24 research outputs found
micrOMEGAs4.1: two dark matter candidates
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.Comment: 13 pages, 1 figur
micrOMEGAs: Version 1.3
We present the latest version of micromegas, a code that calculates the relic
density of the lightest supersymmetric particle in the MSSM. All tree-level
processes for the annihilation of the LSP are included as well as all possible
coannihilation processes with neutralinos, charginos, sleptons, squarks and
gluinos. The cross-sections extracted from CalcHEP are calculated exactly using
loop-corrected masses and mixings as specified in the SUSY Les Houches Accord.
Relativistic formulae for the thermal average are used and care is taken to
handle poles and thresholds by adopting specific integration routines. The
input parameters can be either the soft SUSY parameters in a general MSSM or
the parameters of a SUGRA model specified at some high scale (GUT). In the
latter case, a link with Suspect, Softsusy, Spheno and Isajet allows to
calculate the supersymmetric spectrum, Higgs masses, as well as mixing
matrices. Higher-order corrections to Higgs couplings to quark pairs including
QCD as well as some SUSY corrections (deltaMb) are implemented. Routines
calculating (g-2), bsgamma and bsmumu are also included. In particular the
bsgamma routine includes an improved NLO for the SM and the charged Higgs while
the SUSY large tan(beta) effects beyond leading-order are included. This new
version also provides cross-sections for any 2->2 process as well as partial
decay widths for two-body final states in the MSSM allowing for easy simulation
at colliders.Comment: 45 page
micrOMEGAs : a tool for dark matter studies
micrOMEGAs is a tool for cold dark matter (DM) studies in generic extensions
of the standard model with a R-parity like discrete symmetry that guarantees
the stability of the lightest odd particle. The code computes the DM relic
density, the elastic scattering cross sections of DM on nuclei relevant for
direct detection, and the spectra of positrons, anti-protons and photons
originating from DM annihilation including porpagation of charged cosmic rays.
The cross sections and decay properties of new particles relevant for collider
studies are included as well as constraints from the flavour sector on the
parameter space of supersymmetric models.Comment: 10 pages, Proceedings of LC09, e+e- Physics at the TeV scale and the
Dark Matter connection, Perugia, Italy, 21-24 sept. 200
micrOMEGAs: recent developments
The program micrOMEGAs that calculates the relic density of the lightest
supersymmetric particle (LSP) in the MSSM is presented. The impact of
coannihilation channels and of higher order corrections to Higgs widths is
stressed. The dependence on the RGE code used to calculate the soft parameters
is also discussed.Comment: 5 pages, 2 figures, Talk presented at IDM2002, York, England;
Reference adde
Relic density of dark matter in mSUGRA and non-universal SUGRA
The measurements of WMAP on the relic density of dark matter strongly
constrain supersymmetric models. In mSUGRA where the neutralino LSP is mostly a
bino only rather fine-tuned models survive. On the other hand the relic density
upper limit can be easily satisfied in models with a Higgsino or wino LSP.Comment: 8 pages, 3 figures, Invited talk at Physics at LHC, Vienna, July 200
Dark matter direct detection rate in a generic model with micrOMEGAs2.2
We present a new module of the micrOMEGAs package for the calculation of
WIMP-nuclei elastic scattering cross sections relevant for the direct detection
of dark matter through its interaction with nuclei in a large detector. With
this new module, the computation of the direct detection rate is performed
automatically for a generic model of new physics which contains a WIMP
candidate. This model needs to be implemented within micrOMEGAs2.1.Comment: 38 pages, 3 figures. Change in version number, minor changes in the
text, tables updated, note and appendix adde
Relic density of dark matter in the NMSSM
We present a code to compute the relic density of dark matter in the
Next-to-Minimal Supersymmetric Standard Model (NMSSM). Dominant corrections to
the Higgs masses are calculated with NMHDECAY as well as theoretical and
collider constraints. All neutralino annihilation and coannihilation processes
are then computed with an extended version of micrOMEGAs, taking into acount
higher order corrections to Higgs vertices. We explore the parameter space of
the NMSSM and consider in particular the case of a bino LSP, of a mixed
bino-higgsino LSP and of a singlino LSP. As compared to the MSSM, neutralino
annihilation is often more efficient as it can take place via (additional)
Higgs resonances as well as annihilation into light Higgs states. Models with a
large singlino component can be compatible with WMAP constraints.Comment: 25 pages, 8 figures; one reference added and minor change in
acknowledgement
Relic density of neutralino dark matter in the MSSM with CP violation
We calculate the relic density of dark matter in the MSSM with CP violation.
We analyse various scenarios of neutralino annihilation: the cases of a bino,
bino-wino and bino-Higgsino LSP, annihilation through Higgs, as well as
sfermion coannihilation scenarios. Large phase effects are found, on the one
hand due to shifts in the masses, on the other hand due to modifications of the
couplings. Taking special care to disentangle the effects in masses and
couplings, we demonstrate that the presence of CP phases can have a significant
influence on the neutralino relic abundance. Typical variations in \Omega h^2
solely from modifications in the couplings are O(10%-100%), but can reach an
order of magnitude in some cases.Comment: 36 pages, 21 figures (low resolution). A version with high-resolution
figures can be downloaded from http://cern.ch/kraml/papers/omc
Long-lived Charginos in the Focus-point Region of the MSSM Parameter Space
We analyse the possibility to get light long-lived charginos within the
framework of the MSSM with gravity mediated SUSY breaking. We find out that
this possibility can be realized in the so-called focus-point region of
parameter space. The mass degeneracy of higgsino-like chargino and two
higgsino-like neutralinos is the necessary condition for a long lifetime. It
requires the fine-tuning of parameters, but being a single additional
constraint in the whole parameter space it can be fulfilled in the Constrained
MSSM along the border line where radiative electroweak symmetry breaking fails.
In a narrow band close to the border line the charginos are long-lived
particles. The cross-sections of their production and co-production at the LHC
via electroweak interaction reach a few tenth of pb.Comment: LaTeX, 11 pages, 11 eps figure
A comparison between the detection of gamma rays and positrons from neutralino annihilation
We study the indirect detection of neutralino dark matter using positrons and
gamma rays from its annihilation in the galactic halo. Considering the HESS
data as the spectrum constituting the gamma--ray background, we compare the
prospects for the experiments GLAST and PAMELA in a general supergravity
framework with non--universal scalar and gaugino masses. We show that with a
boost factor of about 10, PAMELA will be competitive with GLAST for typical NFW
cuspy profiles.Comment: 18 pages, 6 figures, 1 reference added. Final version to appear in
JCA