F. Boudjema

micrOMEGAs 2.0.7 : a program to calculate the relic density of dark matter in a generic model

micrOMEGAs2.0 is a code which calculates the relic density of a stable massive particle in an arbitrary model. The underlying assumption is that there is a conservation law like R-parity in supersymmetry which guarantees the stability of the lightest odd particle. The new physics model must be incorporated in the notation of CalcHEP, a package for the automatic generation of squared matrix elements. Once this is done, all annihilation and coannihilation channels are included automatically in any model. Cross-sections at v = 0, relevant for indirect detection of dark matter, are also computed automatically. The package includes three sample models: the minimal supersymmetric standard model (MSSM), the MSSM with complex phases and the NMSSM. Extension to other models, including non supersymmetric models, is described.

Full one-loop corrections to the relic density in the MSSM: A few examples

Abstract We show the impact of the electroweak, and in one instance the QCD, one-loop corrections on the relic density of dark matter in the MSSM which is provided by the lightest neutralino. We cover here some of the most important scenarios: annihilation into fermions for a bino-like neutralino, annihilation involving gauge bosons in the case of a mixed neutralino, the neutralino–stau co-annihilation region and annihilation into a bottom quark pair. The corrections can be large and should be taken into account in view of the present and forthcoming increasing precision on the relic density measurements. Our calculations are made possible thanks to a newly developed automatic tool for the calculation at one-loop of any process in the MSSM. We have implemented a complete on-shell gauge invariant renormalisation scheme, with the possibility of switching to other schemes. In particular we will report on the impact of different renormalisation schemes for tan β .

Automatized full one-loop renormalization of the MSSM: The Higgs sector, the issue of tan{beta} and gauge invariance

We give an extensive description of the renormalization of the Higgs sector of the minimal supersymmetric model in sloops. sloops is an automatized code for the computation of one-loop processes in the MSSM. In this paper, the first in a series, we study in detail the nongauge invariance of some definitions of tan{beta}. We rely on a general nonlinear gauge-fixing constraint to make the gauge parameter dependence of different schemes for tan{beta} explicit at one loop. In so doing, we update, within these general gauges, an important Ward-Slavnov-Taylor identity on the mixing between the pseudoscalar Higgs, A{sup 0}, and Z{sup 0}. We then compare the tan{beta} scheme dependence of a few observables. We find that the best tan{beta} scheme is the one based on the decay A{sup 0}{yields}{tau}{sup +}{tau}{sup -} because of its gauge invariance, because it is unambiguously defined from a physical observable, and because it is numerically stable. The oft used DR scheme performs almost as well on the last count, but is usually defined from nongauge-invariant quantities in the Higgs sector. The use of the heavier scalar Higgs mass in lieu of tan{beta}, though related to a physical parameter, induces radiative corrections that are too large inmorexa0» many instances, and is therefore not recommended.«xa0less

Automatized full one-loop renormalization of the MSSM. II. The chargino-neutralino sector, the sfermion sector, and some applications

An on-shell renormalization program for the chargino/neutralino and the sfermion sectors within the minimal supersymmetric standard model as implemented in a fully automated code, sloops, for the calculation of one-loop processes at the colliders and in astrophysics, is presented. This is a sequel to our previous study where an on-shell renormalization of the Higgs (and the gauge/fermion) sector is performed. The issue of mixing is treated in a unified and coherent manner in all these sectors, in particular, we give some new insight into the renormalization of the mixing angle in the sfermion sector. Like with the issue of

Full O(α) electroweak corrections to double Higgs-strahlung at the linear collider

mathrm{tan}ufeffensuremath{beta}

Full one-loop electroweak radiative corrections to single Higgs production in e + e − .

in the Higgs sector, we discuss different schemes for the mixing in the sfermion sector. We also perform numerical comparisons between our code sloops and different results found in the literature. In particular, we consider loop corrections to the neutralino and sfermion masses, chargino pair production and stau pair production in

Relic density of neutralino dark matter in the MSSM with CP violation

{e}^{+}{e}^{ensuremath{-}}

Full O(α) electroweak and O(αs) corrections to e+e−→tt̄H

colliders as well as a few decays of the heavier chargino. For all these observables, we analyze the

micrOMEGAs : a code for the calculation of Dark Matter properties in generic models of particle interaction

mathrm{tan}ufeffensuremath{beta}

Beyond the MSSM Higgs bosons at 125 GeV

scheme dependence using different definitions of this parameter and comment on the impact of using different renormalization of the mixing parameter in the sfermion sector.