Search for anomalous gauge couplings and new resonances in photon fusion processes at LHC
IDPASC Portugal - PHD Programme 2017
2017 / 2018
Experimental Particle Physics
Instituto Superior Técnico
Laboratório de Instrumentação e Física Experimental de Partículas
A high Precision Proton Spectrometer (PPS) was recently installed in the CMS experiment in order to measure protons produced in very forward direction in pp collision at LHC. The detection and measurement of two forward protons will allow the study of photon fusion processes by using the LHC as a photon collider. LIP has a strong involvement and coordination responsibilities in the PPS detector. The thesis will involve the study of the detector performance and the analysis of data. One important reaction to study is exclusive production of diphoton events with scattered protons detected in the PPS searching for new resonances. Another important reaction to be studied is photon+photon?WW to measure the quartic gauge coupling WW??. With 300 fb-1 integrated luminosity, the PPS expected sensitivities for the couplings a0W/?2 and aCW/?2 are of the order of 1 and 3x10-6 GeV-2 respectively (95% CL). These values are two orders of magnitude better than what is expected with the central detectors only for the same luminosity and 10^(3-4) times better than LEP and Tevatron. A number of other physics studies will be possible aiming at an understanding of the QCD mechanisms involved in exclusive central production.