Search for the K(L) --> PI0 PI0 E+ E- Decay in the KTeV Experiment

TL;DR

This paper reports a search for the rare decay K(L) --> PI0 PI0 E+ E- in the KTeV experiment, setting an upper limit on its branching ratio after observing one candidate event.

Contribution

First search for the K(L) --> PI0 PI0 E+ E- decay mode in the KTeV experiment, providing an upper limit on its branching ratio.

Findings

Observed one candidate event with expected background of 0.3.

Set an upper limit for the branching ratio at 6.6 x 10^-9.

Results constrain theoretical models of CP violation.

Abstract

The recent discovery of a large CP violating asymmetry in K(L) --> PI+ PI- E+ E- mode has prompted us to seach for the associated K(L) --> PI0 PI0 E+ E- decay mode in the KTeV-E799 experiment at Fermilab. In 2.7E+11 K(L) decays, one candidate event has been observed with an expected background of 0.3 event, resulting in an upper limit for the K(L) --> PI0 PI0 E+ E- branching ratio of 6.6E-09 at the 90% confidence level.