Is the Electron Radiation Length Constant at High Energies?

H. D. Hansen, U. I. Uggerhøj, C. Biino, S. Ballestrero, A. Mangiarotti, P. Sona, T. J. Ketel, and Z. Z. Vilakazi

Phys. Rev. Lett. 91, 014801 – Published 1 July 2003

Abstract

Experimental results for the radiative energy loss of 149, 207, and 287 GeV electrons in a thin Ir target are presented. From the data we conclude that at high energies the radiation length increases in accordance with the Landau-Pomeranchuk-Migdal (LPM) theory and thus electrons become more penetrating the higher the energy. The increase of the radiation length as a result of the LPM effect has a significant impact on the behavior of high-energy electromagnetic showers.