  Ultra high energy cosmic ray (UHECR) neutrino fluxes measured in a fixed
target detector can have a scale dependence. In the usual standard model or any
extensions of this model (which are renormalizable), the effect is
observationally very small. However, this need not be the case in models with
extra-spatial dimensions, where the neutrino mass parameter can receive large
corrections due to a power-law running. Hence, the scale dependence may lead to
a measurable deviation from the standard prediction for the neutrino flux
ratio.
