Measurement of the flux of atmospheric muons with the CAPRICE94 apparatus - art. no. 032007

A new measurement of the momentum spectra of both positive and negative muo ns as a function of atmospheric depth was made by the balloon-borne experim ent CAPRICE93. The data were collected during ground runs in Lynn Lake on 1 9 and 20 July 1994 and during the balloon flight on 8 and 9 August 1994. We present results that cover the momentum intervals 0.3-40 GeV/c for mu(-) a nd 0.3-2 GeV/c for mu(+), for atmospheric depths from 3.3 to 1000 g/cm(2), respectively. Good agreement is found with previous measurements for high m omenta, while at momenta below 1 GeV/c we find latitude dependent geomagnet ic effects. These measurements are important cross-checks for the simulatio ns carried out to calculate the atmospheric neutrino fluxes and to understa nd the observed atmospheric neutrino anomaly.