Study of the Loss of Information from the Modified Mass-Drop Tagger in PYTHIA 8 for Z to qqbar

Sammanfattning: In this thesis, the information loss from the modified Mass-Drop tagging of a Z to qqbar jet is studied for a pp collision at LHC centre-of-mass energies in PYTHIA 8 using FastJet 3. The jet created by the Z has minimum transverse momentum of 200 GeV. This is then searched for subjets via two methods: a Cambridge/Aachen algorithm and a modified Mass-Drop Tagger with different z-cut values. The subjets located through these two methods are compared and specific regions of the jets are examined further. The transverse momenta used as a measurement of information, and the amount of transverse momentum removed by the modified Mass-Drop Tagger in the different regions is used to measure the information loss. There is a sign of information loss by the modified Mass-Drop Tagger, in that it removes more transverse momentum than only the background. Indications of the removal of particles that are caused by the Z decay are found and further ways of investigating this removal are proposed.