@article{MoraisPasechnikPorod2021, author = {Morais, Ant{\´o}nio P. and Pasechnik, Roman and Porod, Werner}, title = {Grand Unified origin of gauge interactions and families replication in the Standard Model}, series = {Universe}, volume = {7}, journal = {Universe}, number = {12}, issn = {2218-1997}, doi = {10.3390/universe7120461}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-250237}, year = {2021}, abstract = {The tremendous phenomenological success of the Standard Model (SM) suggests that its flavor structure and gauge interactions may not be arbitrary but should have a fundamental first-principle explanation. In this work, we explore how the basic distinctive properties of the SM dynamically emerge from a unified New Physics framework tying together both flavor physics and Grand Unified Theory (GUT) concepts. This framework is suggested by a novel anomaly-free supersymmetric chiral E\(_6\)×SU(2)\(_F\)×U(1)\(_F\) GUT containing the SM. Among the most appealing emergent properties of this theory is the Higgs-matter unification with a highly-constrained massless chiral sector featuring two universal Yukawa couplings close to the GUT scale. At the electroweak scale, the minimal SM-like effective field theory limit of this GUT represents a specific flavored three-Higgs doublet model consistent with the observed large hierarchies in the quark mass spectra and mixing already at tree level.}, language = {en} } @phdthesis{Liebler2011, author = {Liebler, Stefan}, title = {LHC phenomenology and higher order electroweak corrections in supersymmetric models with and without R-parity}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-69367}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2011}, abstract = {During the last decades the standard model of particle physics has evolved to one of the most precise theories in physics, describing the properties and interactions of fundamental particles in various experiments with a high accuracy. However it lacks on some shortcomings from experimental as well as from theoretical point of view: There is no approved mechanism for the generation of masses of the fundamental particles, in particular also not for the light, but massive neutrinos. In addition the standard model does not provide an explanation for the observance of dark matter in the universe. Moreover the gauge couplings of the three forces in the standard model do not unify, implying that a fundamental theory combining all forces can not be formulated. Within this thesis we address supersymmetric models as answers to these various questions, but instead of focusing on the most simple supersymmetrization of the standard model, we consider basic extensions, namely the next-to-minimal supersymmetric standard model (NMSSM), which contains an additional singlet field, and R-parity violating models. R-parity is a discrete symmetry introduced to guarantee the stability of the proton. Using lepton number violating terms in the context of bilinear R-parity violation and the munuSSM we are able to explain neutrino physics intrinsically supersymmetric, since those terms induce a mixing between the neutralinos and the neutrinos. Since 2009 the Large Hadron Collider (LHC) at CERN explores the new energy regime of Tera-electronvolt, allowing the production of potentially existing heavy particles by the collision of protons. Thus the near future might provide answers to the open questions of mass generation in the standard model and show hints towards physics beyond the standard model. Therefore this thesis works out the phenomenology of the supersymmetric models under consideration and tries to point out differences to the well-known features of the simplest supersymmetric realization of the standard model. In case of the R-parity violating models the decays of the light neutralinos can result in displaced vertices. In combination with a light singlet state these displaced vertices might offer a rich phenomenology like non-standard Higgs decays into a pair of singlinos decaying with displaced vertices. Within this thesis we present some calculations at next order of perturbation theory, since one-loop corrections provide possibly large contributions to the tree-level masses and decay widths. We are using an on-shell renormalization scheme to calculate the masses of neutralinos and charginos including the neutrinos and leptons in case of the R-parity violating models at one-loop level. The discussion shows the similarities and differences to existing calculations in another renormalization scheme, namely the DRbar scheme. Moreover we consider two-body decays of the form chi_j^0 -> chi_l^\pm W^\mp involving a heavy gauge boson in the final state at one-loop level. Corrections are found to be large in case of small or vanishing tree-level decay widths and also for the R-parity violating decay of the lightest neutralino chi_1^0 -> l^\pm W^\mp. An interesting feature of the models based on bilinear R-parity violation is the correlation between the branching ratios of the lightest neutralino decays and the neutrino mixing angles. We discuss these relations at tree-level and for two-body decays chi_1^0 -> l^\pm W^\mp also at one-loop level, since only the full one-loop corrections result in the tree-level expected behavior. The appendix describes the two programs MaCoR and CNNDecays being developed for the analysis carried out in this thesis. MaCoR allows for the calculation of mass matrices and couplings in the models under consideration and CNNDecays is used for the one-loop calculations of neutralino and chargino mass matrices and the two-body decay widths.}, subject = {Supersymmetrie}, language = {en} } @article{HirschKraussOpferkuchetal.2016, author = {Hirsch, Martin and Krauss, Manuel E. and Opferkuch, Toby and Porod, Werner and Staub, Florian}, title = {A constrained supersymmetric left-right model}, series = {JOURNAL OF HIGH ENERGY PHYSICS}, volume = {03}, journal = {JOURNAL OF HIGH ENERGY PHYSICS}, number = {009}, doi = {10.1007/JHEP03(2016)009}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-168016}, year = {2016}, abstract = {We present a supersymmetric left-right model which predicts gauge coupling unification close to the string scale and extra vector bosons at the TeV scale. The subtleties in constructing a model which is in agreement with the measured quark masses and mixing for such a low left-right breaking scale are discussed. It is shown that in the constrained version of this model radiative breaking of the gauge symmetries is possible and a SM-like Higgs is obtained. Additional CP-even scalars of a similar mass or even much lighter are possible. The expected mass hierarchies for the supersymmetric states differ clearly from those of the constrained MSSM. In particular, the lightest down-type squark, which is a mixture of the sbottom and extra vector-like states, is always lighter than the stop. We also comment on the model's capability to explain current anomalies observed at the LHC.}, language = {en} } @phdthesis{Csallner2006, author = {Csallner, Sigrun}, title = {Produktion und Nachweis schwerer Selektronen}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-22433}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2006}, abstract = {Wir studieren die Produktion und den Nachweis von Selektronen mit Massen jenseits der Schwelle zur Paarerzeugung an k{\"u}nftigen Linearbeschleunigern mit Schwerpunktsenergien von 500 GeV und 800 GeV. Hierzu betrachten wir die Produktion von linken und rechten Selektronen in Assoziation mit dem jeweils leichtesten Neutralino oder Chargino durch Elektron-Elektron-, Elektron-Positron- und Elektron-Photon-Streuung im Rahmen des MSSM. Die Produktion durch Elektron-Elektron-Streuung untersuchen wir zus{\"a}tzlich in zwei erweiterten Modellen, dem NMSSM und einem E6-Modell mit einem zus{\"a}tzlichen U(1)-Eichfaktor.}, subject = {Linearbeschleuniger}, language = {de} } @article{OPUS4-12785, title = {Search for anomaly-mediated supersymmetry breaking with the ATLAS detector based on a disappearing-track signature in pp collisions at √s=7 TeV}, series = {The European Physical Journal C}, volume = {72}, journal = {The European Physical Journal C}, number = {1993}, organization = {ATLAS Collaboration}, doi = {10.1140/epjc/s10052-012-1993-2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-127850}, year = {2012}, abstract = {In models of anomaly-mediated supersymmetry breaking (AMSB), the lightest chargino is predicted to have a lifetime long enough to be detected in collider experiments. This letter explores AMSB scenarios in pp collisions at √s=7 TeV by attempting to identify decaying charginos which result in tracks that appear to have few associated hits in the outer region of the tracking system. The search was based on data corresponding to an integrated luminosity of 1.02 fb\(^{-1}\) collected with the ATLAS detector in 2011. The p\(_T\) spectrum of candidate tracks is found to be consistent with the expectation from Standard Model background processes and constraints on the lifetime and the production cross section were obtained. In the minimal AMSB framework with m\(_{3/2}\)<32 TeV, m\(_0\)<1.5 TeV, tanβ=5 and μ>0, a chargino having mass below 92 GeV and a lifetime between 0.5 ns and 2 ns is excluded at 95 \% confidence level.}, language = {en} } @article{OPUS4-15018, title = {Search for supersymmetry in events containing a same-flavour opposite-sign dilepton pair, jets, and large missing transverse momentum in \(\sqrt {s}\) = 8 TeV pp collisions with the ATLAS detector}, series = {European Physical Journal C: Particles and Fields}, volume = {75}, journal = {European Physical Journal C: Particles and Fields}, number = {7}, organization = {ATLAS Collaboration}, doi = {10.1140/epjc/s10052-015-3518-2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-150184}, pages = {318}, year = {2015}, abstract = {Two searches for supersymmetric particles in final states containing a same-flavour opposite-sign lepton pair, jets and large missing transverse momentum are presented. The proton-proton collision data used in these searches were collected at a centre-of-mass energy \(\sqrt {s}\) = 8 TeV by the ATLAS detector at the Large Hadron Collider and corresponds to an integrated luminosity of 20.3 fb\(^{-1}\). Two leptonic production mechanisms are considered: decays of squarks and gluinos with Z bosons in the final state, resulting in a peak in the dilepton invariant mass distribution around the Z-boson mass; and decays of neutralinos (e.g. \(\tilde{χ}\)\(^{0}_{2}\) → ℓ\(^{+}\)ℓ\(^{-}\)\(\tilde{χ}\)\(^{0}_{1}\)), resulting in a kinematic endpoint in the dilepton invariant mass distribution. For the former, an excess of events above the expected Standard Model background is observed, with a significance of three standard deviations. In the latter case, the data are well-described by the expected Standard Model background. The results from each channel are interpreted in the context of several supersymmetric models involving the production of squarks and gluinos.}, language = {en} }