http://arxiv.org/pdf/1305.0456v1.pdf
Non-Baryonic Dark Matter in Cosmology:
May 2013:
Abstract.
This paper is based on lectures given at the ninth Mexican School on Gravitation and Mathematical Physics. The lectures (as the paper) were a broad-band review of the current status of non-baryonic dark matter research. I start with a historical overview of the evidences of dark matter existence, then I discuss how dark matter is distributed from small scale to large scale, and I then verge the attention to dark matter nature: dark matter candidates and their detection. I finally discuss some of the limits of the ΛCDM model, with particular emphasis on the small scale problems of the paradigm.
SUMMARY AND OUTLOOK:
In this paper, I have discussed the many evidences for DM existence, how it is distributed in cosmic structures, its particle nature and the "zoo" of candidates that could be the constituents of the dark Universe. I have discussed the direct and indirect methods of detection, and finally some of the known problems of one of the CDM models that nowadays seem to be the favorite one from observations, namely the ΛCDM model often called "the concordance model" or "standard model of big bang cosmology". Concerning the evidences of DM existence, in the last years, strong evidences come from galaxy clusters collisions, showing through weak lensing that clusters are made of a dissipationless component, not only gas. Cosmic shear, the weak lensing of the LSS is another strong evidence that Universe contains matter which deflect the light of remote objects. In 2012, was observed a weak lensing signature of a filament in the supercluster A222/A223, connecting the two clusters[324] An important news, coming from particle physics is the absence of SUSY effects in LHC experiments, and if this will be confirmed in the next years, one of the most promising candidates of DM, the neutralino, should be substituted by other kind of DM. The great hope put on colliders to reveal hints of the so called "new physics", has been up to this moment betrayed, but in 2015 LHC could give new and unexpected results. Colliders give a different point of view on DM with respect to astrophysical experiments, and at the same time they could provide the needed information to reveal the physics at the base of the DM particles. At the same time, colliders are not able to test its abundance in the universe or its cosmological stability. This is the reason colliders and direct and indirect searches must go hand in hand. Direct and indirect detection of DM has improved a lot in the last years. As early discussed, there was even a claim of axion detection, after disproved, and the DAMA experiment is claiming since a decade to have signal DM, even this never confirmed. The space telescope Fermi, has meanwhile studied the galactic center, MW dSphs, clusters of galaxies, the IGRB, finding possible evidences of DM existence but not any certainty. To disentangle the astrophysical signal from DM annihilation signal is a not easy task. The 511 MeV line observed several years ago by INTEGRAL, differently from other signals, is difficult to explain through astrophysics (SN Ia, Hipernovae, etc.), but MeV DM is difficult to explain. Indirect, experiments have put constraints to DM-nucleon cross-section which seems to be in the 1−10 ' zb range. An important improvement in direct search are the ton scale detectors (e.g., ArDM). These kind of detectors can test the most attractive DM models, including KK DM, that was before out of reach. Apart from the constraints to SUSY from LHC, these detectors could put strong constraints on SUSY and/or TeV scale physics. The next step, would be the detection of WIMPs, and the consequent precise measurements of its mass and interactions.