New Physics effects in D^+ \rightarrow K^- \pi^+ \pi^+

TL;DR

This paper investigates potential new physics contributions to CP asymmetry in D+ to K- pi+ pi+ decays, showing that beyond Standard Model models can significantly enhance CP violation predictions.

Contribution

The study introduces several beyond Standard Model scenarios, including toy models, Left-Right models, and charged Higgs models, to explain possible large CP asymmetries.

Findings

Standard Model predicts negligible CP asymmetry.

Toy model can increase CP asymmetry to about 30%.

Left-Right models can reach up to 25% CP asymmetry.

Abstract

In this paper, we study the Cabibbo favored three body non-leptonic D^+ \rightarrow K^- \pi^+ \pi^+ decay. We show that the corresponding direct CP asymmetry is so tiny in the framework of the Standard Model and is out of the experimental range. Motivated by this result we extend the study of the CP asymmetry to include a toy model with CP violating weak phase equals 20 degrees in a_2, a model with extra gauge bosons within Left-Right Grand Unification models and a model with charged Higgs boson. We show that the toy model can strongly improve the SM prediction of the CP asymmetry to be about 30%. The largest CP asymmetry can be achieved in the non-manifest Left-Right models where a CP asymmetry up to 25% can be reached. For the two Higgs doublets models the CP asymmetry is of order 10^{-3}.