12-20 July 2017
Asia/Seoul timezone
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BEXCO - Room F(201/202/203/204)

[CRI305] On the origin of abnormal absorption of hadron component of EAS cores in lead


  • Alexander BORISOV

Primary authors



The origin of the cosmic ray hadron excess observed in a deep uniform lead X-ray emulsion chamber (XREC) at depths larger than 70 radiation lengths is analyzed. We present preliminary experimental data on the absorption of cosmic ray hadrons in the two-storey XREC with a large air gap exposed at the Tien Shan mountains. The design of the chamber was especially invented to prove the hypothesis on a substantial increase of the charm particle production cross section with energy at E_Lab ~ 75 TeV as the main source of the darkness spot excess observed on X-ray films. Experimental data obtained with both a 2-storey XREC and a deep uniform XREC are compared with simulation results calculated with the FANSY 1.0 model. The comparison reveals a qualitative agreement between experimental and simulated data under the assumption of high values of charm particle production cross section at E_Lab ~ 75 TeV in the forward kinematic region at x_Lab > 0.1. A preliminary result of charm production cross section in the forward cone at energy E_Lab ∼ 75 TeV is discussed. Particularly, the result is compared with those of collider experiments (RHIC and LHC) obtained for kinematic central region characterizing by relatively low pseudorapidities.