Excessive production of electron pairs in low multiplicity interactions

Abstract We present six cosmic ray interactions with nuclei in which the number of materialized photons is more than twice the number expected from isospin equality among the produced π 0 , π − , and π + pions. These are the most energetic ( Σ E γ > 2 TeV) of the low multiplicity events found in the quarter-section of the JACEE-2 emulsion chamber used for this study.