Constraints on Cosmic Neutrino Fluxes from the ANITA Experiment
  We report new limits on cosmic neutrino fluxes from the test flight of the Antarctic Impulsive Transient Antenna (ANITA) experiment, which completed an 18.4 day flight of a prototype long-duration balloon payload, called ANITA-lite, in early 2004. We search for impulsive events that could be associated with ultra-high energy neutrino interactions in the ice, and derive limits that constrain several models for ultra-high energy neutrino fluxes. We rule out the long-standing Z-burst model as the source for the ultra-high energy cosmic rays. 
ANITA collaboration: S. W. Barwick, J. J. Beatty, D. Z. Besson, W. R.   Binns, B. Cai, J. M. Clem, A. Connolly, D. F. Cowen,...