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@PHDTHESIS{Filatov:580449,
      author       = {Filatov, Oleg},
      othercontributors = {Raspiareza, Alexei and Gallo-Voss, Elisabetta},
      title        = {{T}au identification algorithms and study of the {CP}
                      structure of the {Y}ukawa coupling between the {H}iggs boson
                      and tau leptons in {CMS}},
      school       = {Universität Hamburg},
      type         = {Dissertation},
      address      = {Hamburg},
      publisher    = {Verlag Deutsches Elektronen-Synchrotron DESY},
      reportid     = {PUBDB-2023-01292, DESY-THESIS-2023-005},
      series       = {DESY-THESIS},
      pages        = {191},
      year         = {2023},
      note         = {Dissertation, Universität Hamburg, 2023},
      abstract     = {The measurement of the CP properties of the Yukawa coupling
                      of the Higgs boson to τleptons is presented. The data set
                      used for the analysis is collected by the CMS experiment
                      atthe LHC during the Run 2 data-taking period in
                      proton-proton collisions at √s = 13 TeV andcorresponds to
                      an integrated luminosity of 137 fb$^{−1}$. The Yukawa
                      coupling between the Higgsboson and $τ$ leptons is
                      parametrised in terms of the effective mixing angle
                      α$^{Hττ}$, where the valueα$^{Hττ}$ = 0◦(90◦)
                      corresponds to the SM scenario of the pure CP-even (CP-odd)
                      H$ττ$ coupling.The angle between the decay planes of the
                      $τ$ leptons is used as the observable encoding the CP
                      nature of the Higgs boson. The measurement is performed in
                      the $τ$$_e$$τ$$_h$ channel where oneτ lepton decays into
                      an electron and the other hadronically. The results are
                      combined with themeasurement in the $τ$$_q$$τ$$_h$ and
                      $τ$$_h$$τ$$_h$ channels. The observed (expected) value of
                      the effectivemixing angle for the combination is measured to
                      be: α$^{Hττ}$ = −1 ± 19◦(0 ± 21◦) @68.3\% CL.The
                      results are compatible with the SM expectation and the pure
                      CP-odd hypothesis isrejected at the observed (expected)
                      significance level of 3.0 (2.6) standard deviations.The
                      improvements to the $τ$ lepton identification in CMS in the
                      context of the Run 3 preparationare described. Retraining
                      and optimisation of the DeepTau algorithm with the addition
                      ofthe adversarial fine-tuning procedure are performed. The
                      resulting model improves upon theprevious DeepTau model in
                      terms of the background rejection by 10-50\% and has a
                      betterdescription of data with simulation in the H →
                      $ττ$ selection region.A new algorithm called Tau
                      Transformer (TaT) is proposed to overcome the limitations of
                      theDeepTau architecture. The TaT core is based on
                      self-attention layers and features the embeddingmodule
                      allowing for the multimodality treatment of the input
                      representation. Comparison of theTaT model with the
                      retrained DeepTau model and a comparable ParticleNet-based
                      architectureshows consistently improved performance by up to
                      50\% in the misidentification rate across the $p\tiny{T}$,
                      $η$, and decay mode ranges of interest.},
      cin          = {CMS},
      cid          = {I:(DE-H253)CMS-20120731},
      pnm          = {611 - Fundamental Particles and Forces (POF4-611) / PHGS,
                      VH-GS-500 - PIER Helmholtz Graduate School
                      $(2015_IFV-VH-GS-500)$},
      pid          = {G:(DE-HGF)POF4-611 / $G:(DE-HGF)2015_IFV-VH-GS-500$},
      experiment   = {EXP:(DE-H253)LHC-Exp-CMS-20150101},
      typ          = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
      doi          = {10.3204/PUBDB-2023-01292},
      url          = {https://bib-pubdb1.desy.de/record/580449},
}