Mass Composition Working Group Report at UHECR-2012

Understand

We present a summary of the measurements of mass sensitive parameters at the highest cosmic ray energies done by several experiments.

• The Xmax distribution as a function of energy has been measured with fluorescence telescopes by the HiRes, TA and Auger experiments and with Cherenkov light detectors by Yakutsk.
• The <Xmax> or the average mass (<lnA>) has been also inferred using ground detectors, such as muon and water Cherenkov detectors.
• We discuss the different data analyses elaborated by each collaboration in order to extract the relevant information.