A study of W W scattering at the LHC

This thesis presents a study of scattering at the LHC, a proton-proton collider being built at CERN and due to start its first run in 2007. The case where no new particles are discovered before the start of the LHC is analysed. The elastic scattering of is considered and the semileptonic 1 decay channels of the bosons are investigated. Signals and backgrounds are simulated using Atlfast, a fast simulation programme for the ATLAS experiment. This specific channel causes violation of unitarity at 1.2 TeV. Therefore, unitarisation is performed and this leads to different resonance scenarios, five of which are investigated. The final signal to background ratio after applying various kinematic cuts on events is greater than one for all the five scenarios. A comparison between the algorithm and cone algorithm is also performed to find out which jet-finding analysis yields a better signal to background ratio. The algorithm proves very efficient in reducing the background by an approximate factor of 1.5 better than the cone algorithm for various scenarios. A preliminary study is done to find the effects of both the cone radius of the cone algorithm and the R-parameter of the analysis on the width of the hadronic mass spectrum. A value of 0.7 for the cone radius is found to be the optimum, while the corresponding R-parameter of 1.0 is used. The analysis shows that ATLAS will be able to observe scalar and vector resonances of up to 1.4 TeV after a year of high luminosity run of 100 fb at the LHC.