Bi-galileon theory II: phenomenology

Padilla, Antonio; Saffin, Paul M.; Zhou, Shuang-Yong

Abstract

We continue to introduce bi-galileon theory, the generalisation of the single galileon model introduced by Nicolis et al. The theory contains two coupled scalar fields and is described by a Lagrangian that is invariant under Galilean shifts in those fields. This paper is the second of two, and focuses on the phenomenology of the theory. We are particularly interesting in models that admit solutions that are asymptotically self accelerating or asymptotically self tuning. In contrast to the single galileon theories, we find examples of self accelerating models that are simultaneously free from ghosts, tachyons and tadpoles, able to pass solar system constraints through Vainshtein screening, and do not suffer from problems with superluminality, Cerenkov emission or strong coupling. We also find self tuning models and discuss how Weinberg's no go theorem is evaded by breaking Poincar\'e invariance in the scalar sector. Whereas the galileon description is valid all the way down to solar system scales for the self-accelerating models, unfortunately the same cannot be said for self tuning models owing to the scalars backreacting strongly on to the geometry.

Citation

Padilla, A., Saffin, P. M., & Zhou, S.-Y. (2011). Bi-galileon theory II: phenomenology. Journal of High Energy Physics, 2011(1), https://doi.org/10.1007/JHEP01%282011%29099

• Journal Article Type: Article
• Acceptance Date: Jan 1, 2011
• Publication Date: Jan 24, 2011
• Deposit Date: Apr 21, 2017
• Publicly Available Date: Apr 21, 2017
• Journal: Journal of High Energy Physics
• Electronic ISSN: 1029-8479
• Publisher: Springer Verlag
• Peer Reviewed: Peer Reviewed
• Volume: 2011
• Issue: 1
• DOI: https://doi.org/10.1007/JHEP01%282011%29099
• Public URL: https://nottingham-repository.worktribe.com/output/707120
• Publisher URL: http://link.springer.com/article/10.1007%2FJHEP01%282011%29099
• Contract Date: Apr 21, 2017