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HEPHY Vienna Theory Group

HEPHY Vienna Theory Group. Members. Walter Majerotto Helmut Eberl Wolfgang Lucha Sabine Kraml Christian Weber – fixed term pos. Karol Kova ří k – PhD student Wilhelm Öller – PhD student. Working Fields. Supersymmet r y (SUSY) H. Eberl, K. Kova ří k, S. Kraml,

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HEPHY Vienna Theory Group

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  1. HEPHY Vienna Theory Group

  2. Members • Walter Majerotto • Helmut Eberl • Wolfgang Lucha • Sabine Kraml • Christian Weber – fixed term pos. Karol Kovařík– PhD student Wilhelm Öller– PhD student

  3. Working Fields Supersymmetry (SUSY) H. Eberl, K. Kovařík, S. Kraml, W. Majerotto, W. Öller, C. Weber Bound quark states, Finite quantum field theories W. Lucha

  4. Supersymmetry The way to the Theory of Everything? • Symmetries play a central rôle in modern physics (like in Arts), • as theyreflect the fundamental laws of Nature. SUPERSYMMETRY – or SUSY for short - is a symmetry between matter particles (fermions) and carriers of force (bosons). It offers the possibility of embedding the Standard Model of particles into a larger and a more complete theory. Unification? a

  5. Principle of Symmetry: Symmetry transformations do not change the form of the laws of Nature as illustrated here in this four pictures all representing our beloved Marylin despite the colour and mirror transformations

  6. SUSY particle spectrum. green: known particles of the Standard Model. red: new particles (Higgs bosons and SUSY partners). SUSY - The true love of particle physists? Bosonen Fermionen In a supersymmetric theory, for every particle there exist a partner particle. If SUSY is realized in Nature then for every known SM particle there must be a supersymmetric partner.

  7. SUSY-particles in experiments SUSY particles can have very spectacular signatures due to cascade decays. Here we see a possible squark-gluino production at LHC and the additional cascade decays of them. In the right figure we see a simulation of such a signature in the CMS detector. The search for these new supersymmetric particles is one of the main tasks of the experiments at the Tevatron in the USA, at LHC at CERN, and at a Future Linear Collider. Die Suche nach diesen neuen supersymmetrischen Teilchen ist eine der vorrangigen Aufgaben der großen Experimente am Tevatron in den USA, am LHC, am CERN und am geplanten e+ e- Linear Collider.

  8. radiative corrections Renormalization a possible source CP violation in SUSY Lepton flavour violation Main Topicsof the SUSY Group Loop calculations

  9. Renormalization in the MSSM Goal: Access to higher fundamental “GUT” scale Precision experiments – Born approximation is not sufficient. Inclusion of “loop” contributions necessary! Our contribution: compared to the SM, in the MSSM there are mass matrices (for sfermions, charginos and neutralinos) and related mixing matrices which have to be renormalized. We worked out a consistent concept of renormalization and applied it to many production and decay processes: SUSY-QCD: gluon and gluino one-loop contributions, e.g. Higgs decays into fermions and sfermions Sfermion decays into chargino, neutralino, W, Z, and Higgs bosons (also crossed channels studied) 3rd gen, sfermion production at a LC Problem with convergence: Resummation necessary – Improvement worked out

  10. Yukawa type corrections: calculated examples are Sfermion pair prod. at a LC Single Higgs boson prod. at a LC Full one-loop corrections: very complex calculations, done by hand and checked by automatic tools: A0 decay to sfermion pair other Higgs decay channels to sfermions in progress Higgs decays to charginos and neutralinos (still in progress) Sfermion, chargino and neutralino pair productions in e+e- annihilations

  11. - applied to e.g. H+ to t b, t nt e+e- to tops, charginos, and neutralinos, and additonal decays CP Violation: The SM cannot explain sufficiently CP viol. which is a necessary ingredient for the particle-antiparticle asymmetry built by baryogenesis (or leptogenesis). Many complex parameters in general SUSY – sources for CP violation Lepton Flavour Violation: CP sensitive observables proposed by our group (Triple products, …) Lepton Flavour Violation: Mass matrices of charged leptons allow large LFV despite the strong bounds of rare decays like m-to e- g A possible signatur: e+e-to e+m- Also combined studies on CP and LFV

  12. Contributions to workshops: We are a small group. Despite this fact participated in workshops on LEP, LHC, LC, CLIC and muon collider W. M. – convenor activity EU project: member of the running EU network RMT on collider physics New project has been submitted this year

  13. International collaborations Y. Yamada, K. Hidaka - Japan T. Gajdosik – Vilnius, Lithuania D. Denegri - CMS - CERN W. Porod - Zürich H. Fraas, O. Kittel - Würzburg G. Moortgat-Pick - Durham J. Valle - Valencia U. Martyn, L. Rurua – DESY Hamburg M. Beccaria - Lecce C. Verzegnassi - Trieste F. Renard - Montpellier V. Spanos - Minneapolis EU Marie-Curie fellowship at Hephy Vienna 2001-2003

  14. HEP Publications 1999-2004 we get from the web

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