Fluctuations of Xmax and Primary Particle Mass Composition in the Range of Energy 5 10^{17} - 3 10^{19} ev by Yakutsk Data

Abstract

The experimental distributions of $\Xmax$ obtained with the Yakutsk EAS array at fixed energies of $5\times 10^{17}$, $1\times 10^{18}$ and $5\times 10^{18}$ eV are analysed. A recent version of the QGSJET model is used as a tool of our analysis. In the framework of this model, the most adequate mass composition of primary particles satisfying the experimental data on $\Xmax$ is selected.

19th European Cosmic Ray Symposium, Aug 30 - Sep 3 2004, Florence, Italy. 3 pages, 1 figure. Submitted for publication in International Journal of Modern Physics A