Search for the decay $D^{0} \to \pi^{0} \nu \bar{\nu}$

TL;DR

This paper reports the first experimental search for the rare decay $D^{0} o c0 5 5$, setting an upper limit on its branching fraction and providing the first constraint on such charmed-hadron dineutrino decays.

Contribution

It introduces the first experimental search for the decay $D^{0} o c0 5 5$ and establishes an upper limit on its branching fraction.

Findings

No significant signal observed.

Upper limit on branching fraction set at $2.1 imes 10^{-4}$.

First experimental constraint on charmed-hadron dineutrino decays.

Abstract

We present the first experimental search for the rare charm decay $D^{0} \to \pi^{0} \nu \bar{\nu}$. It is based on an $e^+e^-$ collision sample consisting of $10.6\times10^{6}$ pairs of $D^0\bar{D}^0$ mesons collected by the BESIII detector at $\sqrt{s}$=3.773 GeV, corresponding to an integrated luminosity of 2.93~fb$^{-1}$. A data-driven method is used to ensure the reliability of the background modeling. No significant $D^{0} \to \pi^{0} \nu \bar{\nu}$ signal is observed in data and an upper limit of the branching fraction is set to be $2.1\times 10^{-4}$ at the 90$\%$ confidence level. This is the first experimental constraint on charmed-hadron decays into dineutrino final states.