The proposed research programme focuses on several measurements using the top quark using data collected by the ATLAS experiment at the Large Hadron Collider (LHC).

The top quark is the most massive fundamental particles and provides the key to a better understanding of the universe. For example, the large top mass determines, together with the mass of the Higgs boson, the stability of the universe. The mass of the top is the limiting factor in knowing the fate of the universe; this fellowship will measure the top mass with a precision of few hundred MeV, significantly better than currently achieved and will provide the answer to this open question. The kinematic properties of top quarks need to be better measured because top quark pairs are the main background to many other high-profile measurements.

The first objective of the fellowship will address this problem by performing the first measurement of triple differential cross-sections of top quark pairs. These cross-section measurements will be significantly more precise and will be used to constrain a new generation of Monte Carlo samples that will be produced for the next data taking period of LHC (Run3). I will use the same techniques developed for the triple differential measurement to measure the pole-mass of the top quark and to extract PDF in a new region of phase space. Both measurements have a high impact as they can be used by theorist in many predictions and tools. Finally, I will measure a rare process called four tops which can be used to strongly constraint the Standard Model of particle physics.

To carry out this research programme, many simulated Monte Carlo events are required. This can only be achieved using a reliable fast simulation tool. For this reason, the fellowship will aim at developing such tools using a cutting-edge tool called Generative Adversarial Network. The development of this new fast simulation will have far-reaching impact for the whole ATLAS collaboration physics programme.

Michele  Faucci Giannelli - INFN ROMA2