Relive 2011 in Particle Physics: Part 3

SUSY Was Not Around the Corner (by Philip E. Gibbs): Abstract: ATLAS has produced new exclusions limits for SUSY (Taffard) models using jets plus missing transverse energy from 1/fb of data. These go well beyond previous limits leading to the conclusion that “SUSY” was NOT “just rounnd the corner” as theorists hoped.

Big Day for Higgs Boson (by Philip E. Gibbs): Abstract: Today at the EPS conference in Grenoble the world’s largest hadron colliders will be revealing the results of their latest searches for the Higgs boson, using data collected up until the last few weeks. We will be posting the plots here as they appear. The individual experiments Dzero, CDF, ATLAS and CMS will each show their all channel combined plots. There will also be separated plots for individual channels and some separate searches for a charged Higgs as predicted in some models such as MSSM.

Higgs Combos (by Philip E. Gibbs): Abstract: Some people have been asking if confidence level plots can be combined now that we have the individual data from Dzero, CDF, ATLAS and CMS. The answer is of course not. You need to combine the underlying event data and all the backgrounds etc., and re-derive the levels from that.

Global Fit Kills (or at least Wounds) the Standard Model (by Philip E. Gibbs): Abstract: A few days ago I showed how to combine the Higgs confidence level plots by adding in inverse square. At the time I did not understand why this worked (I am a bit slow at statistics.) Since then I have looked again at the work on electroweak precision tests and the global fit where you can find the same calculation being done. The inverse square of the 95% confidence level limits is just one-quarter of the Δχ2 estimator. For independent variables these can be directly added to give an overall Δχ2 which can then be mapped back to an overall confidence level limit. This is exactly what I was doing in my combinations. So now I know that these combo plots are essentially correct, neglecting any correlations which should be zero.