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@PHDTHESIS{Fuchs:224288,
      author       = {Fuchs, Elina},
      title        = {{I}nterference effects in new physics processes at the
                      {LHC}},
      issn         = {1435-8085},
      school       = {Universität Hamburg},
      type         = {Dissertation},
      address      = {Hamburg},
      publisher    = {Verlag Deutsches Elektronen-Synchrotron},
      reportid     = {PUBDB-2015-03479, DESY-THESIS-2015-037},
      series       = {DESY-THESIS},
      pages        = {188},
      year         = {2015},
      note         = {Dissertation, Universität Hamburg, 2015},
      abstract     = {Interference effects between nearly mass-degenerate
                      particles are ad-dressed in this thesis, comprising
                      higher-order calculations, a model-independent method to
                      calculate interference terms efficiently and
                      aphenomenological application to current Higgs searches at
                      the LHC.Predictions of cross sections and decay widths can
                      be severelyaffected by interference terms between
                      quasi-degenerate states arising inmodels beyond the Standard
                      Model. We formulate a generalisation ofthe narrow-width
                      approximation (NWA) which allows for a consistenttreatment
                      of such effects by factorising the interference term into
                      on-shellmatrix elements of the production and decay parts,
                      optionally furtherapproximated as simple interference weight
                      factors, incorporating one-loop and real corrections in a
                      UV- and IR-finite way. We apply thegeneralised NWA to
                      interfering MSSM Higgs bosons in the processχ 04 → χ 01
                      Φ → χ 01 τ + τ − , Φ = h, H and achieve an
                      agreement of betterthan $1\%$ with the unfactorised
                      three-body decay of the neutralino χ 04at NLO. Further, we
                      derive the approximation of the full propagatormatrix of the
                      three neutral MSSM Higgs bosons in terms of Breit-Wigner
                      propagators and on-shell wave-function normalisation
                      factorsˆ This is found to accurately reproduce the full
                      mixing properties alsoZ.in the case of complex MSSM
                      parameters. Moreover, it enables theimplementation of the
                      total width at the highest available order. Usingˆthe
                      Breit-Wigner and Z-factorformalism, we calculate
                      CP-violatinginterference effects of the neutral MSSM Higgs
                      bosons in the processb ̄ b → h 1,2,3 → τ + τ − ,
                      induced by the phase φ A t . We find a very
                      significant,destructive interference between h 2 and h 3 ,
                      particularly for large μ. Asa consequence, a considerable
                      parameter region in the complex M h mod+scenario, which
                      would appear to be ruled out if this interference
                      wereneglected, actually escapes the current exclusion bounds
                      from the LHC.},
      cin          = {T},
      cid          = {I:(DE-H253)T-20120731},
      pnm          = {611 - Fundamental Particles and Forces (POF3-611) / PHGS,
                      VH-GS-500 - PIER Helmholtz Graduate School
                      $(2015_IFV-VH-GS-500)$},
      pid          = {G:(DE-HGF)POF3-611 / $G:(DE-HGF)2015_IFV-VH-GS-500$},
      experiment   = {EXP:(DE-MLZ)NOSPEC-20140101},
      typ          = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
      doi          = {10.3204/DESY-THESIS-2015-037},
      url          = {https://bib-pubdb1.desy.de/record/224288},
}