Cosmic Ray Energetics And Mass for the International Space Station (ISS-CREAM)

International audienc

A simulation study of Top and Bottom Counting Detectors in ISS-CREAM experiment for cosmic ray electron physics

International audienceThe Cosmic Ray Energetics and Mass experiment at the International Space Station (ISS-CREAM) is developed for studying the origin, acceleration and propagation mechanism of high energy cosmic rays. The Top and Bottom Counting Detectors (TCD/BCD), sub-detectors of the ISS-CREAM instrument, are developed for electron/ γ -ray physics. The TCD/BCD help distinguish electrons from protons by comparing the hit and shower width distributions for electrons and protons. The e/p separation capability of the TCD/BCD is studied by using the GEANT3 simulation package, and optimal parameters for the e/p separation are obtained

Measurement of Muon antineutrino quasielastic scattering on a hydrocarbon target at Eν∼3.5 GeV

We have isolated ν̄μ charged-current quasielastic (QE) interactions occurring in the segmented scintillator tracking region of the MINERvA detector running in the NuMI neutrino beam at Fermilab. We measure the flux-averaged differential cross section, dσ/dQ2, and compare to several theoretical models of QE scattering. Good agreement is obtained with a model where the nucleon axial mass, MA, is set to 0.99 GeV/c2 but the nucleon vector form factors are modified to account for the observed enhancement, relative to the free nucleon case, of the cross section for the exchange of transversely polarized photons in electron-nucleus scattering. Our data at higher Q2 favor this interpretation over an alternative in which the axial mass is increased. © 2013 American Physical Society

Measurement of muon neutrino quasielastic scattering on a hydrocarbon target at Eν∼3.5 GeV

We report a study of νμ charged-current quasielastic events in the segmented scintillator inner tracker of the MINERvA experiment running in the NuMI neutrino beam at Fermilab. The events were selected by requiring a μ- and low calorimetric recoil energy separated from the interaction vertex. We measure the flux-averaged differential cross section, dσ/dQ2, and study the low energy particle content of the final state. Deviations are found between the measured dσ/dQ2 and the expectations of a model of independent nucleons in a relativistic Fermi gas. We also observe an excess of energy near the vertex consistent with multiple protons in the final state. © 2013 American Physical Society