Can new heavy gauge bosons be observed in ultra-high energy cosmic   neutrino events?
  A wide range of models beyond the Standard Model predict charged and neutral resonances, generically called $W'$- and $Z'$-bosons, respectively. In this paper we study the impact of such resonances on the deep inelastic scattering of ultra-high energy neutrinos as well as on the resonant charged current $\bar\nu_e e^-$ scattering (Glashow resonance). We find that the effects of such resonances can not be observed with the Pierre Auger Observatory or any foreseeable upgrade of it. 
T. Je\v{z}o, M. Klasen, F. Lyonnet, F. Montanet, I. Schienbein, M.   Tartare
hep-ph