Contributions to the Τ-meson investigation

Summary  Two Τ-mesons have been observed in photographic emulsions exposed to cosmic rays at an altitude of 26 000 metres. The corresponding data are summarized in par.2. The process of decay of Τ-mesons is considered in par.3 where, by means of a statistical consideration applied to the measurements on Τ-mesons observed by various authors, it is proved that the process of decay in 3 Τ is by far the more likely. The spectrum of the decay products of Τ-meson is considered in par.4: a comparison with the spectrum calculated on the basis of the statistical factors does not allow any definite conclusion to be reached about the possible existence of correlations among the three decay products on account of the very poor statistics available. Finally in par.5 the ratio Τ-mesons/π-mesons coming to rest in the emulsions is considered. A comparison is made between the values of this ratio at balloon and at mountain altitudes.