Espriu, D. (Domènec)Hormigos Feliu, Clara2020-01-072020-01-072017-06https://hdl.handle.net/2445/147158Màster Oficial d'Astrofísica, Física de Partícules i Cosmologia, Facultat de Física, Universitat de Barcelona, Curs: 2016-2017, Tutors: Domènec Espriu Climent, Federico MesciaDiscrepancies with the Standard Model (SM) have recently been observed in b s transitions, which hint at a possible description in terms of four-fermion operators. In this work, we seek to describe the anomaly by introducing new heavy fermions. Firstly we build four-fermion operators out of SM and new fermions and introduce the hypothesis of Minimal Flavor Violation. Next we integrate out the heavy degrees of freedom to form operators of four SM fields and obtain an effective coupling constant.27 p.application/pdfengcc-by-nc-nd (c) Hormigos, 2017http://creativecommons.org/licenses/by-nc-nd/3.0/es/FermionsModel estàndard (Física nuclear)Treballs de fi de màsterFermionsStandard model (Nuclear physics)Master's thesesinfo:eu-repo/semantics/masterThesisinfo:eu-repo/semantics/openAccess