Theory of Cosmic-Ray Mesons

The quantum theory of damping developed by two of us (Heitler and Peng) is applied to the production of mesons by proton-proton collisions. For this purpose the modification of the meson theory proposed by Møller and Rosenfeld is used. A primary radiation consisting of protons with a suitable energy spectrum is assumed, and it is shown that the rate of meson production is so high that nearly all mesons are produced in a top layer of the atmosphere of thickness 15-30 cm ${\mathrm{H}}_2$O. The variation of the meson intensity with energy, height, and geomagnetic latitude is found to be in good agreement with the experiments. The transverse mesons, which have a very short lifetime, are seen to give, by decay, a satisfactory account of the soft component in the high atmosphere. A number of other effects (meson showers, transformation into neutretto's) are discussed in Sections VI and VII.