On March 23, the LHCb collaboration announced a first evidence for non-universal behaviour of interactions felt by electrons and muons. If confirmed, this phenomena may play an important role to solve what is called the flavour puzzle in particle physics: "Why do we have three generations of fundamental fermions?", "What is the cause of their observed mass spectrum?" and "How did antimatter disappear from the universe?"
The LHCb experiment at the LHC is a facility that performs many measurements to study the flavour puzzle. In this seminar we will examine the results recently obtained in rare semileptonic decays of B-meson; the topic that lead to attention of the press.