10 research outputs found
Singlet-doublet/triplet dark matter and neutrino masses
In these proceedings, we present a study of a combined singlet--doublet
fermion and triplet scalar model for dark matter (DM). Together, these models
form a simple extension of the Standard Model (SM) that can account for DM and
explain the existence of neutrino masses, which are generated radiatively.
However, this also implies the existence of lepton flavour violating (LFV)
processes. In addition, this particular model allows for gauge coupling
unification. The new fields are odd under a new symmetry to
stabilise the DM candidate. We analyse the DM, neutrino mass and LFV aspects,
exploring the viable parameter space of the model. This is done using a
numerical random scan imposing successively the neutrino mass and mixing, relic
density, Higgs mass, direct detection, collider and LFV constraints. We find
that DM in this model is fermionic for masses below about 1 TeV and scalar
above. We observe a high degree of complementarity between direct detection and
LFV experiments, which should soon allow to fully probe the fermionic DM sector
and at least partially the scalar DM sector.Comment: 4 pages, 1 figure; contribution to the 2019 EW session of the 54th
Rencontres de Moriond (summary of arXiv:1812.11133
Electroweak Phase Transition, Gravitational Waves and Dark Matter in Two Scalar Singlet Extension of The Standard Model
In this paper, the electroweak phase transition, the gravitational waves and
the dark matter issues are investigated in two scalar singlet extension of the
standard model. The detectability of the gravitational wave signals are
discussed by comparing the results with the sensitivity curves of
, , and
detectors. It is shown that the results support the recent reports on the dark
matter relic density by collaboration and the
direct detection experiment by
collaboration.Comment: 18 pages, 2 figures (4 subfigures), 4 tables, final version to match
the published versio
Investigating extended scalar sectors at current and future colliders
In this work, I briefly report on constraints that can be obtained on new
physics models that extend the scalar sector of the Standard Model (SM) of
particle physics at the LHC. I concentrate on a few simple examples which serve
to demonstrate advantages as well as possible drawbacks of current experimental searches, and comment on the discovery prospects of such models at future colliders
Singlet-doublet fermion and triplet scalar dark matter with radiative neutrino masses
We present a detailed study of a combined singlet-doublet fermion and triplet
scalar model for dark matter. These models have only been studied separately in
the past. Together, they form a simple extension of the Standard Model that can
account for dark matter and explain the existence of neutrino masses, which are
generated radiatively. This holds even if singlet-doublet fermions and triplet
scalars never contribute simultaneously to the dark matter abundance. However,
this also implies the existence of lepton flavour violating processes. In
addition, this particular model allows for gauge coupling unification. The new
fields are odd under a new symmetry to stabilise the dark matter
candidate. We analyse the dark matter, neutrino mass and lepton flavour
violation aspects both separately and in conjunction, exploring the viable
parameter space of the model. This is done using a numerical random scan
imposing successively the neutrino mass and mixing, relic density, Higgs mass,
direct detection, collider and lepton flavour violation constraints. We find
that dark matter in this model is fermionic for masses below about 1 TeV and
scalar above. The narrow mass regions found previously for the two separate
models are enlarged by their coupling. While coannihilations of the weak
isospin partners are sizeable, this is not the case for fermions and scalars
despite their often similar masses due to the relatively small coupling of the
two sectors, imposed by the small neutrino masses. We observe a high degree of
complementarity between direct detection and lepton flavour violation
experiments, which should soon allow to fully probe the fermionic dark matter
sector and at least partially the scalar dark matter sector.Comment: 24 pages, 12 figures; version accepted by and published in JHE
Review on Dark Matter Tools
Whilst the need for dark matter was established almost a century ago, only
its gravitational interaction has been confirmed so far, allowing for plethora
of models for dark matter. The Weakly Interacting Massive Particles (WIMPs)
category has received by far the biggest attention, however despite the
enormous experimental efforts, these particles remain elusive. The attention of
the community has hence moved on to investigate the dark matter landscape over
a much larger number of models with varying degrees of resemblances and
differences in their predictions. This calls for the need to organise the
various facets of dark matter models and their signatures, in order to maximise
the experimental sensitivity and to select the models which are compatible with
existing data. In this paper, I provide a short review of the most widespread
public codes capable of computing dark matter observables. In particular, I
discuss what is the status of each numerical tool in terms of: (i) capturing
the WIMP phenomenology and (ii) accounting for new trend dark sector models
that might be weakly coupled to ordinary matter and/or be strongly
self-interacting. This short review has the aim of guiding the user towards
selecting the best suited public code to confront his/her model with the
largest variety of theoretical predictions and experimental data in order to
determine the parameter space consistent with observations for his/her
favourite dark matter model.Comment: 9 pages + references; matches the published version (only few
references added) into "Tools for High Energy Physics and Cosmology"
(TOOLS2020), 2-6 Nov. 2020, IP2I Lyon, Franc
Characterizing dark matter interacting with extra charged leptons
In the context of a simplified leptophilic dark matter (DM) scenario where the mediator is a new charged fermion carrying leptonic quantum number and the DM candidate is either scalar or vector, the complementarity of different bounds is analyzed. In this framework, the extra lepton and DM are odd under a Z2 symmetry, and hence the leptonic mediator can only interact with the DM state and Standard Model leptons of various flavors. We show that there is the possibility to characterize the DM spin (scalar or vector), as well as the nature of the mediator, through a combined analysis of cosmological, flavor and collider data. We present an explicit numerical analysis for a set of benchmarks points of the viable parameter space of our scenario
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On effective field theory of dark matter
We investigate the feasibility of dark matter particles existing in the Universe as a spin- fermion using effective field theories to parametrise the higher order physics. Our goal is to determine the requirements for exclusion of such particles by direct and indirect detection. In part~\ref{part:1}, based on ref.~\cite{geytenbeek21}, we introduce a complete basis of operators up to dimension 5 for fermions that are part of singlet, doublet and triplet representation of the Standard Model electroweak symmetry group. Such particles correspond to the bino, higgsino and wino of supersymmetry models respectively. We determine the thermal relic density of particles interacting with each of our operators and show that viable thermal relics that evade experimental constraints can exist with masses as low as as 100\GeV and up to 10\TeV due to the mass splittings that arise at dimension 5. In part~\ref{part:2}, based on ref.~\cite{geytenbeek17} we further investigate the effect of fermionic dark matter that may interact through an electromagnetic dipole interaction at dimension 5 on energy transport in the Sun. In particular, we test whether the models can provide a solution to the solar abundance problem, a theoretical discrepancy between the observations of helioseismology and the theoretical Standard Solar Model. We introduce all of the necessary theoretical implementation and show that, although introducing dark matter may alleviate the tension of the solar abundance problem, the required interaction strengths are strongly ruled out by direct detection experiments.Gates Cambridg