Göttingen 2012 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 21: Astroteilchenphysik, Kosmologie / Neutrinophysik (Theorie)
T 21.8: Vortrag
Dienstag, 28. Februar 2012, 18:30–18:45, VG 3.101
Natural Vacuum Alignment from Group Theory: The Minimal Case — •Martin Holthausen1 and Michael A. Schmidt2 — 1Max-Planck Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany — 2ARC Centre of Excellence for Particle Physics at the Terascale, School of Physics, The University of Melbourne, Victoria 3010, Australia
Discrete flavour symmetries have been proven successful in explaining the leptonic flavour structure. To account for the observed mixing pattern, the flavour symmetry has to be broken to different subgroups in the charged and neutral lepton sector. This, however, poses a problem as cross-couplings via non-trivial contractions in the scalar potential force the group to break to the same subgroup. We present a solution to this problem by extending the flavour group in such a way that it preserves the flavour structure, but leads to an ’accidental’ symmetry in the flavon potential.
We have searched for symmetry groups up to order 1000, which forbid all dangerous cross-couplings and extend one of the interesting groups A4, T7, S4, T′ or Δ(27). We have found a number of candidate groups and present a model based on one of the smallest extension of A4, namely Q8 A4. We show that the most general non-supersymmetric potential allows for the correct vacuum alignment. We investigate the effects of higher dimensional operators on the vacuum configuration and mixing angles, and give a see-saw-like UV completion. Finally, we discuss the supersymmetrization of the model and present the Mathematica package Discrete.