Search for new physics with fat jets at LHCb

The search for new physics at the LHCb includes the study and reconstruction of fat $b \overline{b}$-jets. These fat jets have a large radius and a rich substructure, and taking a closer look at the internal structure of the jet may help us uncover new physics. In fact, with fat jet techniques, it is possible to search for low mass particles decaying in boosted $b \overline{b}$ quarks. This study apply the jet substructure technique called SoftDrop, to groom and clean up the jets to remove background and underlying events. After applying SoftDrop, its effect on the jet is studied through two analysis. First the mass distribution of the jet after applying SoftDrop is compared to the original jet, and secondly the N-subjettiness is calculated to investigate how likely it is that the jet consists of multiple subjets. In the analysis we discover that the effect of SoftDrop heavily depends on the fat jet radius and on the tuning of the SoftDrop parameters.