Determination of absolute neutrino masses from bursts of Z bosons in cosmic rays

Phys Rev Lett. 2002 Apr 29;88(17):171101. doi: 10.1103/PhysRevLett.88.171101. Epub 2002 Apr 16.


Ultrahigh energy neutrinos (UHEnu) scatter on relic neutrinos (Rnu) producing Z bosons, which can decay hadronically producing protons (Z burst). We compare the predicted proton spectrum with the observed ultrahigh energy cosmic ray (UHECR) spectrum and determine the mass of the heaviest Rnu via a maximum likelihood analysis. Our prediction depends on the origin of the powerlike part of the UHECR spectrum: m(nu) = 2.75(+1.28)(-0.97) eV for Galactic halo and 0.26(+0.20)(-0.14) eV for extragalactic origin. The necessary UHEnu flux should be detected in the near future.