Dark Matter Workshop

The Dark Matter Workshop at SINP, Kolkata is going good so far. Today is the fourth day of the workshop and most of the areas related to dark matter theory, phenomenology and experiments have been covered so far by various invited speakers. There were talks related to model building using SUSY, GUT, Extra U(1) as well some string theory inspired models by speakers like Mambrini, Ibarra, Covi, X. Tata and many others. At the same time there were talks on experiments like DAMA (by F. Capella) , PAMELA, Fermi-LAT and other experiments as well as the possible collider signatures. It was indeed good to listen to talks covering such a wide varieties but of course crucial as far as dark matter is concerned. It seemed somehow to me that people are taking direct detection experiments and possible LHC signatures of Dark matter more seriously than indirect detection experiments like PAMELA, Fermi-LAT etc. It might be because of the existing astrophysical explanations of various cosmic ray anomalies. But as Ibarra pointed out, the Gamma ray line in the sky should be taken more seriously compared to positron excess, since it has got no astrophysical explanations. There was an interesting model where people put a chern-simons term mixing the photon with a hidden gauge boson. In that case dark matter annihilation(for relic density) and dark matter going to gamma rays involve the same vertex (rather than loop suppressed in case of neutralinos in MSSM) and hence can give rise to a TeV gamma ray line observed. Anyway it seems constraints from CDMS, XENON, signal from DAMA, Gamma ray line observed by Fermi and future collider signatures are going to play the key role in the business of dark matter!