson CP violation measurements.

Findings

Sum rules are derived for CP asymmetries in D decays.

Violation of sum rules indicates potential new physics contributions.

The approach distinguishes standard model CP violation from new physics effects.

Abstract

We devise tests for a new physics origin of the recently measured direct CP violation in singly Cabibbo suppressed D decays. The tests take the form of sum rules for the CP asymmetries in various D decays. They are based on the fact that within the standard model CP violation arises from interference of the dominant tree amplitudes with the Delta I=1/2 penguin amplitudes. The sum rules would be violated if the observed CP violation is due to new physics contributions to the effective weak Hamiltonian that change isospin by Delta I=3/2.