8 research outputs found
Shining Light on the Scotogenic Model: Interplay of Colliders and Cosmology
In the framework of the scotogenic model, which features radiative generation
of neutrino masses, we explore light dark matter scenario. Throughout the paper
we chiefly focus on keV-scale dark matter which can be produced either via
freeze-in through the decays of the new scalars, or from the decays of
next-to-lightest fermionic particle in the spectrum, which is produced through
freeze-out. The latter mechanism is required to be suppressed as it typically
produces a hot dark matter component. Constraints from BBN are also considered
and in combination with the former production mechanism they impose the dark
matter to be light. For this scenario we consider signatures at High Luminosity
LHC and proposed future hadron and lepton colliders, namely FCC-hh and CLIC,
focusing on searches with two leptons and missing energy as a final state.
While a potential discovery at High Luminosity LHC is in tension with limits
from cosmology, the situation greatly improves for future colliders.Comment: 28 pages, 11 figures, matches published versio
The new νMSM (ννMSM): radiative neutrino masses, keV-scale dark matter and viable leptogenesis with sub-TeV new physics
Abstract We study the scenario in which the Standard model is augmented by three generations of right-handed neutrinos and a scalar doublet. The newly introduced fields share an odd charge under a â¤2 parity symmetry. This model, commonly known as âScotogenicâ, was designed to provide a mechanism for active neutrino mass generation as well as a viable dark matter candidate. In this paper we consider a scenario in which the dark matter particle is at the keV-scale. Such particle is free from X-ray limits due to the unbroken parity symmetry that forbids the mixing between active and right-handed neutrinos. The active neutrino masses are radiatively generated from the new scalars and the two heavier right-handed states with âź O (100) GeV masses. These heavy fermions can produce the observed baryon asymmetry of the Universe through the combination of Akhmedov-Rubakov-Smirnov mechanism and recently proposed scalar decays. To the best of our knowledge, this is the first time that these two mechanisms are shown to be successful in any radiative model. We identify the parameter space where the successful leptogenesis is compatible with the observed abundance of dark matter as well as the measurements from the neutrino oscillation experiments. Interestingly, combining dark matter production and successful leptogenesis gives rise to strict limits from big bang nucleosynthesis which do not allow the mass of dark matter to lie above âź 10 keV, providing a phenomenological hint for considered low-scale dark matter. By featuring the keV-scale dark matter free from stringent X-ray limits, successful baryon asymmetry generation and non-zero active neutrino masses, the model is a direct analogue to the νMSM model proposed by Asaka, Blanchet and Shaposhnikov. Therefore we dub the presented framework as âThe new νMSMâ abbreviated as ννMSM