Dark matter imprint onB8neutrino spectrum

Ilídio Lopes,Joseph Silk

doi:10.1103/physrevd.99.023008

Abstract

The next generation of solar neutrino detectors will provide a precision measure of the $^8$B electron-neutrino spectrum in the energy range from 1-15 MeV. Although the neutrino spectrum emitted by $^8$B $\beta$-decay reactions in the Sun's core is identical to the neutrino spectrum measured in the laboratory, due to vacuum and matter flavor oscillations, this spectrum will be very different from that measured on Earth by the different solar neutrino experiments. We study how the presence of dark matter (DM) in the Sun's core changes the shape of the $^8$B electron-neutrino spectrum. These modifications are caused by local variations of the electronic density and the $^8$B neutrino source, induced by local changes of the temperature, density and chemical composition. Particularly relevant are the shape changes at low and medium energy range $(E_\nu\le 10 {\; \rm MeV})$, for which the experimental noise level is expected to be quite small. If such a distortion in the $^8$B$\nu_e$ spectrum were to be observed, this would strongly hint in favor of the existence of DM in the Sun's core. The $^8$B electron-neutrino spectrum provides a complementary method to helioseismology and total neutrino fluxes for constraining the DM properties. In particular, we study the impact of light asymmetric DM on solar neutrino spectra. Accurate neutrino spectra measurements could help to determine whether light asymmetric DM exists in the Sun's core, since it has been recently advocated that this type of DM might resolve the solar abundance problem.

Highlights

Solar neutrino detectors have been one of the beacons of particle physics, both by leading the way in discovering the basic properties of particles, including the nature of neutrino flavor oscillations, and by being responsible for developing pioneering techniques in experimental neutrino detection [e.g., [1,2,3] ]
We have shown that a detailed measurement of the 8Bνe spectrum in the range from 1–15 MeV by future solar neutrino experiments will permit us to probe in great detail the core of the Sun in a search for traces of dark matter (DM)
We have shown that this type of DM diagnostic can be extended to other solar neutrino spectra, once the experimental data becomes available

Summary

INTRODUCTION

Solar neutrino detectors have been one of the beacons of particle physics, both by leading the way in discovering the basic properties of particles, including the nature of neutrino flavor oscillations, and by being responsible for developing pioneering techniques in experimental neutrino detection [e.g., [1,2,3] ]. The presence of dark matter in the Sun’s core could help solve the long-running solar composition problem [35], a discrepancy between the solar structure inferred from helioseismology and the one computed from a SSM by inputting the most up-to-date photospheric abundances [36,37] This type of diagnostic has been successfully extended to other stars, including other sun-like stars [e.g., [38,39] ] and neutron stars [40,41,42,43]. This diagnostic complements the total neutrino flux analysis This is a robust result, as the shape variation of the 8Bνe spectrum is uniquely related to the radial variation of the plasma properties in the Sun’s core, where the maximum accumulation of DM is expected to occur. This type of diagnostic is useful for testing new types of DM models [e.g., [49,50] ], which have a more pronounced impact in the core of the Sun

CURRENT STATUS OF DARK MATTER RESEARCH

DARK MATTER AND THE SUN

DARK MATTER SIGNATURE ON 8B NEUTRINO SPECTRUM

Findings

SUMMARY