Radiative three-body D-meson decays in and beyond the standard model

Nico Adolph; Joachim Brod; Gudrun Hiller

doi:10.1140/epjc/s10052-021-08832-3

2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2021) 81: 45
https://doi.org/10.1140/epjc/s10052-021-08832-3

Regular Article – Theoretical Physics

Radiative three-body D-meson decays in and beyond the standard model

Nico Adolph¹^,2, Joachim Brod² and Gudrun Hiller¹^c

¹ Fakultät Physik, TU Dortmund, Otto-Hahn-Str. 4, 44221, Dortmund, Germany
² Department of Physics, University of Cincinnati, 45221, Cincinnati, OH, USA

^c ghiller@physik.uni-dortmund.de

Received: 6 October 2020
Accepted: 1 January 2021
Published online: 18 January 2021

Abstract

We study radiative charm decays $D \to P_{1} P_{2} γ$ $D \rightarrow P_1 P_2 \gamma$ , $P_{1, 2} = π, K$ $P_{1,2}=\pi ,K$ in QCD factorization at leading order and within heavy hadron chiral perturbation theory. Branching ratios including resonance contributions are around $\sim 10^{- 3}$ $\sim 10^{-3}$ for the Cabibbo-favored modes into $K π γ$ $K \pi \gamma$ and $\sim 10^{- 5}$ $\sim 10^{-5}$ for the singly Cabibbo-suppressed modes into $π^{+} π^{-} γ, K^{+} K^{-} γ$ $\pi ^+ \pi ^- \gamma , K^+ K^- \gamma$ , and thus in reach of the flavor factories BES III and Belle II. Dalitz plots and forward–backward asymmetries reveal significant differences between the two QCD frameworks; such observables are therefore ideally suited for a data-driven identification of relevant decay mechanisms in the standard-model dominated $D \to K π γ$ $D \rightarrow K \pi \gamma$ decays. This increases the potential to probe new physics with the $D \to π^{+} π^{-} γ$ $D \rightarrow \pi ^+ \pi ^- \gamma$ and $D \to K^{+} K^{-} γ$ $D \rightarrow K^+ K^- \gamma$ decays, which are sensitive to enhanced dipole operators. CP asymmetries are useful to test the SM and look for new physics in neutral $| Δ C | = 1$ $|\Delta C|=1$ transitions. Cuts in the Dalitz plot enhance the sensitivity to new physics due to the presence of both s- and t, u-channel intermediate resonances.

© The Author(s) 2021

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