TY  - THES
AB  - The Standard Model of particle physics has proved itself as a reliable theory to describe interactions of elementary particles. However, many questions concerning the Higgs sector and the associated electroweak symmetry breaking are still open, even after (or because) a light Higgs boson has been discovered. The 2 → 2 scattering amplitude of weak vector bosons is suppressed in the Standard Model due to the Higgs boson exchange. Therefore, weak vector boson scattering processes are very sensitive to additional contributions beyond the Standard Model. Possible new physics deviations can be studied model-independently by higher dimensional operators within the effective field theory framework. In this thesis, a complete set of dimension six and eight operators are discussed for vector boson scattering processes. Assuming a scenario where new physics in the Higgs/Goldstone boson decouples from the fermion-sector and the gauge-sector in the high energy limit, the impact of the dimension six operator $LL_{HD}$ and dimension eight operators L_S0 and L_S1 to vector boson scattering processes can be studied separately for complete processes at particle colliders. However, a conventional effective field theory analysis will violate the S-matrix unitarity above a certain energy limit. The direct T-matrix scheme is developed to allow a study of effective field theory operators consistent with basic quantum-mechanical principles in the complete energy reach of current and future colliders. Additionally, this scheme can be used preventively for any model, because it leaves theoretical predictions invariant, which already satisfies unitarity. The effective field theory approach is further extended by allowing additional generic resonances coupling to the Higgs/Goldstone boson sector, namely the isoscalar-scalar, isoscalar-tensor, isotensor-scalar and isotensor-tensor. In particular, the Stückelberg formalism is used to investigate the impact of the tensor degree of freedoms, separately. The necessity of these additional resonance, especially for weakly coupled resonances, are manifest by comparing vector boson scattering distributions of the resonance model and of the corresponding effective field theory operators, where the resonance is integrated out. For different parameter sets, the distributions of vector boson scattering processes for the large hadron collider at center of mass energy of sqrt{s}= 14 TeV are calculated with the Monte-Carlo generator WHIZARD. As part of this thesis, the resonance model and the effective field operators including the T-matrix unitarization scheme are implemented in WHIZARD. With the WHIZARD models SSC_2, SSC_AltT and SM_ul, a tool-set is provided to study new physic in the Goldstone boson/Higgs sector within complete experimental analysis at the large hadron collider or other future colliders.
AU  - Sekulla, Marco
DA  - 2015
KW  - Unitarität
KW  - elektroschwache Physik
KW  - neue Physik
KW  - Effektive Theorie
KW  - Event-generator
KW  - electroweak physics
KW  - Higgs
KW  - new Physics
LA  - eng
PY  - 2015
TI  - Anomalous couplings, resonances and unitarity in vector boson scattering
UR  - https://nbn-resolving.org/urn:nbn:de:hbz:467-9793
Y2  - 2024-11-22T01:57:04
ER  -