On the Dalitz plot analysis of the B --> K eta gamma decays

TL;DR

This paper analyzes the Dalitz plot of B --> K eta gamma decays, identifying mechanisms for decay amplitudes with soft mesons using heavy meson chiral perturbation theory, and compares theoretical rates with experimental data.

Contribution

It introduces a theoretical framework for understanding decay amplitudes in specific Dalitz plot regions of B --> K eta gamma decays using heavy meson chiral perturbation theory.

Findings

Partially integrated decay rates agree with experimental results.

Nonresonant decay modes dominate when K or eta are soft.

Analysis extends to B --> K eta' gamma Dalitz plot.

Abstract

Recently B-factories have published new results on the $B \to K \eta \gamma$ decays being inspired by the theoretical suggestion to search for new physics in $B \to P_1 P_2 \gamma$ decays. Using heavy meson chiral perturbation theory we find mechanism which governs the amplitude in parts of the Dalitz plot where either $K$ or $\eta$ mesons are soft. The dominant contributions in these cases are coming from the nonresonant decay modes. We discuss also $B \to K \eta' \gamma$ Dalitz plot. Our partially integrated rates are in agreement with the experimental findings.