Probing sub-eV Dark Matter decays with PTOLEMY

Journal of Cosmology and Astroparticle Physics, vol. 2021, pp. 089

Abstract

Abstract When the Dark Matter mass is below the eV-scale, its cosmological occupation number exceeds the ones of photons from the cosmic microwave background as well as of relic neutrinos. If such Dark Matter decays to pairs of neutrinos, it implies that experiments that seek the detection of the cosmic neutrino background may as well be sensitive to this additional form of “dark radiation”. Here we study the prospects for detection taking into account various options for the forecasted performance of the future PTOLEMY experiment. From a detailed profile likelihood analysis we find that Dark Matter decays with lifetime as large as 104 Gyr or a sub-% Dark Matter fraction decaying today can be discovered. The prospects are facilitated by the distinct spectral event shape that is introduced from galactic and cosmological neutrino dark radiation fluxes. In the process we also clarify the importance of Pauli-blocking in the Dark Matter decay. The scenarios presented in this work can be considered early physics targets in the development of these instruments with relaxed demands on performance and energy resolution.

Authors 5

1. Kyrylo Bondarenko corresponding

   École Polytechnique Fédérale de Lausanne · European Organization for Nuclear Research

   Affiliation as printed

   L'Ecole polytechnique fédérale de Lausanne, Route Cantonale, 1015 Lausanne, Switzerland

   Theoretical Physics Department, CERN, 1 Esplanade des Particules, Geneva 23, CH-1211, Switzerland

2. Alexey Mikhajlovich Boyarsky corresponding Aachen Intituut-Lorentz

   Leiden University

   Affiliation as printed

   Intituut-Lorentz, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands

3. Marco Nikolic corresponding

   Austrian Academy of Sciences · Institute of High Energy Physics

   Affiliation as printed

   Institute of High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, 1050 Vienna, Austria

4. Josef Pradler corresponding

   Austrian Academy of Sciences · Institute of High Energy Physics

   Affiliation as printed

   Institute of High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, 1050 Vienna, Austria

5. Anastasia Sokolenko corresponding

   Austrian Academy of Sciences · Institute of High Energy Physics

   Affiliation as printed

   Institute of High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, 1050 Vienna, Austria