https://doi.org/10.1140/epjp/i2014-14262-4
Regular Article
The physics of the θ-angle for composite extensions of the standard model
1
The Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100, Copenhagen, Denmark
2
Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-106 91, Stockholm, Sweden
3
CP3-Origins & the Danish Institute for Advanced Study DIAS, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark
* e-mail: divecchi@nordita.org
Received:
19
September
2014
Revised:
21
October
2014
Accepted:
15
November
2014
Published online:
8
December
2014
We analyse the θ-angle physics associated to extensions of the standard model of particle interactions featuring new strongly coupled sectors. We start by providing a pedagogical review of the θ-angle physics for Quantum Chromodynamics (QCD) including also the axion properties. We then move to analyse composite extensions of the standard model elucidating the interplay between the new θ-angle with the QCD one. We consider first QCD-like dynamics and then generalise it to consider several kinds of new strongly coupled gauge theories with fermions transforming according to different matter representations. Our analysis is of immediate use for different models of composite Higgs dynamics, composite dark matter and inflation.
© Società Italiana di Fisica and Springer-Verlag Berlin Heidelberg, 2014
