Precise determination of muon and electromagnetic shower contents from a shower universality property

We consider two new aspects of extensive air shower development universality allowing to make an accurate estimation of muon and electromagnetic (EM) shower contents in two independent ways. In the first case, to get the muon (or EM) signal in water Cherenkov tanks or in scintillator detectors, it is enough to know the vertical depth of the shower maximum Xmaxv and the total signal in the ground detector. In the second case, the EM signal can be calculated from the primary particle energy and the zenith angle. In both cases, the parametrizations of muon and EM signals are almost independent on the primary particle nature, energy and zenith angle. Implications of the considered properties for mass composition and hadronic interaction studies are briefly discussed. The present study is performed on 28 000 proton, oxygen, and iron showers, generated with CORSIKA 6.735 for the E-1 spectrum in the energy range lg (E/eV)=18.5-20 and uniformly distributed in cos2θ in the zenith angle interval θ=0 deg. - 65 deg. for QGSJET II/Fluka interaction models.