Prospects for Lunar Satellite Detection of Radio Pulses from Ultrahigh Energy Neutrinos Interacting with the Moon

The Moon provides a huge effective detector volume for ultrahigh energy cosmic neutrinos, which generate coherent radio pulses in the lunar surface layer due to the Askaryan effect. In light of presently considered lunar missions, we propose radio measurements from a Moon-orbiting satellite. First systematic Monte Carlo simulations demonstrate the detectability of Askaryan pulses from neutrinos with energies above ${10}^{20}\mathrm{eV}$ at the very low fluxes predicted in different scenarios.

Figure 1

Monte Carlo simulation results for the fraction of neutrino events (energy $E_{\nu }$) above a given depth in the Moon, as detected by a tripole antenna (frequency $\nu$) in a Moon-orbiting satellite at 100 km altitude.

Figure 2

$E^2$-weighted flux of $\mathrm{UHEC}\nu$. Solid (color) curves show the projected detection limits from Eq. (3), based on 1 yr of satellite measurements with (a) a single tripole antenna and (b) a beam-filling antenna for frequencies of 100 MHz (lower set of curves) and 1000 MHz (upper set of curves). Within each set, the curves from top to bottom are for satellite altitudes $H$ of 100, 250, and 1000 km, respectively. Dashed lines show predicted fluxes from the GZK process [3] (consistent with the Waxman-Bahcall bound $5\times {10}^{-8}$ [33]), $Z$ bursts, and topological defects (TD) [30]. Thin solid lines show current flux limits from ANITA-lite [9], RICE [34], GLUE [15], and FORTE [28]. Dotted lines show predicted sensitivities for ANITA [9], LOFAR [17], and LORD [18].