Search for the Decay $K^0_L \to \pi^0 \nu \bar{\nu}$

TL;DR

This paper reports a search for the rare decay $K^0_L o \pi^0 u ar{ u}$ at KEK, setting an upper limit on its branching ratio due to no observed candidate events.

Contribution

The study provides the first experimental upper limit on the decay's branching ratio at KEK, improving constraints on this rare process.

Findings

No candidate events observed

Upper limit on branching ratio set at $6.7 imes 10^{-8}$

Results constrain new physics models

Abstract

We performed a search for the $K^0_L \to \pi^0 \nu \bar{\nu}$ decay at the KEK 12-GeV proton synchrotron. No candidate events were observed. An upper limit on the branching ratio for the decay was set to be $6.7 \times 10^{-8}$ at the 90% confidence level.