Sensitivity of a low threshold directional detector to CNO-cycle solar neutrinos

Abstract

A first measurement of neutrinos from the CNO fusion cycle in the Sun would allow a resolution to the current solar metallicity problem. Detection of these low-energy neutrinos requires a low-threshold detector, while discrimination from radioactive backgrounds in the region of interest is significantly enhanced via directional sensitivity. This combination can be achieved in a water-based liquid scintillator target, which offers enhanced energy resolution beyond a standard water Cherenkov detector. We study the sensitivity of such a detector to CNO neutrinos under various detector and background scenarios, and draw conclusions about the requirements for such a detector to successfully measure the CNO neutrino flux. A detector designed to measure CNO neutrinos could also achieve a few-percent measurement of pep neutrinos.

Characterization of water-based liquid scintillator for Cherenkov and scintillation separation

“…The ratio of Cherenkov to scintillation light would also offer a powerful handle for particle and event classification, while a clean identification of the Cherenkov cone would be ideal for long-baseline neua e-mail: jcaravaca@berkeley.edu (corresponding author) trino physics. A detector with these capabilities would have favorable signal to background ratio across a broad spectrum of physics topics [5][6][7][8].…”

Theia: an advanced optical neutrino detector

“…Such an approach has been explored for 25-and 50kton WbLS detectors, with promising results in [81]. The approach here is based on that of [81], which is also presented in [82] and [83], with minor departures, including focusing on the specific Theia-25 and Theia-100 configurations. Sensitivity to the neutrino flux normalizations is evaluated by performing a 2D binned maximum likelihood fit in reconstructed electron energy and cos θ .…”

“…Sensitivity to the neutrino flux normalizations is evaluated by performing a 2D binned maximum likelihood fit in reconstructed electron energy and cos θ . The same simulation packages, generators and energy reconstruction methods are used as in [81]. Simulation of the neutrino interactions and radioactive decays is performed using RAT-PAC [84], a specialized simulation and analysis package employing Geant4 as the primary physics simulation software.…”

“…The energy reconstruction method is presented and evaluated in [81] and is shown to be quite robust for the energy scale considered. While the method is not a full reconstruction, it more realistically allows the folding in of geometric effects of the detector than would be achieved by a simple smearing to the Monte Carlo information.…”

Spectral photon sorting for large-scale Cherenkov and scintillation detectors

“…Independent detection of Cherenkov light allows reconstruction of event direction, which can aid in identifying solar neutrino events [16,17], classification of neutrinoless beta decay candidates against the solar neutrino background [18][19][20], or discrimination of high-energy ν e events from π 0 's, which is important for studying longbaseline neutrino oscillations. The scintillation light provides a high light yield that is critical for good energy resolution and position reconstruction.…”