Author Archive

The Pierre Auger Observatory measures the longitudinal air shower profile of ultra high energy cosmic rays which gives information on composition and hadronic interaction properties. Eun-Joo Ahn and colleagues use this data to obtain the proton-air cross section. Preliminary results show a surprising rise in the cross section with energy, which is not predicted by… More »


A common explanation for the observed acceleration of the Universe is a scalar field (i.e., scalar particles). However, experiments such as tests of gravity and measurements of fundamental constants place stringent constraints on such particles. At this time there are only three classes of scalar particles that can simultaneously accelerate the Universe and be consistent… More »

FCPA Research Associate Jiangang Hao has provided a new way to view galaxy clusters taken from the Sloan Digital Sky Survey data set. He created color images and added them to the ‘sky’ mode of the popular Google Earth application, providing a highly interactive environment for visualizing the sky. You can now fly through galaxy… More »