The search for primary particle tracks in nucleon-nucleus interactions with gamma ray energy ΣE_γ ≥ 3 TeV registered in stratospheric X-ray emulsion chambers using data of the RUNJOB experiment

P.N. Lebedev Physical Institute of RAS, 53 Leninskiy Prospekt, Moscow 119991, Russia

^a e-mail: zayar@sci.lebedev.ru

Published online: 26 June 2017

Abstract

We present here the result of a retreatment of data from the RUNJOB (RUssia-Nippon JOint Balloon) experiment of nucleon-nucleus interactions registered in stratospheric X-ray emulsion chambers (REC) using a new method for searching and tracing of galactic particles in nuclear emulsions. In about halfcof these interactions (∼ 50) recorded in REC RUNJOB‘96-3B, RUNJOB‘97-6A and RUNJOB‘99-11A,B with energy released in the electromagnetic component ΣE_γ ≥ 3 TeV and ΣE_γ ≥ 5 TeV respectively, single charged particle tracks are not found within the search area defined individually by the particle track location accuracy. The absence of primary proton tracks is consistent with the original treatment of the RUNJOB experimental data. There is a difference in the zenith angular distribution for two groups of events in which a single charged particle track is observed or absent. The average penetration depth of the primary particles in REC to the interaction vertex in the zenith angle range from 60^∘ to 79^∘ differs by a factor two for these groups.