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Recently the AMS-02 collaboration has published the measurement of the cosmic antiproton to proton ratio ¯ p/p and the ¯ p flux with a high precision up to ∼ 450 GeV. In this work, we perform a systematic analysis of the secondary antiproton flux generated by the cosmic ray interaction with the interstellar gas. The uncertainty of the prediction originates from the cosmic ray propagation process and the hadronic interaction models. Although the cosmic ray propagation parameters have been well controlled by the AMS-02 B/C ratio data for a specified model, different propagation models can not be discriminated by the B/C data. The ¯ p flux is also calculated for several hadronic interaction models, which are generally adopted by the cosmic ray community. However, the results for different hadronic models do not converge. We find the EPOS LHC model, which seems to fit the collider data very well, predicts a slightly lower ¯ p/p ratio than the AMS-02 data at the high energy end. Finally we derive the constraints on the dark matter annihilation cross section from the AMS-02 ¯ p/p ratio for different propagation and hadronic interaction models. PACS numbers: 96.50.S-,95.35.+d

We report new measurements of the muon spectra and the muon charge ratio at ground level in the momentum range from 200 MeV͞c to 120 GeV͞c for two different geomagnetic locations. Above 0.9 GeV͞c the absolute spectra measured in the two locations are in good agreement and are about 10% to 15% lower than previous experimental results. At lower momenta the data show latitude dependent geomagnetic effects. These observations are important for the understanding of the observed neutrino anomaly. PACS numbers: 96.40.Tv, 96.40.Kk, 14.60.PqPrecise measurements of the muon energy spectrum and charge ratio at sea level over a wide energy range provide information on the propagation of cosmic rays in the atmosphere. Together with data on the primary cosmic rays, muon measurements can be used as a test to check calculations of atmospheric cascades and neutrino fluxes [1]. These latter calculations are used to interpret the recent re-

We report on the hydrogen nuclei (protons and deuterons) spectrum from 0.15 to 200 GeV and on the helium nuclei spectrum over the energy range from 0.2 to 100 GeV nucleon~1 at the top of the atmosphere measured by the balloon-borne experiment Cosmic Antiparticle Ring-Imaging Cerenkov Experiment (CAPRICE), which was Ñown from Lynn Lake, Manitoba, Canada, on 1994 August 8È9. We also report on the proton spectrum over the energy range from 0.15 to 4.2 GeV. The experiment used the NMSU-WiZard/CAPRICE balloon-borne magnet spectrometer equipped with a solid radiator RingImaging Cerenkov (RICH) detector and a silicon-tungsten calorimeter for particle identiÐcation. This was the Ðrst time a RICH was used together with an imaging calorimeter in a balloon-borne experiment. These detectors allowed for clear particle identiÐcation, as well as excellent control of the detector efficiencies. The data were collected during 18 hr at a residual mean atmospheric depth of 3.9 g cm~2. With this apparatus 516,463 hydrogen and 32,457 helium nuclei were identiÐed in the rigidity range 0.4 to 200 GV and 1.2 to 200 GV, respectively. The observed energy spectrum at the top of the atmosphere can be represented by (1.1^0

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