Thesis

Development of high-performance timing detectors for the CMS forward proton spectrometer

• Call:

  IDPASC Portugal - PHD Programme 2014

• Academic Year:

  2014 /2015

• Domain:

  Experimental Particle Physics

• Supervisor:

  Michele Gallinaro

• Co-Supervisor:

  Joao Varela

• Institution:

  Instituto Superior Técnico

• Host Institution:

  Laboratório de Instrumentação e Física Experimental de Partículas

• Abstract:

  A high precision proton spectrometer (PPS) is under development by the CMS experiment. It uses a timing detector, the quartz timing counter (QUARTIC), coupled with silicon photomultipliers (SiPM), in order to measure the time of flight (ToF) of the two forward protons produced in the interaction point in the CMS detector. Considering central exclusive production processes (pp→pXp), 10 ps time resolution detector would provide 2.1 mm spatial resolution on the vertex position and improve of a factor of about 25 the background pile up suppression. The subject of the thesis is the development of this detector, with focus on the readout system. In particular, a starting point will be the 64 channels 130 nm Tof photon emission tomography (TOFPET) chip developed by the LIP, intended for SiPM's signals readout and capable of 25 ps resolution. The resolution will be improved, as well as the digital interface will be modified to match the CMS trigger requirements. One important reaction to be studied is gg→WW to measure the quartic gauge coupling WWgg. With 300 fb-1 integrated luminosity, the PPS expected sensitivities for the couplings a0W/Λ2 and aCW/Λ2 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.