Stathis Megas: a summer at the front of HEP research

I am a physics student at the university of Athens specialising in High Energy Particle Physics. Studying mathematics and physics, in addition to what is needed to carry on my projects (either here at CERN or back at UoA), is a big part of my day.

However, I also enjoy reading about philosophy, economics and politics. I have been particularly influenced by Tractatus logico-philosophicus, the mentality of patient-centered deontologism and the school of thought of neoclassical economics. Besides reading, I also like playing tennis and fencing. As to whether CERN was everything I expected, I have to say that the linguistic practice surrounding CERN is very flattering. Everyone refers to CERN with the outermost respect and admiration. However, it is only natural to be skeptical before seen it with one’s eyes, and I was, but I am no more. Here I have met people of unparalleled integrity and quality of character, who are smart, as they are kind. It seems that the rumours were right this time, and by living at CERN you truly get a glimpse of what future societies would be like, if we are to adopt the utopian scenarios.

CERN is at the forefront of HEP research. Thus, it is the ideally place to gain experience on experimental testing of theories. The task of my project is to plot the expected and the observed rejection line for the single lepton analysis of CMS (the Delta phi analysis) on the m0-m1/2 plain of a Monte Carlo for cMSSM that I had already produced before coming to CERN. This Monte Carlo is the higgs-aware cMSSM scan at 8TeV and it consists of two different scenarios for the tan(beta) variable and about 600 points on the m0-m1/2 plain for each scenario. In effect this Monte Carlo tells us what we will observe in the case of 1200 different models of the same theory (cMSSM), and by running statistical algorithms (for each model) to determine the compatibility of the SM background with simulated signal of SUSY (which differs among the points of the aforementioned scan), for the case of the rejected line, and the compatibility of the SM background with the actual data, for the observed line, we are able to check for deviations between those two lines. The most interesting thing would be for the expected line to exclude more models (that is points) than the observed line, since that would mean that those points have a significantly big signal and yet they were not rejected by the experiment. Of course, this analysis has already been published concluding that no incompatibility was found for SMS. So, we expect that the observed and the expect line would be compatible up to 1 sigma.