The RICH counter of the AMS experiment

The RICH counter of the AMS experiment is described and its expected performances are discussed. Prototype results are reported.Comment: 5 pages, 7 figure

Simulation of atmospheric secondary hadron and lepton flux from satellite to underground experiments

The successful simulation results obtained in the interpretation of the recent AMS measurements of proton, leptons and light nuclei particle flux, are reviewed. A similar success in being met in the analysis of secondary particle flux measured in teh atmosphere (antiprotons, muons) and in underground experiments (neutrinos)

Nuclear Cosmic Rays propagation in the Atmosphere

The transport of the nuclear cosmic ray flux in the atmosphere is studied and the atmospheric corrections to be applied to the measurements are calculated. The contribution of the calculated corrections to the accuracy of the experimental results are discussed and evaluated over the kinetic energy range 10-10$^{3}$ GeV/n. The Boron (B) and Carbon (C) elements system is used as a test case. It is shown that the required corrections become largely dominant at the highest energies investigated. The results are discussed.Comment: Proc. of 30th International Cosmic Ray Conference, Merida, Mexico; 4 page

Precise simulation of secondary particle production and propagation in the atmosphere

Precise simulation of secondary particle production and propagation in the atmosphere is a very important issue for the atmospheric neutrino oscillation studies. To this purpose a full 3-Dimensions Monte-Carlo simulation of particle transport in the atmosphere is used to compute the flux of protons, muons and neutrinos. Recent balloon borne experiments performed a set of accurate measurement of different particle flux at different altitudes in the atmosphere. This set of data can be used to test and improve the calculations for the atmospheric neutrino production. The simulation results will be reported and compared with the latest flux measurements. In the oral presentation and in the updated version of the proceedings it will be shown that the level of precision reached by these experiments could be used to constrain the nuclear models used in the simulation. The implication of these results for the atmospheric neutrino flux calculation will also be presented and discussed

Origin of the high energy proton component below the geomagnetic cutoff in near earth orbit

The high flux proton component observed by AMS below the geomagnetic cutoff can be well accounted for by assuming these particles to be secondaries originating from the interaction of Cosmic Ray protons with the atmosphere. Simulation results are reporte

Origin of light nuclei in near earth orbit

The possible sources of light nuclei populations observed recently below the geomagnetic cutoff by the AMS experiment are discussed in terms of nuclear processes: fragmentation of the incoming flux of cosmic helium on atmospheric nuclei, and nuclear coalescence from proton and helium induced reactions. Results of simulations for deuterium, tritium, helium 3 and 4, are presented.Comment: 11 pages, 4 figure

A model for A=3 antinuclei production in proton-nucleus collisions

A simple coalescence model based on the same diagrammatic approach of antimatter production in hadronic collisions as used previously for antideuterons is used here for the hadroproduction of mass 3 antinuclei. It is shown that the model is able to reproduce the existing experimental data on Tbar and 3hebar production without any additional parameter.Comment: 7 figures. submitted to Eur. Phys. J.

Experimental study of a proximity focusing Cherenkov counter prototype for the AMS experiment

A study prototype of Proximity Focussing Ring Imaging Cherenkov counter has been built and tested with several radiators using separately cosmic-ray particles and 12C beam fragmentation products at several energies. Counter prototype and experimental setup are described, and the results of measurements reported and compared with simulation results.The performances are discussed in the perspective of the final counter design.Comment: 27 pages, 16 figures, submitted to NIM

Measurement of the Omega_c Lifetime

We present the measurement of the lifetime of the Omega_c we have performed using three independent data samples from two different decay modes. Using a Sigma- beam of 340 GeV/c we have obtained clean signals for the Omega_c decaying into Xi- K- pi+ pi+ and Omega- pi+ pi- pi+, avoiding topological cuts normally used in charm analysis. The short but measurable lifetime of the Omega_c is demonstrated by a clear enhancement of the signals at short but finite decay lengths. Using a continuous maximum likelihood method we determined the lifetime to be tau(Omega_c) = 55 +13-11(stat) +18-23(syst) fs. This makes the Omega_c the shortest living weakly decaying particle observed so far. The short value of the lifetime confirms the predicted pattern of the charmed baryon lifetimes and demonstrates that the strong interaction plays a vital role in the lifetimes of charmed hadrons.Comment: 15 pages, including 7 figures; gzipped, uuencoded postscrip