Ref HAL: in2p3-00024566_v1
Ref Arxiv: astro-ph/0508349
DOI: 10.1103/PhysRevD.74.023518
WoS: 000239512000032
Ref. & Cit.: NASA ADS
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10 Citations
Résumé:

The detection of non-baryonic dark matter through its gamma-ray annihilation in the centre of our galaxy has been studied. The gamma fluxes according to different models have been simulated and compared to those expected to be observed with the Alpha Magnetic Spectrometer (AMS), during a long-term mission on board of the International Space Station. Under the assumption that the dark matter halo is composed of the lightest, stable supersymmetric particle, the neutralino, the results of the simulations in the framework of mSUGRA models, show that with a cuspy dark matter halo or a clumpy halo, the annihilation gamma-ray signal would be detected by AMS. More optimistic perspectives are obtained with the Anomaly Mediated Supersymmetry Breaking (AMSB) model. The latter leads also to a cosmologically important 6Li abundance. Finally, the discovery potential for the massive Kaluza-Klein dark matter candidates has been evaluated and their detection looks feasible.

Commentaires: 15 pages, 7 figures - AMS

Ref HAL: in2p3-00025722_v1
Ref Arxiv: astro-ph/0508141
DOI: 10.1088/1475-7516/2006/07/010
WoS: 000239451000006
Ref. & Cit.: NASA ADS
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46 Citations
Résumé:

Stable particle dark matter may well originate during the decay of long-lived relic particles, as recently extensively examined in the cases of the axino, gravitino, and higher-dimensional Kaluza-Klein (KK) graviton. It is shown that in much of the viable parameter space such dark matter emerges naturally warm/hot or mixed. %due to the kinetic energy imparted %on the dark matter particles during decay. In particular, decay produced gravitinos (KK-gravitons) may only be considered cold for the mass of the decaying particle in the several TeV range, unless the decaying particle and the dark matter particle are almost degenerate. Such dark matter candidates are thus subject to a host of cosmological constraints on warm and mixed dark matter, such as limits from a proper reionisation of the Universe, the Lyman-alpha forest, and the abundance of clusters of galaxies.. It is shown that constraints from an early reionsation epoch, such as indicated by recent observations, may potentially limit such warm/hot components to contribute only a very small fraction to the dark matter.

Commentaires: 6 pages, 3 figures

Ref HAL: hal-00266464_v1
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Résumé:

A review of the activity of the European Network ``Physics at Colliders'' in the area of SUSY particle physics is presented.

Commentaires: Meeting of the European Network "Physics at Colliders", Montpellier (France) Sept-26-27 , 2004.

Ref HAL: in2p3-00121100_v1
Ref Arxiv: hep-ph/0504021
DOI: 10.1016/j.physletb.2006.12.025
WoS: 000244313500021
Ref. & Cit.: NASA ADS
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25 Citations
Résumé:

It is shown that gravitinos with mass m_{3/2} ~ 0.1-1 MeV may provide suitable cold dark matter candidates in scenarios of gauge mediated supersymmetry breaking (GMSB) under SO(10) grand unification coupled to supergravity, which accommodate a messenger sector of mass scale M_X ~ 10^6 GeV. This is due to the combined effects of renormalizable loop-suppressed operators and generic non-renormalizable ones governing the dilution of a pre-existing equilibrium gravitino abundance via messenger decay. The above range of gravitino and messenger masses can be accommodated in indirect GMSB scenarios. The gravitino abundance does not depend on the post-inflationary reheat temperature and it is shown that leptogenesis can generate successfully the baryon asymmetry.

Commentaires: 8 pages - version to appear in Phys.Lett.B ; discussion of one loop annihilation cross-section modified, conclusions unchanged

Ref HAL: in2p3-00025952_v1
Ref Arxiv: hep-ph/0506129
DOI: 10.1103/PhysRevD.73.043514
WoS: 000235669800026
Ref. & Cit.: NASA ADS
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43 Citations
Résumé:

This paper investigates the parameter space of theories with gauge mediated supersymmetry breaking leading to gravitino (cold) dark matter with mass m_{3/2}= 1keV - 10MeV. We pay particular attention to the cosmological role of messenger fields. Cosmology requires that these messengers decay to the visible sector if the lightest messenger mass M_X > 30TeV. We then examine the various possible messenger number violating interactions allowed by the symmetries of the theory and by phenomenology. Late messenger decay generally results in entropy production hence in the dilution of pre-existing gravitinos. We find that in SU(5) grand unification only specific messenger-matter couplings allow to produce the required amount of gravitino dark matter particles. Gravitino dark matter with the correct abundance is however expected in larger gauge groups such as SO(10) for generic non-renormalizable messenger-matter interactions and for arbritrarily high post-inflationary reheating temperatures.

Commentaires: 20 pages, double column revtex format, 5 figures

Ref Arxiv: hep-th/0411198
DOI: 10.1142/S0217751X05022433
WoS: 000233464800004
Ref. & Cit.: NASA ADS
20 Citations
Résumé:

On the basis of recent results extending non-trivially the Poincaré symmetry, we investigate the properties of bosonic multiplets including 2-form gauge fields. Invariant free Lagrangians are explicitly built which involve possibly 3- and 4-form fields. We also study in detail the interplay between this symmetry and a U(1) gauge symmetry, and in particular the implications of the automatic gauge-fixing of the latter associated to a residual gauge invariance, as well as the absence of self-interaction terms.

Ref HAL: hal-00266466_v1
Ref Arxiv: hep-th/0407168
Ref. & Cit.: NASA ADS
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Résumé:

We investigate a non-trivial extension of the $D-$dimensional Poincaré algebra. Matrix representations are obtained. The bosonic multiplets contain antisymmetric tensor fields. It turns out that this symmetry acts in a natural geometric way on these $p-$forms. Some field theoretical aspects of this symmetry are studied and invariant Lagrangians are explicitly given.

Commentaires: LaTeX, 13 pages, contribution to the XI-th International Conference Symmetry Methods in Physics, Prague, June 21-24, 2004, presented by M. Rausch de Traubenberg