Search for Top in TOTEM

The work assigned to me during this summer (from June 19th to August 11th) was in the "Search for Top in TOTEM" project, a CMG project in collaboration with TOTEM, under the supervision of Martijn Mulders and Laurent Forthomme. The goal is to determine physical properties of the top anti top quark pair (tt) created by central exclusive processes, particularly the invariant mass. For that it is necessary to relate the measurements of the reconstructed top pair kinematics in the central detector of CMS with the detected protons in the Roman Pots of TOTEM just outside the interaction site, about 200 m from it. CMS only considers decay products from the proton collision, it does not regard the forward protons that participated in the collision. On the contrary, TOTEM does consider these protons. In this research measurements of both TOTEM and CMS were combined Figure 1 shows a diagram of the production of the top anti top pair from the interaction of the two protons. A central exclusive process occurs when the protons involved in the collision do not decay but just recoil and lose momentum. This loss in momentum is represented by ξ the fractional momentum loss. These protons get out of the LHC beam and are detected on the Roman Pots detectors of TOTEM located 100 m apart from the interaction point on the central detector of CMS. There are two Roman Pots in each arm adding up to a total of 4 Pots.