Production of Mesotrons in the Stratosphere

Abstract

The intensity of the vertically moving ionizing penetrating cosmic-ray particles in the stratosphere is derived as a function of altitude, magnetic latitude, and energy, the purpose being to test the validity of the initial assumptions: that all the cosmic-ray mesotrons have the same mean life at rest of 2.15μsec. and are produced, nine at a time, by primary protons in the fields of air nuclei, that the cross section of an air nucleus for mesotron production by a proton is independent of the proton's energy and is equal to 2.5×${10}^{-25\mathrm{}}$ ${\mathrm{cm}}^2$, and that the kinetic energy of a primary proton is divided equally among the total energies of the mesotrons it produces. Comparison of theory and experiment shows that the multiplicity of mesotron production by protons is approximately nine for proton energies above 7×${10}^9$ ev, for a differential energy spectrum of protons, of the form $N_0{\mathcal{E}}^{-2.9\mathrm{}}$, that for proton energies below 7×${10}^9$ ev the multiplicity of mesotron production is lower than nine and the power law energy spectrum is modified, that mesotrons with mean lifetimes much less than 2.15×${10}^{-6\mathrm{}}$ sec. probably must be postulated to account for the soft component in the stratosphere, and that, as mesotrons are produced, nuclear particles are knocked forward, taking a small fraction of the available energy.