Precise measurement of the vertical muon spectrum in the range 20-500 GeV/c

Abstract. The 300 ton cosmic ray spectrograph (MARS) has been used to measure the vertical momentum spectrum of cosmic ray muons in the momentum range 20-500GeVlc at sea level. The differential spectrum is well represented by the logarithmic polyi:omial p3 N ~= =)-0.524-iO.366 (Inp)--0.0445 (lnp)z+OGOOS (InpI3 where p is in Gev/c and N(p) is in s-l cm- * sr- (GeV/c)-. 1.