Solar Neutrino Detection Sensitivity in DARWIN via Electron Scattering

Abstract

We detail the sensitivity of the liquid xenon (LXe) DARWIN observatory to solar neutrinos via elastic electron scattering. We find that DARWIN will have the potential to measure the fluxes of five solar neutrino components: pp, 7 Be, 13 N, 15 O and pep. The precision of the 13 N, 15 O and pep components is hindered by the double-beta decay of 136 Xe and, thus, would benefit from a depleted target. A high-statistics observation of pp neutrinos would allow us to infer the values of the weak mixing angle, sin 2 θ w , and the electron-type neutrino survival probability, P e , in the electron recoil energy region from a few keV up to 200 keV for the first time, with relative precision of 5% and 4%, respectively, at an exposure of 300 ty. An observation of pp and 7 Be neutrinos would constrain the neutrino-inferred solar luminosity down to 0.2%. A combination of all flux measurements would distinguish between the high (GS98) and low metallicity (AGS09) solar models with 2.1-2.5σ significance, independent of external measurements from other experia

Direct Detection of Dark Matter -- APPEC Committee Report

“…The upcoming generation of LXe detectors will start observing the first solar neutrino signals: irreducible low-energy NRs from 8 B neutrinos and ERs from pp and 7 Be neutrinos [241,242] that can be rejected via S2/S1-based discrimination. Multi-ton scale detectors will measure the solar pp neutrino flux to sub-percent levels [150,243].…”

“…The pp chain of nuclear reactions is the dominant energy production mechanism in the Sun, but the associated pp neutrinos are extremely difficult to detect due to their low energy 400keV . In DM detectors, on the other hand, scattering of solar pp neutrinos on electrons is the dominant neutrino-induced background at energies below ∼200 keV [253] and a sub-percent flux measurement is possible [243]. (In the case of nuclear recoils, only 8 B and hep neutrinos are relevant at recoil energies 0.1 keV [487].)…”

“…Such a measurement will be interesting in the context of the solar metallicity problem, a persistent tension between measured element abundances at the Sun's surface and predictions from solar models fitted to data from helioseismology (see [488] for a review and for further references). Some models addressing this tension predict substantially modified neutrino fluxes (for CNO neutrinos, the discrepancy between the two leading metallicity models [489] and [490] is up to 38%), which could be tested in DM detectors, see e.g., [243,491].…”

Constraints on general light mediators from PandaX-II electron recoil data

“…Indeed, the possibility of massive neutrinos with new interactions could be either confirmed or excluded by the near future direct detection dark matter experiments [3][4][5][6][7] or by the dedicated neutrino experiments.…”

“…This has lead them to put a relatively weak constraint on solar axions and anomalous neutrino magnetic moment for the relatively less exposure of 100.7 ton-days [1]. The possibility of tritium decay as the source of the excess or the possibility of any new physics or the new physics induced tritium decay will be resolved by the near future direct direction experiments with their large exposure and unprecedented low background [3][4][5][6][7].…”