Search for Quantum Black Holes and ADD Extra Dimensions in the opposite sign dimuon channel in proton-proton collisions with the ATLAS detector at √s = 8 TeV

A search for Beyond the Standard Model physics is performed with the ATLAS detector in the opposite sign dimuon channel using the 20 fb−1 of data collected in 2012 at √s = 8 TeV. No excess is found above the Standard Model expectation. Using a Bayesian statistical anal- ysis, model dependent 95% Credibility Level Bayesian exclusion limits are extracted for two models of gravitationally-related beyond the Standard Model phenomena. For the ADD and RS quantum black hole models, limits of 3.32 and 1.95 TeV are set on the extradimensional Planck Scale, and for ADD Large Extra dimensions, limits ranging from 2.8-4.4 TeV are set on the string scale for the GRW, HLZ and Hewett formalisms. In addition, a study is performed to estimate the effect of increasing noise cuts in the ATLAS Level-1 Calorimeter Trigger on the physics efficiency of W → eν and tt ̄ and on the Level-1 missing transverse energy trigger rate. Results suggest that higher noise cuts could reduce the Level-1 missing transverse energy trigger rate with a minimal loss of physics efficiency.