Semileptonic decay

In particle physics the semileptonic decay of a hadron is a decay causing by the weak force in which one lepton (and the corresponding neutrino) is produced in addition to one or more hadrons. An example for this can be

This is to be contrasted with purely hadronic decays, such as
K0
 → 
π+
 + 
π−
, which are also mediated by the weak force.

Semileptonic decays of neutral kaons have been used to study kaon oscillations.