The dependence of the emission size on the hadron mass

Abstract

The size of the emission volume of pions and kaons, r_{ππ} and r_{KK}, were measured in the hadronic Z^0 decays through the two-pion and two-kaon Bose-Einstein correlations near threshold. Recently the emitter size of the two identical baryons, ΛΛ(\bar Λ\bar Λ), was evaluated from the dependence of the fraction of the spin S=1 state on the energy near threshold where it is affected by the Pauli exclusion principle. Here we show that the r dependence on the particle masses, namely the hierarchy r_{ππ} > r_{KK} > r_{ΛΛ} observed in the Z^0 hadronic decays, is well described in terms of the Heisenberg uncertainty principle. A good description can also be obtained via the virial theorem when applied to a general QCD potential. Other available approaches are also discussed.