Still more phenomenology

Internet connectivity is worse than ever, so Jan Plefka and I had to resort to an internet cafe for lunch to get online. So I will just give a breif report of what happened since my last report.

First there was Gordon Kane who urged everybody to think about how to extract physical data from the numbers that are going to come out of LHC. He claimed, that one should not expect (easily obtained) useful numbers on susy except the fact that it exists. Especially, it will be nearly impossible to deduce lagrangian parameters (masses etc) for the susy particles as there are not enough independent observables at LHC to completely determine those.

Still, he points out that it will be important to be trained to understand the message that our experimental friends tell us. To this end, there will be the LHC Olympics where Monte Carlo data of the type as it will come out of the experiment will be provided with some interesting physics beyond the standard model hidden and there will be a competition to figure out what's going on.

Today, Dvali was the first speaker. He presented his model that amounts to an IR modification of gravity (of mass term type) that is just beyond current observational limits from solar system observations that would allow for fit of cosmological data without dark energy. One realization of that modification would be a 5D brane world scenario with a 5D Einstein Hilbert action and a 4D EH action for the pull-back of the metric.

Finally, there was Paul Langacker who explained why it is hard to get seasaw type neutrinos from heterotic Z_3 orbifolds. As everybody knows, in the usual scenario neutrino masses arise from physics around some high energy (GUT, Planck?) scale. Therefore neutrino physics might be the most direct source of ultra high energy physics information and one should seriously try to obtain it from string constructions. According to Langacker, this has so far not been possible (intersectin g brane worlds typically preserve lepton number and are thus incompatible with Majorana masses and he showed that none of the models in the class he studied had a usable neutrino sector).