Master Thesis Open Access
Pfeffer, Emanuel
<?xml version='1.0' encoding='UTF-8'?> <record xmlns="http://www.loc.gov/MARC21/slim"> <leader>00000nam##2200000uu#4500</leader> <datafield tag="100" ind1=" " ind2=" "> <subfield code="a">Pfeffer, Emanuel</subfield> <subfield code="u">KIT/ETP</subfield> </datafield> <datafield tag="542" ind1=" " ind2=" "> <subfield code="l">open</subfield> </datafield> <datafield tag="856" ind1="4" ind2=" "> <subfield code="s">5280328</subfield> <subfield code="u">https://publish.etp.kit.edu/record/22082/files/Masterthesis_Emanuel_Pfeffer.pdf</subfield> <subfield code="z">md5:519f7c9df7dc8f930eda005fd3f1a86a</subfield> </datafield> <datafield tag="041" ind1=" " ind2=" "> <subfield code="a">eng</subfield> </datafield> <datafield tag="980" ind1=" " ind2=" "> <subfield code="a">thesis</subfield> <subfield code="b">master-thesis</subfield> </datafield> <controlfield tag="005">20221202161856.0</controlfield> <datafield tag="520" ind1=" " ind2=" "> <subfield code="a"><p>In this thesis, the interplay of two elementary particles of the SM, the two heaviest quarks top (t) and bottom (b), is studied in detail. Processes in which a top quark-antiquark pair occurs in associated production with two bottom quarks (tt+bb)&nbsp;play an important role in particle physics. The two quarks show a high mass difference and their associated production is therefore particularly difficult to model, accompanied by large uncertainties [6]. In addition, events involving this process constitute a large irreducible background in measurements of tt+H production in H&nbsp;&rarr;&nbsp;bb&nbsp;decays. These measurements are an essential test of the SM and an important constraint of physics beyond the SM. Consequently, the tt+bb&nbsp;process needs to be thoroughly understood.</p> <p>Events comprising tt+bb&nbsp;processes are analyzed at two different Monte Carlo event simulation levels in this thesis.<br> The first part compares different existing event simulations used at the CMS experiment for the tt+bb&nbsp;process in the single-lepton channel and investigates possible differences in the modeling. The analysis is technically realized in a way that allows a direct comparison of the simulations with those of the ATLAS experiment. The comparison of simulations of both experiments is performed building on this analysis. This enables the design of a common strategy between ATLAS and CMS.</p> <p>The second part focuses on strategies for assigning b jets to their origin. Since top quarks decay into b quarks almost exclusively, the final state of an event involving the tt+bb&nbsp;process usually consists of four or more b jets. However, it is unknown in the event reconstruction which b jets result from top quark decays and which originate from additional gluon radiation and subsequent splittings into pairs of b quarks in the event.</p></subfield> </datafield> <datafield tag="260" ind1=" " ind2=" "> <subfield code="c">2021-01-12</subfield> </datafield> <datafield tag="700" ind1=" " ind2=" "> <subfield code="a">Husemann, Ulrich</subfield> <subfield code="u">KIT/ETP</subfield> <subfield code="4">ths</subfield> </datafield> <datafield tag="700" ind1=" " ind2=" "> <subfield code="a">Müller, Thomas</subfield> <subfield code="u">KIT/ETP</subfield> <subfield code="4">ths</subfield> </datafield> <datafield tag="700" ind1=" " ind2=" "> <subfield code="a">Schröder, Matthias</subfield> <subfield code="u">KIT/ETP</subfield> <subfield code="4">ths</subfield> </datafield> <datafield tag="700" ind1=" " ind2=" "> <subfield code="a">van der Linden, Jan</subfield> <subfield code="u">KIT/ETP</subfield> <subfield code="4">ths</subfield> </datafield> <datafield tag="245" ind1=" " ind2=" "> <subfield code="a">Studies on tt+bb production at the CMS experiment</subfield> </datafield> <datafield tag="653" ind1=" " ind2=" "> <subfield code="a">CERN</subfield> </datafield> <datafield tag="653" ind1=" " ind2=" "> <subfield code="a">CMS</subfield> </datafield> <datafield tag="653" ind1=" " ind2=" "> <subfield code="a">Experiment</subfield> </datafield> <datafield tag="653" ind1=" " ind2=" "> <subfield code="a">Monte Carlo Simulation</subfield> </datafield> <datafield tag="653" ind1=" " ind2=" "> <subfield code="a">Machine Learning</subfield> </datafield> <datafield tag="653" ind1=" " ind2=" "> <subfield code="a">Artificial Intelligence</subfield> </datafield> <datafield tag="653" ind1=" " ind2=" "> <subfield code="a">Deep Neural Networks</subfield> </datafield> <datafield tag="653" ind1=" " ind2=" "> <subfield code="a">tt+bb</subfield> </datafield> <datafield tag="653" ind1=" " ind2=" "> <subfield code="a">top</subfield> </datafield> <datafield tag="909" ind1="C" ind2="O"> <subfield code="o">oai:publish.etp.kit.edu:22082</subfield> <subfield code="p">user-cms</subfield> <subfield code="p">user-etp</subfield> </datafield> <datafield tag="980" ind1=" " ind2=" "> <subfield code="a">user-cms</subfield> </datafield> <datafield tag="980" ind1=" " ind2=" "> <subfield code="a">user-etp</subfield> </datafield> <controlfield tag="001">22082</controlfield> </record>