PhD14 - Indirect searches for Dark Matter towards the Sun with neutrinos

Despite decades of intensive studies, observations and experiments, the nature of Dark Matter remains a mystery. Observations from galactic to cosmological scales leave little room to explanations for Dark Matter other than being a new type of particle relic from the Big Bang. The most attractive candidate for this particle is a Weakly Interacting Massive Particle (WIMP) which naturally arises in many theories beyond the Standard Model which were developed independently to address other questions like the origin of electroweak symmetry breaking or the gauge hierarchy problem.

WIMPs are searched for in variety of ways: by particle production at accelerators, by searching for signals of nuclear recoils (direct detection) and by searching for a signal from secondary products of WIMPs annihilation of decays, in particular gamma-rays and neutrinos. Such annihilation signals are looked for at sources were the WIMPs might be accumulated by gravity: in the core of the Earth or the Sun for neutrino signals; towards the galactic centre, the galactic halo, dwarf spheroidal galaxies and galaxy clusters for gamma-ray and neutrino signals. In addition, diffuse signals of WIMP annihilations can be searched for in fluxes of charged cosmic rays, mainly positrons and anti-protons.

Among those, a very promising way to identify the WIMP nature of Dark Matter is to search for an excess neutrino flux from the Sun generated by self-annihilations of WIMPs trapped inside the Sun. The high-energy neutrino flux originating from decay of annihilation products are expected to arrive on Earth and be looked for with neutrino telescopes.

The ANTARES neutrino telescope, located at 2500 m depth in the Mediterranean Sea near Toulon (France), is collecting data with its full configuration since 2008. It is the largest neutrino telescope of the Northern hemisphere, and the only one operated in sea water. Today, ANTARES detected more than 8000 neutrinos above an energy threshold of ~15 GeV, and is planning to collect data until the end of 2016.

This thesis proposal is focused on the study of indirect searches for Dark Matter towards the Sun with neutrinos, both on phenomenological aspects and experimental aspects.

In this thesis, we propose firstly to make a comprehensive review of the uncertainties on the astrophysical parameters playing a role on the capture rate of Dark Matter by the Sun, and their impact on the neutrino signal resulting from self-annihilations of WIMPs trapped in the Sun, such as the local density and the velocity distribution of Dark Matter particles in the neighborhood of the Solar System. The candidate will model the Dark Matter distribution in the MW halo through analytical assumptions and using cosmological simulations of Milky-Way like galaxies, and evaluate the resulting capture rate in the Sun.

The second aspect of this proposal is to pursue the experimental search for the indirect search for Dark Matter towards the Sun with neutrinos by exploiting the full data set of the ANTARES neutrino telescope which will take data until the end of 2016. The current analysis of this signal based on the reconstruction of muon tracks, which has been developed in the past years by the ANTARES team at CPPM, will be extended to the electron neutrino channel by adapting the algorithms recently developed within the ANTARES Collaboration to improve the reconstruction and the selection of the shower events. Due to the analysis of the full ANTARES statistics and the developments in the analysis, one can expect an improvement of almost a factor ten in the sensitivity to the solar indirect detection with neutrinos with respect to the current limits of ANTARES, leading to very competitive results with respect to other neutrino detectors or to direct detection experiments.

Finally, some studies of the performances and sensitivities for indirect search for Dark Matter with the next generation KM3NeT neutrino telescope taking into account the improvements developed for the analyses of the ANTARES data will be performed.

This work will be performed in collaboration between the ANTARES group at CPPM, specialized in the analysis of the ANTARES data as well as indirect detection of Dark Matter, and a team at LAM, specialized in Dark Matter phenomenology and in halo distribution simulations, with a close collaboration with LUPM in Montpellier.

This subject is at the rich and exciting frontier between astroparticle physics, particle physics and astrophysics. The candidate should therefore have a good background in astroparticle physics and interest in the other domains. The calculations and analyses will be developed and performed using C/C++, Root, Python and Mathemathica tools on Linux platforms.

References:

[1] A. Gould, Astrophysical Journal 321, 560 (1987)

[2] G. Jungman, M. Kamionkowski, K. Griest, Physics Report 267 (1996) 195-373.

[3] K. Choi, C. Rott, Y.Itow, JCAP 05 (2014) 049.