Observation of the doubly Cabibbo-Suppressed decays $D^+\to K^+\pi^0\pi^0$ and $D^+\to K^+\pi^0\eta$

TL;DR

This paper reports the first observation of specific doubly Cabibbo-suppressed decays of the D+ meson, measuring their branching fractions and searching for related subprocesses using data from the BESIII detector.

Contribution

It provides the first measurements of the branching fractions for $D^+ o K^+ ho^0$ and $D^+ o K^+ ho^0 o K^+ o ext{pion}$ decays, including evidence for $D^+ o K^{*}(892)^+ o K^+ ho^0$.

Findings

First observation of $D^+ o K^+ ho^0$ and $D^+ o K^+ ho^0 o K^+ ext{pion}$ decays.

Measured branching fractions: $(2.1 imes 10^{-4})$ for $D^+ o K^+ ho^0$ and $(2.1 imes 10^{-4})$ for $D^+ o K^+ ho^0 o K^+ ext{pion}$.

Evidence for $D^+ o K^{*}(892)^+ o K^+ ho^0$ with a branching fraction of approximately $4.4 imes 10^{-4}$.

Abstract

By analyzing $e^+e^-$ annihilation data corresponding to an integrated luminosity of $2.93\,\rm fb^{-1}$ collected at the center-of-mass energy of 3.773\,GeV with the BESIII detector, we report the first observations of the doubly Cabibbo-suppressed decays $D^+\to K^+\pi^0\pi^0$ and $D^+\to K^+\pi^0\eta$. The branching fractions of $D^+\to K^+\pi^0\pi^0$ and $D^+\to K^+\pi^0\eta$ are measured to be $(2.1 \pm 0.4_{\rm stat} \pm 0.1_{\rm syst})\times 10^{-4}$ and $(2.1 \pm 0.5_{\rm stat} \pm 0.1_{\rm syst})\times 10^{-4}$ with statistical significances of 8.8$\sigma$ and 5.5$\sigma$, respectively. In addition, we search for the subprocesses $D^+\to K^{*}(892)^{+}\pi^0$ and $D^+\to K^{*}(892)^{+}\eta$ with $K^{*}(892)^+\to K^+\pi^0$. The branching fraction of $D^+\to K^{*}(892)^{+}\eta$ is determined to be $({4.4^{+1.8}_{-1.5}}_{\rm stat}\pm0.2_{\rm syst})\times10^{-4}$, with a statistical significance of 3.2$\sigma$. No significant signal for $D^+\to K^{*}(892)^{+}\pi^0$ is found and we set an upper limit on the branching fraction of this decay at the 90\% confidence level to be $5.4\times10^{-4}$.