[Show abstract][Hide abstract] ABSTRACT: 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 parameter space of the model
which is compatible with both collider and dark matter (DM) properties. Among
the regions compatible with these constraints, implemented through NMSSMTools,
SModelS and MadAnalysis 5, only one with a singlino lightest supersymmetric
particle (LSP) with a mass around 5 GeV can explain all the DM abundance of the
universe, while heavier mixed singlinos can only form one of the DM components.
Typical collider signatures for each region of the parameter space are
investigated. In particular, the decay of the 125 GeV Higgs into light scalars
and/or pseudoscalars and the decay of the heavy Higgs into charginos and
neutralinos, provide distinctive signatures of the model. Moreover, the
sfermion decays usually proceed through heavier neutralinos rather than
directly into the LSP, as the couplings to the singlino are suppressed. We also
show that direct detection searches are complementary to collider ones, and
that a future ton-scale detector could completely probe the region of parameter
space with a LSP mass around 65 GeV.
[Show abstract][Hide abstract] ABSTRACT: 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 quarks, the limits on the spin
dependent cross section are more stringent than those obtained in direct
detection experiments. The new functions that allow to derive those limits are
described.
[Show abstract][Hide abstract] ABSTRACT: 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, the right-handed (RH) sneutrino or
the neutralino. Limits on supersymmetric partners from LHC simplified model
searches are imposed using SModelS and allow for light squarks and gluinos.
Moreover the upper limit on the relic abundance often favours scenarios with
long-lived particles. Searches for a Z' at the LHC remain the most unambiguous
probes of this model. Interestingly, the D-term contributions to the sfermion
masses allow to explain the anomalous magnetic moment of the muon in specific
corners of the parameter space with light smuons or left-handed (LH)
sneutrinos. We finally emphasize the interplay between direct searches for dark
matter and LHC simplified model searches.
Journal of High Energy Physics 05/2015; 2015(9). DOI:10.1007/JHEP09(2015)151 · 6.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: 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 as well as semi-annihilation is
presented. Both DM signals in direct and indirect detection are computed as
well. An extension of the standard model with two scalar doublets and a singlet
is used as an example.
[Show abstract][Hide abstract] ABSTRACT: We study the dark matter from an inert doublet and a complex scalar singlet stabilized by ZN symmetries. This field content is the minimal one that allows dimensionless semi-annihilation couplings for N > 2. We consider explicitly the Z3 and Z4 cases and take into account constraints from perturbativity, unitarity, vacuum stability, necessity for the electroweak ZN preserving vacuum to be the global minimum, electroweak precision tests, upper limits from direct detection and properties of the Higgs boson. Co-annihilation and semi-annihilation of dark sector particles as well as dark matter conversion significantly modify the cosmic abundance and direct detection phenomenology.
Journal of Cosmology and Astroparticle Physics 06/2014; 2014(06):021-021. DOI:10.1088/1475-7516/2014/06/021 · 5.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We present the activities of the "New Physics" working group for the "Physics
at TeV Colliders" workshop (Les Houches, France, 3--21 June, 2013). Our report
includes new computational tool developments, studies of the implications of
the Higgs boson discovery on new physics, important signatures for searches for
natural new physics at the LHC, new studies of flavour aspects of new physics,
and assessments of the interplay between direct dark matter searches and the
LHC.
Les Houches Workshop Physics at TeV Colliders:, Les Houches, France, 2013; 05/2014
[Show abstract][Hide abstract] ABSTRACT: We study the dark matter from an inert doublet and a complex scalar singlet
stabilized by $\mathbb{Z}_N$ symmetries. This field content is the minimal one
that allows dimensionless semi-annihilation couplings for $N > 2$. We consider
explicitly the $\mathbb{Z}_3$ and $\mathbb{Z}_4$ cases and take into account
constraints from perturbativity, unitarity, vacuum stability, necessity for the
electroweak $\mathbb{Z}_N$ preserving vacuum to be the global minimum,
electroweak precision tests, upper limits from direct detection and properties
of the Higgs boson. Co-annihilation and semi-annihilation of dark sector
particles as well as dark matter conversion significantly modify the cosmic
abundance and direct detection phenomenology.
[Show abstract][Hide abstract] ABSTRACT: These lecture notes describe the micrOMEGAs code for the calculation of Dark
Matter observables in extensions of the standard model.
[Show abstract][Hide abstract] ABSTRACT: These lecture notes describe the micrOMEGAs package for the calculation
of Dark Matter observables in extensions of the standard model.
[Show abstract][Hide abstract] ABSTRACT: We study a simple model that can give rise to isospin-violating interactions
of Dirac fermion asymmetric dark matter to protons and neutrons through the
interference of a scalar and U(1)$'$ gauge boson contribution. The model can
yield a large suppression of the elastic scattering cross section off Xenon
relative to Silicon thus reconciling CDMS-Si and LUX results while being
compatible with LHC findings on the 126 GeV Higgs, electroweak precision tests
and flavour constraints.
Journal of Cosmology and Astroparticle Physics 10/2013; 2014(02). DOI:10.1088/1475-7516/2014/02/020 · 5.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This discovery of the Higgs boson last year has created new possibilities for
testing candidate theories for explaining physics beyond the Standard Model.
Here we explain the ways in which new physics can leave its marks in the
experimental Higgs data, and how we can use the data to constrain and compare
different models. In this proceedings paper we use two models, Minimal
Universal Extra Dimensions and the 4D Composite Higgs model, as examples to
demonstrate the technique.
[Show abstract][Hide abstract] ABSTRACT: micrOMEGAs is a code to compute dark matter observables in generic extensions
of the standard model. This new version of micrOMEGAs is a major update which
includes a generalization of the Boltzmann equations to accommodate models with
asymmetric dark matter or with semi-annihilation and a first approach to a
generalization of the thermodynamics of the Universe in the relic density
computation. Furthermore a switch to include virtual vector bosons in the final
states in the annihilation cross sections or relic density computations is
added. Effective operators to describe loop-induced couplings of Higgses to
two-photons or two-gluons are introduced and reduced couplings of the Higgs are
provided allowing for a direct comparison with recent LHC results. A module
that computes the signature of DM captured in celestial bodies in neutrino
telescopes is also provided. Moreover the direct detection module has been
improved as concerns the implementation of the strange "content" of the
nucleon. New extensions of the standard model are included in the distribution.
[Show abstract][Hide abstract] ABSTRACT: micrOMEGAs calculates the properties of cold dark matter in a generic
model of particle physics. First developed to compute the relic density
of dark matter, the code also computes the rates for dark matter direct
and indirect detection. The code provides the mass spectrum,
cross-sections, relic density and exotic fluxes of gamma rays, positrons
and antiprotons. The propagation of charged particles in the Galactic
halo is handled with a module that allows to easily modify the
propagation parameters. The cross-sections for both spin dependent and
spin independent interactions of WIMPS on protons are computed
automatically as well as the rates for WIMP scattering on nuclei in a
large detector. Annihilation cross-sections of the dark matter candidate
at zero velocity, relevant for indirect detection of dark matter, are
computed automatically, and the propagation of charged particles in the
Galactic halo is also handled.
[Show abstract][Hide abstract] ABSTRACT: We study the production and decay of charged scalars, eta^\pm, in the context
of a CP-Violating Inert-Doublet Model. The model is an extended version of the
Inert Doublet Model with an extra Higgs doublet and provides new sources of CP
violation and a dark matter candidate. As compared with the 2HDM, the particle
spectrum contains two additional neutral scalars and a charged pair. These
particles are subject to a Z_2 symmetry, but can be pair-produced in hadronic
collisions. If a charged scalar is included in the pair, it decays to the
stable dark-matter candidate (i.e., the lightest neutral inert scalar) plus
Standard Model matter that consists of either two jets or a single lepton (from
a virtual or real W or Z) plus missing transverse energy. Since the single
production channel is available only at hadronic colliders, we consider the
Large Hadron Collider environment, hence we discuss experimental perspectives
and possible hallmarks of the model, such as events with a displaced vertex.
Journal of High Energy Physics 02/2013; 2013(4). DOI:10.1007/JHEP04(2013)040 · 6.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We consider the minimal scalar singlet dark matter stabilised by a $Z_3$
symmetry. Due to the cubic term in the scalar potential, semi-annihilations,
besides annihilations, contribute to the dark matter relic density. Unlike in
the $Z_2$ case, the dark matter spin independent direct detection cross section
is no more linked to the annihilation cross section. We study the extrema of
the potential and show that a too large cubic term would break the $Z_3$
symmetry spontaneously, implying a lower bound on the direct detection cross
section, and allowing the whole parameter space to be tested by XENON1T. In a
small region of the parameter space the model can avoid the instability of the
standard model vacuum up to the unification scale. If the semi-annihilations
are large, however, new physics will be needed at TeV scale because the model
becomes non-perturbative. The singlet dark matter mass cannot be lower than
53.8 GeV due to the constraint from Higgs boson decay into dark matter.
Journal of Cosmology and Astroparticle Physics 11/2012; 2013(01). DOI:10.1088/1475-7516/2013/01/022 · 5.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Searches for Dark Matter (DM) particles with indirect detection techniques
have reached important milestones with the precise measurements of the
anti-proton and gamma-ray spectra, notably by the PAMELA and FERMI-LAT
experiments. While the gamma-ray results have been used to test the thermal
Dark Matter hypothesis and constrain the Dark Matter annihilation cross section
into Standard Model (SM) particles, the anti-proton flux measured by the PAMELA
experiment remains relatively unexploited. Here we show that the latter can be
used to set a constraint on the neutralino-chargino mass difference. To
illustrate our point we use a Supersymmetric model in which the gauginos are
light, the sfermions are heavy and the Lightest Supersymmetric Particle (LSP)
is the neutralino. In this framework the W^+ W^- production is expected to be
significant, thus leading to large anti-proton and gamma-ray fluxes. After
determining a generic limit on the Dark Matter pair annihilation cross section
into W^+ W^- from the anti-proton data only, we show that one can constrain
scenarios in which the neutralino-chargino mass difference is as large as ~ 20
GeV for a mixed neutralino (and intermediate choices of the anti-proton
propagation scheme). This result is consistent with the limit obtained by using
the FERMI-LAT data. As a result, we can safely rule out the pure wino
neutralino hypothesis if it is lighter than 450 GeV and constitutes all the
Dark Matter.
Journal of Cosmology and Astroparticle Physics 08/2012; 2012(11). DOI:10.1088/1475-7516/2012/11/028 · 5.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We present version 3.4 of the CalcHEP software package which is designed for
effective evaluation and simulation of high energy physics collider processes
at parton level.
The main features of CalcHEP are the computation of Feynman diagrams,
integration over multi-particle phase space and event simulation at parton
level. The principle attractive key-points along these lines are that it has:
a) an easy startup even for those who are not familiar with CalcHEP; b) a
friendly and convenient graphical user interface; c) the option for a user to
easily modify a model or introduce a new model by either using the graphical
interface or by using an external package with the possibility of cross
checking the results in different gauges; d) a batch interface which allows to
perform very complicated and tedious calculations connecting production and
decay modes for processes with many particles in the final state.
With this features set, CalcHEP can efficiently perform calculations with a
high level of automation from a theory in the form of a Lagrangian down to
phenomenology in the form of cross sections, parton level event simulation and
various kinematical distributions.
In this paper we report on the new features of CalcHEP 3.4 which improves the
power of our package to be an effective tool for the study of modern collider
phenomenology.
[Show abstract][Hide abstract] ABSTRACT: Large Hadron Collider (LHC) searches for the SM Higgs boson provide a
powerful limit on models involving Universal Extra Dimensions (UED) where the
Higgs production is enhanced. We have evaluated all one-loop diagrams for Higgs
production from gluon fusion and decay to two photons within "minimal" UED
(mUED), independently confirming previous results, and we have evaluated
enhancement factors for Higgs boson production and decay over the mUED
parameter space. Using these we have derived limits on the parameter space,
combining data from both ATLAS and CMS collaborations for the most recent 7 TeV
and 8 TeV LHC data. We have performed a rigorous statistical combination of
several Higgs boson search channels which is important because mUED signatures
from the Higgs boson are not universally enhanced.
We have found that 1/R < 500 GeV is excluded at 95% CL, while for larger 1/R
only a very narrow (\pm1-4 GeV) mass window around m_h = 125 GeV and another
window (up to 2 GeV wide for 1/R > 1000 GeV) around m_h = 118 GeV are left. The
latter is likely to be excluded as more data becomes available whereas the
region around 125 GeV is where the recently discovered Higgs-like particle was
observed and therefore where the exclusion limit is weaker.
It is worth stressing that mUED predicts an enhancement for all channels for
Higgs production by gluon fusion and decay while the vector boson fusion
process WW/ZZ -> h -> AA is generically suppressed and WW/ZZ -> h -> WW*/ZZ* is
standard. Therefore, as more 8 TeV LHC data becomes available, the information
on individual Higgs boson production and decay processes provided by the CMS
and ATLAS experiments can be effectively used to favour mUED or exclude it
further.
[Show abstract][Hide abstract] ABSTRACT: We study the impact of semi-annihilations x_i x_j <-> x_k X, where x_i is any
dark matter and X is any standard model particle, on dark matter phenomenology.
We formulate minimal scalar dark matter models with an extra doublet and a
complex singlet that predict non-trivial dark matter phenomenology with
semi-annihilation processes for different discrete Abelian symmetries Z_N, N>2.
We implement two such example models with Z_3 and Z_4 symmetry in micrOMEGAs
and work out their phenomenology. We show that both semi-annihilations and
annihilations involving only particles from two different dark matter sectors
significantly modify the dark matter relic abundance in this type of models. We
also study the possibility of dark matter direct detection in XENON100 in those
models.
Journal of Cosmology and Astroparticle Physics 04/2012; 2012(04):010-010. DOI:10.1088/1475-7516/2012/04/010 · 5.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We present the activities of the "New Physics" working group for the "Physics
at TeV Colliders" workshop (Les Houches, France, 30 May-17 June, 2011). Our
report includes new agreements on formats for interfaces between computational
tools, new tool developments, important signatures for searches at the LHC,
recommendations for presentation of LHC search results, as well as additional
phenomenological studies.
Les Houches Workshop Physics at TeV Colliders:, Les Houches, France, 2011; 03/2012