Orateur
M.
Robert Mutel
(University of Iowa)
Description
R.L. Mutel, T. R. Jager, K. G. Gayley
University of Iowa
We present new flux limits for UHE neutrinos derived from radio searches using a lunar target. The RESUN search used three 4-antenna sub-arrays of the Expanded Very Large Array at an observing frequency of 1.4~GHz to search for short duration Cerenkov emission from the lunar limb. Each antenna’s down-converted waveform was sampled every 10 nsec, with all pulses exceeding a 4-sigma threshold time-stamped and recorded for post-processing. For each sub-array, the data were searched for 4-antenna coincidences using differential delay windows corresponding to sources of lunar origin. We detected no coincident pulses during 250 observing hours. This implies upper limits to the differential neutrino flux $E^2dN/dE < 0.0001 EeV km$^{-2)$ s$^{-1}$ sr$^{-1}$ and < 0.00001 EeV/km2/s at 90% confidence level for isotropic and sampled point sources respectively, in the neutrino energy range $10^{20.5}$ < E(eV) < $10^{22.5}$. The isotropic flux limit is more than an order of magnitude lower than previously published upper limits for lunar searches in this energy range, and is incompatible with predicted fluxes from Z-burst models of neutrino generation.
Auteur principal
M.
Robert Mutel
(University of Iowa)
