Alignment phenomenon in superfamilies with energy above 400 TeV

Summary The analysis is presented of the alignment phenomenon of the most energetic particles in gamma-hadron families with energy above 400 TeV. It is shown that the effect increases with energy. At an energy of about 1000 TeV the fraction of aligned families is equal to 0.26±0.09 for carbon chambers and 0.43±0.17 for lead chambers. From the comparison with simulated families it is seen that it exceeds the background value at about 2.0 standard deviations. A possible interpretation of the phenomenon is discussed. Paper presented at the Special Session on very high-energy cosmic-ray interactions (superfamilies) of the XXIV International Cosmic-Ray Conference, Rome, August 28–September 8, 1995.