https://doi.org/10.1140/epjc/s10052-014-2945-9
Regular Article - Theoretical Physics
Dipole operator constraints on composite Higgs models
1
PRISMA Cluster of Excellence and Mainz Institute for Theoretical Physics, Johannes Gutenberg University, 55099 , Mainz, Germany
2
Department of Physics, LEPP, Cornell University, Ithaca, NY, 14853, USA
3
Excellence Cluster Universe, Technische Universität München, Boltzmannstr. 2, 85748 , Garching, Germany
* e-mail: david.straub@tum.de
Received:
25
March
2014
Accepted:
17
June
2014
Published online:
23
July
2014
Flavour- and CP-violating electromagnetic or chromomagnetic dipole operators in the quark sector are generated in a large class of new physics models and are strongly constrained by measurements of the neutron electric dipole moment and observables sensitive to flavour-changing neutral currents, such as the 
branching ratio and 
. After a model-independent discussion of the relevant constraints, we analyze these effects in models with partial compositeness, where the quarks get their masses by mixing with vector-like composite fermions. These scenarios can be seen as the low-energy limit of composite Higgs or warped extra dimensional models. We study different choices for the electroweak representations of the composite fermions motivated by electroweak precision tests as well as different flavour structures, including flavour anarchy and 
or 
flavour symmetries in the strong sector. In models with “wrong-chirality” Yukawa couplings, we find a strong bound from the neutron electric dipole moment, irrespective of the flavour structure. In the case of flavour anarchy, we also find strong bounds from flavour-violating dipoles, while these constraints are mild in the flavour-symmetric models.
© SIF and Springer-Verlag Berlin Heidelberg, 2014
