scholarly journals Shining light on the scotogenic model: interplay of colliders and cosmology

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Sven Baumholzer ◽  
Vedran Brdar ◽  
Pedro Schwaller ◽  
Alexander Segner
Keyword(s):  
Dark Matter ◽  
Neutrino Masses ◽  
Production Mechanism ◽  
High Luminosity ◽  
Missing Energy ◽  
Final State ◽  
Lepton Colliders ◽  
Matter Component ◽  
Freeze Out

Abstract 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.

scholarly journals Cosmological baryon transfer in the simba simulations

2019 ◽  
Vol 491 (4) ◽  
pp. 6102-6119 ◽  
Author(s):  
Josh Borrow ◽  
Daniel Anglés-Alcázar ◽  
Romeel Davé
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Large Scale ◽  
Initial Conditions ◽  
Mass Range ◽  
Gas Content ◽  
Final State ◽  
Cosmological Simulations ◽  
Baryon Transfer ◽  
Matter Component

ABSTRACT We present a framework for characterizing the large-scale movement of baryons relative to dark matter in cosmological simulations, requiring only the initial conditions and final state of the simulation. This is performed using the spread metric that quantifies the distance in the final conditions between initially neighbouring particles, and by analysing the baryonic content of final haloes relative to that of the initial Lagrangian regions (LRs) defined by their dark matter component. Applying this framework to the simba cosmological simulations, we show that 40 per cent (10 per cent) of cosmological baryons have moved $\gt 1\, h^{-1}\, {\rm Mpc}{}$ ($3\, h^{-1}\, {\rm Mpc}{}$) by z = 0, primarily due to entrainment of gas by jets powered by an active galactic nucleus, with baryons moving up to $12\, h^{-1}\, {\rm Mpc}{}$ away in extreme cases. Baryons decouple from the dynamics of the dark matter component due to hydrodynamic forces, radiative cooling, and feedback processes. As a result, only 60 per cent of the gas content in a given halo at z = 0 originates from its LR, roughly independent of halo mass. A typical halo in the mass range Mvir = 1012–1013 M⊙ only retains 20 per cent of the gas originally contained in its LR. We show that up to 20 per cent of the gas content in a typical Milky Way-mass halo may originate in the region defined by the dark matter of another halo. This inter-Lagrangian baryon transfer may have important implications for the origin of gas and metals in the circumgalactic medium of galaxies, as well as for semi-analytic models of galaxy formation and ‘zoom-in’ simulations.

scholarly journals Inverse Seesaw, dark matter and the Hubble tension

2021 ◽  
Vol 81 (10) ◽  
Author(s):  
E. Fernandez-Martinez ◽  
M. Pierre ◽  
E. Pinsard ◽  
S. Rosauro-Alcaraz
Keyword(s):  
Dark Matter ◽  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Degrees Of Freedom ◽  
Lepton Number ◽  
Neutrino Masses ◽  
Sterile Neutrinos ◽  
Seesaw Mechanism ◽  
The Universe ◽  
Matter Component

AbstractWe consider the inverse Seesaw scenario for neutrino masses with the approximate Lepton number symmetry broken dynamically by a scalar with Lepton number two. We show that the Majoron associated to the spontaneous symmetry breaking can alleviate the Hubble tension through its contribution to $$\Delta N_\text {eff}$$ Δ N eff and late decays to neutrinos. Among the additional fermionic states required for realizing the inverse Seesaw mechanism, sterile neutrinos at the keV-MeV scale can account for all the dark matter component of the Universe if produced via freeze-in from the decays of heavier degrees of freedom.

scholarly journals Loop-generated neutrino masses in composite Higgs models

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Giacomo Cacciapaglia ◽  
Martin Rosenlyst
Keyword(s):  
Dark Matter ◽  
Neutrino Masses ◽  
Composite Higgs ◽  
Partial Compositeness ◽  
Freeze Out

Abstract We present a composite scotogenic model for neutrino masses, which are generated via loops of ℤ2-odd composite scalars. We consider three different approaches to the couplings of the neutrinos (including three right-handed singlets) and the composite sector: ETC-like four-fermion interactions, fundamental partial compositeness and fermion partial compositeness. In all cases, the model can feature sizeable couplings and remain viable with respect to various experimental constraints if the three ℤ2-odd right-handed neutrinos have masses between the TeV and the Planck scales. Additionally, the lightest ℤ2-odd composite scalar may play the role of Dark Matter, either via thermal freeze-out or as an asymmetric relic. This mechanism can be featured in a variety of models based on vacuum misalignment. For concreteness, we demonstrate it in a composite two-Higgs scheme based on the coset SU(6)/Sp(6).

scholarly journals Searching in 2-Dimensional mass space for final states with 2 invisible particles

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
G. Anagnostou
Keyword(s):  
Dark Matter ◽  
Search Method ◽  
Final States ◽  
Missing Energy ◽  
Final State ◽  
True Nature ◽  
Mass Distributions ◽  
Bump Hunting ◽  
Related Distribution ◽  
Proof Of Principle

Abstract A method to search for particles of unknown masses in final states with two invisible particles is presented. Searching for final states with missing energy is a challenging task usually performed in the tail of a missing energy related distribution. The search method proposed is based on a 2-Dimensional mass reconstruction of the final state with two invisible particles. Thus, a bump hunting is possible, allowing a stronger signal versus background discrimination. Parameters of the new theory can be extracted from the mass distributions, a valuable step towards understanding its true nature. The proof of principle is based on the existing SM top pairs in their dilepton final state. The method is applicable in many interesting searches at the LHC, including dark matter candidates or heavy top partners.

scholarly journals Gravitational wave signals of dark matter freeze-out

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Danny Marfatia ◽  
Po-Yan Tseng
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Gravitational Waves ◽  
Order Phase Transition ◽  
First Order ◽  
Stochastic Background ◽  
First Order Phase Transition ◽  
Relic Abundance ◽  
First Order Phase ◽  
Freeze Out

Abstract We study the stochastic background of gravitational waves which accompany the sudden freeze-out of dark matter triggered by a cosmological first order phase transition that endows dark matter with mass. We consider models that produce the measured dark matter relic abundance via (1) bubble filtering, and (2) inflation and reheating, and show that gravitational waves from these mechanisms are detectable at future interferometers.

scholarly journals Dark matter freeze-in from semi-production

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Andrzej Hryczuk ◽  
Maxim Laletin
Keyword(s):  
Dark Matter ◽  
Early Universe ◽  
Cross Section ◽  
Thermal Equilibrium ◽  
Indirect Detection ◽  
Production Mechanism ◽  
Number Density ◽  
Matter Production ◽  
Relic Density ◽  
Standard Formalism

Abstract We study a novel dark matter production mechanism based on the freeze-in through semi-production, i.e. the inverse semi-annihilation processes. A peculiar feature of this scenario is that the production rate is suppressed by a small initial abundance of dark matter and consequently creating the observed abundance requires much larger coupling values than for the usual freeze-in. We provide a concrete example model exhibiting such production mechanism and study it in detail, extending the standard formalism to include the evolution of dark matter temperature alongside its number density and discuss the importance of this improved treatment. Finally, we confront the relic density constraint with the limits and prospects for the dark matter indirect detection searches. We show that, even if it was never in full thermal equilibrium in the early Universe, dark matter could, nevertheless, have strong enough present-day annihilation cross section to lead to observable signals.

scholarly journals Dark matter candidates in a type-II radiative neutrino mass model

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Roberto A. Lineros ◽  
Mathias Pierre
Keyword(s):  
Dark Matter ◽  
Neutral Particle ◽  
Matter Density ◽  
Indirect Detection ◽  
Dark Matter Candidate ◽  
Neutrino Masses ◽  
Type Ii ◽  
Mass Model ◽  
Direct And Indirect Detection

Abstract We explore the connection between Dark Matter and neutrinos in a model inspired by radiative Type-II seessaw and scotogenic scenarios. In our model, we introduce new electroweakly charged states (scalars and a vector-like fermion) and impose a discrete ℤ2 symmetry. Neutrino masses are generated at the loop level and the lightest ℤ2-odd neutral particle is stable and it can play the role of a Dark Matter candidate. We perform a numerical analysis of the model showing that neutrino masses and flavour structure can be reproduced in addition to the correct dark matter density, with viable DM masses from 700 GeV to 30 TeV. We explore direct and indirect detection signatures and show interesting detection prospects by CTA, Darwin and KM3Net and highlight the complementarity between these observables.

scholarly journals Dark Matter Freeze-Out via Catalyzed Annihilation

2021 ◽  
Vol 127 (6) ◽  
Author(s):  
Chuan-Yang Xing ◽  
Shou-hua Zhu
Keyword(s):  
Dark Matter ◽  
Freeze Out

scholarly journals Sterile Neutrinos as Dark Matter: Alternative Production Mechanisms in the Early Universe

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 264
Author(s):  
Daniel Boyanovsky
Keyword(s):  
Dark Matter ◽  
Distribution Function ◽  
Kinetic Equation ◽  
Standard Model ◽  
Early Universe ◽  
Quantum Kinetic Equation ◽  
Sterile Neutrinos ◽  
The Standard Model ◽  
Production Mechanisms ◽  
Freeze Out

We study various production mechanisms of sterile neutrinos in the early universe beyond and within the standard model. We obtain the quantum kinetic equations for production and the distribution function of sterile-like neutrinos at freeze-out, from which we obtain free streaming lengths, equations of state and coarse grained phase space densities. In a simple extension beyond the standard model, in which neutrinos are Yukawa coupled to a Higgs-like scalar, we derive and solve the quantum kinetic equation for sterile production and analyze the freeze-out conditions and clustering properties of this dark matter constituent. We argue that in the mass basis, standard model processes that produce active neutrinos also yield sterile-like neutrinos, leading to various possible production channels. Hence, the final distribution function of sterile-like neutrinos is a result of the various kinematically allowed production processes in the early universe. As an explicit example, we consider production of light sterile neutrinos from pion decay after the QCD phase transition, obtaining the quantum kinetic equation and the distribution function at freeze-out. A sterile-like neutrino with a mass in the keV range produced by this process is a suitable warm dark matter candidate with a free-streaming length of the order of few kpc consistent with cores in dwarf galaxies.

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