
Genevieve BélangerFrench National Centre for Scientific Research | CNRS · LAPTH
Genevieve Bélanger
PhD
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265
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Introduction
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September 1994 - present
January 1988 - September 1994
Publications
Publications (265)
In a previous publication, we studied the parameter space of the phenomenological minimal Supersymmetric standard model with a light neutralino thermal dark matter ( M χ ˜ 1 0 ≤ M h / 2 ) and observed that the recent results from the dark matter and collider experiments put strong constraints on this scenario. In this work, we present in detail the...
We consider a simple extension of the standard model with fermionic dark matter (DM) and a $Z'$ gauge boson acting as a mediator. We also assume a scenario where cosmic reheating occurs at low temperatures due to the decay of a massive inflaton into standard model states. To follow the evolution of the background and the dark sector states, we impl...
We study the connection between collider and dark matter phenomenology in the singlet extension of the Georgi-Machacek model. In this framework, the singlet scalar serves as a suitable thermal dark matter (DM) candidate. Our focus lies on the region $v_{\chi}<1$ GeV, where $v_{\chi}$ is the common vacuum expectation value of the neutral components...
We briefly review scenarios with feebly interacting massive particles (FIMPs) as dark matter candidates. The discussion covers issues with dark matter production in the early universe as well as signatures of FIMPs at the high energy and high intensity frontier as well as in astroparticle and cosmology.
We briefly review scenarios with feebly interacting particles (FIMPs) as dark matter candidates. The discussion covers issues with dark matter production in the early universe as well as signatures of FIMPs at the high energy and high intensity frontier as well as in astroparticle and cosmology.
We explore the parameter space of the phenomenological minimal supersymmetric standard model with a light neutralino thermal dark matter (mχ˜10≤mh/2) that is consistent with current collider and astrophysical constraints. We consider both positive and negative values of the higgsino mass parameter (μ). Our investigation shows that the recent experi...
A bstract
We investigate, for the first time, a scenario where the dark matter consists of three complex scalar fields that are stabilized by a single Z 7 symmetry. As an extension of the well-known scalar Higgs-portal, this Z 7 model is also subject to important restrictions arising from the relic density constraint and from direct detection exper...
A bstract
The present-day B -anomalies involving b → sμ ⁺ μ − or b → cτ − $$ \overline{\nu} $$ ν ¯ transitions can all be explained with the addition of a vector U 1 leptoquark with a mass of $$ {M}_{U_1} $$ M U 1 ≳ 1 . 8 TeV. In the scalar singlet dark matter model (SSDMM), the DM is a scalar S that couples to the Higgs via λ hS S ² |H| ² . We upd...
In scenarios with very small dark matter (DM) couplings and small mass splittings between the DM and other dark sector particles, so-called “co-scattering” or “conversion-driven freeze-out” can be the dominant mechanism for DM production. We present the inclusion of this mechanism in micrOMEGAs together with a case study of the phenomenological imp...
We investigate, for the first time, a scenario where the dark matter consists of three complex scalar fields that are stabilized by a single $Z_7$ symmetry. As an extension of the well-known scalar Higgs-portal, this $Z_7$ model is also subject to important restrictions arising from the relic density constraint and from direct detection experiments...
A bstract
We present an extension of the SM involving three triplet fermions, one triplet scalar and one singlet fermion, which can explain both neutrino masses and dark matter. One triplet of fermions and the singlet are odd under a Z 2 symmetry, thus the model features two possible dark matter candidates. The two remaining Z 2 -even triplet fermi...
We consider multicomponent dark matter in a model where one dark matter component is feebly interacting (FIMP) while the second is weakly interacting (WIMP). The model contains an inert scalar doublet and a complex scalar singlet and features a discrete Z4 symmetry. Using new features of micromegas that allow us to compute the relic density for mul...
We present an extension of the SM involving three triplet fermions, one triplet scalar and one singlet fermion, which can explain both neutrino masses and dark matter. One triplet of fermions and the singlet are odd under a $Z_2$ symmetry, thus the model features two possible dark matter candidates. The two remaining $Z_2$-even triplet fermions can...
In scenarios with very small dark matter (DM) couplings and small mass splittings between the DM and other dark sector particles, so-called "co-scattering" or "conversion-driven freeze-out" can be the dominant mechanism for DM production. We present the inclusion of this mechanism in micrOMEGAs together with a case study of the phenomenological imp...
We explore the parameter space of the phenomenological Minimal Supersymmetric Standard Model (pMSSM) with a light neutralino thermal dark matter ($m_{\tilde{\chi}_1^0} \leq m_h/2$) for both positive and negative values of the higgsino mass parameter ($\mu$) that is consistent with current collider and astrophysical constraints. Our investigation sh...
A bstract
Non-minimal simplified extensions of the Standard Model have gained considerable currency in the context of dark matter searches at the LHC, since they predict enhanced mono-Higgs and mono- W/Z signatures over large parts of the parameter space. However, these non-minimal models obviously lack the simplicity and directness of the original...
The present-day $B$-anomalies involving $b \to s \mu^+ \mu^-$ or $b \to c \tau^- {\bar\nu}$ transitions can all be explained with the addition of a vector $U_1$ leptoquark with a mass of $M_{U_1} \ge 1.8$ TeV. In the scalar singlet dark matter model (SSDMM), the DM is a scalar $S$ that couples to the Higgs via $\lambda_{hS} \, S^2|H|^2$. We update...
We consider multi-component dark matter in a model where one dark matter component is feebly interacting (FIMP) while the second is weakly interacting (WIMP). The model contains an inert scalar doublet and a complex scalar singlet and features a discrete $Z_4$ symmetry. We determine the parameter space that satisfies theoretical constraints, collid...
We consider a multicomponent dark matter model where the dark sector contains a scalar doublet and a complex scalar singlet. We impose a discrete Z4 symmetry to ensure such that the lightest component of the doublet, A, and the singlet, S, are both stable. Interactions between the dark sectors impact significantly dark matter observables, and they...
A bstract
The measured branching fractions of B -mesons into leptonic final states derived by the LHCb, Belle and BaBar collaborations hint towards the breakdown of lepton flavour universality. In this work we take at face value the so-called $$ {R}_{D^{\left(\ast \right)}} $$ R D ∗ observables that are defined as the ratios of neutral B -meson cha...
The measured branching fractions of $B$-mesons into leptonic final states derived by the LHCb collaboration hint towards the breakdown of lepton flavour universality. In this work we take at face value the so-called $R_{D^{(*)}}$ observables that are defined as the ratios of neutral $B$-meson charged-current decays into a charged $D$-meson, a charg...
Non-minimal simplified extensions of the Standard Model have gained considerable currency in the context of dark matter searches at the LHC, since they predict enhanced mono-Higgs and mono-$W/Z$ signatures over large parts of the parameter space. However, these non-minimal models obviously lack the simplicity and directness of the original simplifi...
We consider a multi-component dark matter model where the dark sector contains a scalar doublet and a complex scalar singlet. We impose a discrete $Z_4$ symmetry to ensure such that the lightest component of the doublet, $\tilde{A}$, and the singlet, $\tilde{S}$, are both stable. Interactions between the dark sectors impact significantly dark matte...
Direct detection experiments obtain 90% upper limits on the elastic scattering cross sections of dark matter with nucleons assuming point-like interactions and standard astrophysical and cosmological parameters. In this paper we provide a recasting of the limits from XENON1T, PICO-60, CRESST-III and DarkSide-50 and include them in micrOMEGAs. The c...
Unlike its minimal counterpart, the next to minimal supersymmetric Standard Model (NMSSM) allows the possibility that the lightest neutralino could have a mass as small as ∼1 GeV while still providing a significant component of relic dark matter (DM). Such a neutralino can provide an invisible decay mode to the Higgs as well. Further, the observed...
In this article we review the case for a light (<mh125∕2) neutralino and sneutrino being a viable Dark Matter (DM) candidate in Supersymmetry (SUSY). To that end we recapitulate, very briefly, three issues related to the DM which impact the discussions: calculation of DM relic density, detection of the DM in Direct and Indirect experiments and crea...
In this article we review the case for a light ($< m_{h_{125}}/2$) neutralino and sneutrino being a viable Dark Matter (DM) candidate in Supersymmetry(SUSY). To that end we recapitulate, very briefly, three issues related to the DM which impact the discussions : calculation of DM relic density, detection of the DM in Direct and Indirect experiments...
A bstract
Scenarios for multi-component scalar dark matter based on a single Z N ( N ≥ 4) symmetry are simple and well-motivated. In this paper we investigate, for the first time, the phenomenology of the Z 5 model for two-component dark matter. This model, which can be seen as an extension of the well-known singlet scalar model, features two compl...
We present a thorough analysis of the sequential freeze-in mechanism for dark matter production in the early Universe. In this mechanism the dark matter relic density results from pair annihilation of mediator particles which are themselves produced by thermal collisions of standard model particles. Below some critical value of the mediator couplin...
Scenarios for multi-component scalar dark matter based on a single $Z_N$ ($N\geq 4$) symmetry are simple and well-motivated. In this paper we investigate, for the first time, the phenomenology of the $Z_5$ model for two-component dark matter. This model, which can be seen as an extension of the well-known singlet scalar model, features two complex...
Unlike its minimal counterpart, the Next to Minimal supersymmetric Standard Model (NMSSM) allows the possibility that the lightest neutralino could have a mass as small as $\sim 1~{\rm GeV}$ while still providing a significant component of relic dark matter (DM). Such a neutralino can provide an invisible decay mode to the Higgs as well. Further, t...
We present a thorough analysis of the sequential freeze-in mechanism for dark matter production in the early universe. In this mechanism the dark matter relic density results from pair annihilation of mediator particles which are themselves produced by thermal collisions of standard model particles. Below some critical value of the mediator couplin...
This report presents the activities of the `New Physics' working group for the `Physics at TeV Colliders' workshop (Les Houches, France, 10--28 June, 2019). These activities include studies of direct searches for new physics, approaches to exploit published data to constrain new physics, as well as the development of tools to further facilitate the...
We present a class of dark matter models, in which the dark matter particle is a feebly interacting massive particle (FIMP) produced via the decay of an electrically charged and/or colored parent particle. Given the feeble interaction, dark matter is produced via the freeze-in mechanism and the parent particle is long-lived. The latter leads to int...
A bstract
We propose simple freeze-in models where the observed dark matter abundance is explained via the decay of an electrically charged and/or coloured parent particle into Feebly Interacting Massive Particles (FIMP). The parent particle is long-lived and yields a wide variety of LHC signatures depending on its lifetime and quantum numbers. We...
A bstract
The minimal supersymmetric (SUSY) standard model (MSSM) augmented by right chiral sneutrinos may lead to one such sneutrino serving as the lightest supersymmetric particle and a non-thermal dark matter candidate, especially if neutrinos have Dirac masses only. In such cases, if the lightest MSSM particle is a stau, the signal of SUSY at t...
The minimal supersymmetric (SUSY) standard model (MSSM) augmented by right chiral sneutrinos may lead to one such sneutrino serving as the lightest supersymmetric particle and a non-thermal dark matter candidate, especially if neutrinos have Dirac masses only. In such cases, if the lightest MSSM particle is a stau, the signal of SUSY at the LHC con...
We present a major upgrade of the micrOMEGAs dark matter code to compute the abundance of feebly interacting dark matter candidates through the freeze-in mechanism in generic extensions of the Standard Model of particle physics. We develop the necessary formalism in order to solve the freeze-in Boltzmann equations while making as few simplifying as...
We present a major upgrade of the micrOMEGAs dark matter code to compute the abundance of feebly interacting dark matter candidates through the freeze-in mechanism in generic extensions of the Standard Model of particle physics. We develop the necessary formalism in order to solve the freeze-in Boltzmann equations while making as few simplifying as...
In the context of searches for long-lived particles (LLP), we have shown, using several benchmarks, that objects which emerge from a secondary vertex due to the decay of an LLP at the TeV scale, are often at large angular separations with respect to the direction of the parent LLP and a fraction of the decay products can even go in the backward dir...
In contrast to the decay products ensuing from a fast moving particle which are collimated along the original direction of the parent, those from a slow moving particle are distributed over a wide region. In the context of searches for heavy long-lived particles (LLP) at the Large Hadron Collider (LHC), we quantitatively demonstrate, using a few be...
We study the decay of 125 GeV Higgs boson to a pair of lightest neutralinos in the phenomenological minimal supersymmetric standard model in the context of collider searches and astrophysical experiments. We consider the parameter space for light neutralinos that can be probed via the invisible Higgs decays and Higgsino searches at the ILC. We cons...
We present a full one-loop renormalisation of the Higgs sector of the Next-to-Minimal- Supersymmetric-Standard-Model (NMSSM) and its implementation within SloopS, a code for the automated computations of one-loop processes in theories beyond the Stan- dard Model. The present work is the sequel to the study we performed on the renor- malisation of t...
Models in which dark matter particles communicate with the visible sector through a pseudoscalar mediator are well-motivated both from a theoretical and from a phenomenological standpoint. With direct detection bounds being typically subleading in such scenarios, the main constraints stem either from collider searches for dark matter, or from indir...
We present a full one-loop renormalisation of the Higgs sector of the Next-to-Minimal- Supersymmetric-Standard-Model (NMSSM) and its implementation within SloopS, a code for the automated computations of one-loop processes in theories beyond the Stan- dard Model. The present work is the sequel to the study we performed on the renor- malisation of t...
Models in which dark matter particles communicate with the visible sector through a pseudoscalar mediator are well-motivated both from a theoretical and from a phenomenological standpoint. With direct detection bounds being typically subleading in such scenarios, the main constraints stem either from collider searches for dark matter, or from indir...
We study the decay of 125 GeV Higgs boson to light LSP neutralino in the phenomenological minimal supersymmetric standard model in the context of collider searches and astrophysical experiments. We consider the parameter space for light neutralinos that can be probed via the invisible Higgs decays and higgsino searches at the ILC. We consider the c...
We revisit a set of dark sector models, motivated by anomalies observed in B decays and the muon anomalous magnetic moment, in the light of a recently reported diphoton excess around 750 GeV. Interpreting the excess as a scalar resonance associated with the symmetry breaking sector of a dark gauge group, we show that a diphoton cross section of O(f...
This Report summarizes the results of the activities of the LHC Higgs Cross Section Working Group in the period 2014-2016. The main goal of the working group was to present the state-of-the-art of Higgs physics at the LHC, integrating all new results that have appeared in the last few years. The first part compiles the most up-to-date predictions o...
Heavy vector-like quarks coupled to a scalar $S$ will induce a coupling of this scalar to photons and/or gluons. The decay of the heavy quark into $Sq$, with $q$ being a SM quark, could provide a new search channel for heavy quarks. For illustration, we consider the case of a singlet vector-like partner of the top quark and show that it can be sear...
Heavy vector-like quarks coupled to a scalar $S$ will induce a coupling of this scalar to gluons and possibly (if electrically charged) photons. The decay of the heavy quark into $Sq$, with $q$ being a Standard Model quark, provides, if kinematically allowed, new channels for heavy quark searches. Inspired by naturalness considerations, we consider...
Results from the LHC put severe constraints on models of new physics. This includes constraints on the Higgs sector from the precise measurement of the mass and couplings of the 125 GeV Higgs boson, as well as limits from searches for other new particles. We present the procedure to use these constraints in micrOMEGAs by interfacing it to the exter...
Results from the LHC put severe constraints on models of new physics. This includes constraints on the Higgs sector from the precise measurement of the mass and couplings of the 125GeV Higgs boson, as well as limits from searches for other new particles. We present the procedure to use these constraints in micrOMEGAs by interfacing it to the extern...
Current data (LHC direct searches, Higgs mass, dark matter-related bounds) severely affect the constrained minimal SUSY standard model (CMSSM) with neutralinos as dark matter candidates. But the evidence for neutrino masses coming from oscillations requires extending the SM with at least right-handed neutrinos with a Dirac mass term. In turn, this...
Current data (LHC direct searches, Higgs mass, dark matter-related bounds) severely affect the constrained minimal SUSY standard model (CMSSM) with neutralinos as dark matter candidates. But the evidence for neutrino masses coming from oscillations requires extending the SM with at least right-handed neutrinos with a Dirac mass term. In turn, this...
We revisit a set of dark sector models, motivated by anomalies observed in $B$ decays and the muon anomalous magnetic moment, in the light of a recently reported diphoton excess around 750$\,$GeV. Interpreting the excess as a scalar resonance associated with the symmetry breaking sector of a dark gauge group, we show that a diphoton cross section o...
The comparison of the results of direct detection of dark matter, obtained with various target nuclei, requires model-dependent, or even arbitrary, assumptions. Indeed, to draw conclusions either the spin-dependent (SD) or the spin-independent (SI) interaction has to be neglected. In the light of the null results from supersymmetry searches at the...
We have completed the one-loop renormalisation of the Next-to-Minimal Supersymmetric Standard Model (NMSSM) allowing for and comparing between different renormalisation schemes. A special attention is paid to on-shell schemes. We study a variety of these schemes based on alternative choices of the physical input parameters. In this paper we present...
We have completed the one-loop renormalisation of the Next-to-Minimal Supersymmetric Standard Model (NMSSM) allowing for and comparing between different renormalisation schemes. A special attention is paid to on-shell schemes. We study a variety of these schemes based on alternative choices of the physical input parameters. In this paper we present...
The comparison of the results of direct detection of Dark Matter, obtained with various target nuclei, requires model-dependent, or even arbitrary, assumptions. Indeed, to draw conclusions either the spin-dependent (SD) or the spin-independent (SI) interaction has to be neglected. In the light of the null results from supersymmetry searches at the...
Limits on dark matter spin dependent elastic scattering cross section on
protons derived from IceCube data are obtained for different dark matter
annihilation channels using micrOMEGAs. The uncertainty on the derived limits,
estimated by using different neutrino spectra, can reach a factor two. For all
dark matter annihilation channels except for q...
If weak scale supersymmetry (SUSY) is to somehow explain the radiative
stability of the Higgs boson mass, it is likely that non-minimal variants of
SUSY models should be considered. Under the assumption that the dark matter of
the universe is comprised of neutralinos, recent limits from direct detection
experiments as well as dark matter abundance...
The new minimal supersymmetric standard model (nMSSM), a variant of the general next to minimal supersymmetric standard model (NMSSM) without Z
3 symmetry, features a naturally light singlino with a mass below 75 GeV. In light of the new constraints from LHC Run-1 on the Higgs couplings, sparticles searches and flavour observables, we define the pa...
We show that the recently reported anomalies in $b\to s\mu^+\mu^-$
transitions, as well as the long-standing $g_\mu-2$ discrepancy, can be
addressed simultaneously by a new massive abelian gauge boson with loop-induced
coupling to muons. Such a scenario typically leads to a stable dark matter
candidate with a thermal relic density close to the obse...
The discovery of a Higgs boson with a mass of 126 GeV at the LHC when
combined with the non-observation of new physics both in direct and indirect
searches imposes strong constraints on supersymmetric models and in particular
on the top squark sector. The experiments for direct detection of dark matter
have provided with yet more constraints on the...
The U(1) extended supersymmetric standard model (UMSSM) can accommodate a
Higgs boson at 125 GeV without relying on large corrections from the top/stop
sector. After imposing LHC results on the Higgs sector, on B-physics and on new
particle searches as well as dark matter constraints, we show that this model
offers two viable dark matter candidates...
A comprehensive review of physics at an e+e- Linear Collider in the energy
range of sqrt{s}=92 GeV--3 TeV is presented in view of recent and expected LHC
results, experiments from low energy as well as astroparticle physics.The
report focuses in particular on Higgs boson, Top quark and electroweak
precision physics, but also discusses several model...
Searches in final states with two leptons plus missing transverse energy,
targeting supersymmetric particles or invisible decays of the Higgs boson, were
performed during Run 1 of the LHC. Recasting the results of these analyses in
the context of the Inert Doublet Model (IDM) using MadAnalysis 5, we show that
they provide constraints on inert scala...
Weak scale supersymmetry (SUSY) remains a prime explanation for the radiative
stability of the Higgs field. A natural account of the Higgs boson mass,
however, strongly favors extensions of the Minimal Supersymmetric Standard
Model (MSSM). A plausible option is to introduce a new supersymmetric sector
coupled to the MSSM Higgs fields, whose associa...
The positron fraction in cosmic rays was found to be a steadily increasing in
function of energy, above $\sim$ 10 GeV. This behaviour is in tension with
standard astrophysical mechanisms, in which positrons are secondary particles,
produced in the interactions of primary cosmic rays during the propagation in
the interstellar medium. The observed an...
micrOMEGAs is a code to compute dark matter observables in generic extensions
of the standard model. This version of micrOMEGAs includes a generalization of
the Boltzmann equations to take into account the possibility of two dark matter
candidates. The modification of the relic density calculation to include
interactions between the two DM sectors...