Sensitivity of next-generation tritium beta-decay experiments for keV-scale sterile neutrinos

Abstract

We investigate the sensitivity of tritium β-decay experiments for keV-scale sterile neutrinos. Relic sterile neutrinos in the keV mass range can contribute both to the cold and warm dark matter content of the universe. This work shows that a large-scale tritium beta-decay experiment, similar to the KATRIN experiment that is under construction, can reach a statistical sensitivity of the active-sterile neutrino mixing of sin 2 θ ∼ 10 −8 . The effect of uncertainties in the known theoretical corrections to the tritium β-decay spectrum were investigated, and found not to affect the sensitivity significantly. It is demonstrated that controlling uncorrelated systematic effects will be one of the main challenges in such an experiment.is one of the most intriguing questions of modern physics, since the Standard Model of elementary particle physics (SM) does not provide a suitable dark matter candidate. Such a candidate should be electrically neutral, at most weakly interacting, and stable with respect to the age of the universe.Relic active neutrinos, forming hot dark matter (HDM), are firmly ruled out as the dominant dark matter component. At the time of structure formation, light neutrinos had relativistic velocities and a large free streaming length, leading to a washing-out of smallscale structures, which is in disagreement with observations [16,17]. Consequently, the most most favored candidate was thought to be a cold dark matter (CDM) particle, the so-called weakly interacting massive particle (WIMP). Its freeze-out in the early universe occurs at non-relativistic velocities, preventing the washing-out of small-scale structures. Furthermore, the existence of WIMPs is independently motivated by theories extending the SM, such as Supersymmetry [18]. WIMPs are actively sought in direct and indirect measurements, but no solid evidence for their existence yet has been reported [19].Relic sterile neutrinos, with a mass in the keV range, are a candidate for both warm and cold dark matter (WDM and CDM) [8][9][10][11][12][13][14]. WDM and CDM scenarios fit the largescale structure data equally well [20]. On the galactic scale WDM scenarios predict a smaller number of dwarf satellite galaxies and shallower galactic density profiles than CDM, resolving tensions between observations of galaxy-size objects and specific CDM model simulations [21][22][23][24][25][26][27][28][29][30][31].Astrophysical observations constrain the sterile neutrino mass m s and active-sterile mixing angle θ. A robust and model-independent lower bound on the mass of spin-one-half dark matter particles is derived by considering the phase-space density evolution of dwarf spheroidal satellites in the Milky Way, leading to a mass limit of m s >1 keV [32,33]. Another sensitive observable is the X-ray emission line at half of the neutrino mass, arising from the decay of a keV-scale sterile neutrino into an active neutrino and a photon, which can be searched for with appropriate X-ray Space Telescopes, such as XMM-Newton [34] and Chandra [35]. A combination ...

The current status of ``Troitsk nu-mass'' experiment in search for sterile neutrino

“…In this procedure all electrons have to be aligned (adiabatically collimated by magnetic field) at the spectrometer analyzing plane. The operation of the spectrometer requires the adiabatic program, including extension for the search of keV-scale sterile neutrino, will be continued at KATRIN experiment [21,22]. transport system with magnetic fields up to 8 Tesla which in turn requires superconducting magnets and cryogenic systems with circulating liquid helium.…”

Prospects for finding sterile neutrino dark matter at KATRIN

“…After the option to modify KATRIN in order to probe keV-scale neutrinos was proposed in Ref. [80], first preliminary measurements have already been made [28]. We will use here the parameters from Ref.…”

Hidden treasures: Sterile neutrinos as dark matter with miraculous abundance, structure formation for different production mechanisms, and a solution to the σ8 problem

“…Since the particle production method only affects the shape of the transfer function hear λ FS (or k FS ), and the plateau of suppression is simply the recovery of the CDM-dominated matter power spectrum, the mechanism that produces 0.4% to 1% of the dark matter as WDM is not highly important in resolving the σ 8 problem. However, as an example, the Dodelson-Widrow mechanism would predict a sterile neutrino particle mass of 0.06 keV to 0.1 keV, and a mixing angle of approximately sin 2 2θ ≈ 8 × 10 −8 to 2 × 10 −7 [3,14], which could be within the sensitivity of the tritium beta-decay experiment KATRIN [41]. For the resonant Shi-Fuller mechanism, the mixing angles of sin 2 2θ ∼ 10 −12 to ∼ 10 −7 would produce the proper density of dark matter at sterile neutrino particle mass of 0.06 keV to 0.1 keV (cf.…”