Search for D^0-\bar{D^0} mixing using semileptonic decays at Belle

TL;DR

This study searched for D^0-ar{D^0} mixing using semileptonic decays at Belle, setting an upper limit on the mixing rate with 140 fb^-1 of data, contributing to understanding charm meson behavior.

Contribution

First search for D^0-ar{D^0} mixing using semileptonic decays at Belle, providing an upper limit on the mixing rate.

Findings

Upper limit for mixing rate r_D < 1.4 x 10^-3 at 90% C.L.

Used 140 fb^-1 of Belle data for analysis.

Tagged D^0 flavor via slow pion charge.

Abstract

A search for mixing in the neutral D meson system was performed using semileptonic D^0 -> K- e+ nu decays. The flavor of neutral D mesons at production was tagged by the charge of the slow pion from the decay D*+ -> D^0 \pi+. The measurement was performed using 140 fb^-1 of data recorded by the Belle detector. The yield of right and wrong sign decays arising from un-mixed and mixed events, respectively, was determined by a fit to kinematic observables. From the number of signal events we derive an upper limit for the time-integrated mixing rate r_D < 1.4 x 10^-3 at 90% C.L.