  We study low energy hadronic interaction models based on BESS observed cosmic
ray proton and antiproton spectra at medium high altitude. Among the three
popular low energy interaction models, we find that FLUKA reproduces results of
BESS observations on secondary proton spectrum reasonably well over the whole
observed energy range, the model UrQMD works well at relatively higher energies
whereas spectrum obtained with GHEISHA differs significantly from the measured
spectrum. Simulated antiproton spectrum with FLUKA, however, exhibits
significant deviations from the BESS observation wheras UrQMD and GHEISHA
reproduce the BESS observations within the experimental error.
