Studies of an air-shower imaging system for the detection of ultrahigh-energy neutrinos

Abstract

Efforts to detect ultrahigh energy neutrinos are driven by several objectives: What is the origin of astrophysical neutrinos detected with IceCube? What are the sources of ultrahigh energy cosmic rays? Do the ANITA detected events point to new physics? Shedding light on these questions requires instruments that can detect neutrinos above 10 7 GeV with sufficient sensitivity -a daunting task. While most ultrahigh energy neutrino experiments are based on the detection of a radio signature from shower particles following a neutrino interaction, we believe that the detection of Cherenkov and fluorescence light from shower particles is an attractive alternative. Imaging air showers with Cherenkov and fluorescence light is a technique that is successfully used in several ultrahigh energy cosmic ray and very-high energy gamma-ray experiments. We performed a case study of an air-shower imaging system for the detection of earth-skimming tau neutrinos. The detector configuration we consider consists of an imaging system that is located on top of a mountain and is pointed at the horizon. From the results of this study we conclude that a sensitivity of 3 · 10 −9 GeV cm −2 s −1 sr −1 can be achieved at 2 · 10 8 GeV with a relatively small and modular system after three years of observation. In this presentation we discuss key findings of our study and how they translate into design requirements for an imaging system we dub Trinity.

Open Questions in Cosmic-Ray Research at Ultrahigh Energies

“…POEMMA (Olinto et al, 2018) will also detect tau neutrinos, by observing the Cherenkov radiation produced by upward-going tau decays (Neronov et al, 2017). Trinity (Otte, 2018), an Earth-based imaging telescope experiment, will detect air showers induced by taus or tau neutrinos by observing the Cherenkov or fluorescence light produced by the EAS.…”

Cosmic tau neutrino detection via Cherenkov signals from air showers from Earth-emerging taus

“…The unique nature of modeling the optical Cherenkov signal induced by upward-moving EASs and measuring the signal using a space-based instrument motivates this philosophy as a well-defined initial simulation. This traditional modeling approach also offers a method to assess the use of simulation packages such as CORSIKA [113] that were developed for groundbased measurements but require significant modifications to adapt their use for upward-moving rather than downgoing EAS modeling [43,44]. A detailed atmospheric model is required to define the EAS development, the beamed Cherenkov light emission and the Cherenkov light attenuation based on the optical depth between the EAS and observation point.…”

“…Several sub-orbital (EUSO-SPB2, [70]), space-based (CHANT, [50]; POEMMA, [71]), and ground-based (Trinity, [44]) instruments have been proposed to search for EASs from Earth-skimming tau neutrinos via optical Cherenkov radiation, which would allow for sensitivity to neutrino energies above ∼ 10 PeV, even though the duty cycle for optical Cherenkov is ∼ 20% (compared to ∼ 100% for radio). POEMMA, the Probe Of Extreme Multi-Messenger Astrophysics, is a NASA probeclass mission under study that will detect UHECRs and VHE neutrinos from space [71].…”

Prospects for high-elevation radio detection of 0>10 PeV tau neutrinos

“…A detector at high elevation with a clear view of the horizon has an acceptance that rises with detector height h 3/2 [23], increasing the overall sensitivity per station significantly compared to antennas on the ground. Other proposed experiments like the optical experiments ASHRA-NTA [24] and TRINITY [25] and the radio experiment TAROGE [26] plan to exploit the high-elevation concept; however, this study presumes the use of a beamformer radio array. The use of beamformer arrays is motivated by their improved trigger sensitivity [27,28], and real-time rejection of backgrounds due to radio frequency interference (RFI) using coarse pointing at the trigger level.…”