Bi-galileon theory II: phenomenology

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 focus...

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Main Authors: Padilla, Antonio, Saffin, Paul M., Zhou, Shuang-Yong
Format: Article
Published: Springer 2011
Online Access:https://eprints.nottingham.ac.uk/42135/
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author Padilla, Antonio
Saffin, Paul M.
Zhou, Shuang-Yong
author_facet Padilla, Antonio
Saffin, Paul M.
Zhou, Shuang-Yong
author_sort Padilla, Antonio
building Nottingham Research Data Repository
collection Online Access
description 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.
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spelling nottingham-421352020-05-04T16:30:15Z https://eprints.nottingham.ac.uk/42135/ Bi-galileon theory II: phenomenology Padilla, Antonio Saffin, Paul M. Zhou, Shuang-Yong 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. Springer 2011-01-24 Article PeerReviewed Padilla, Antonio, Saffin, Paul M. and Zhou, Shuang-Yong (2011) Bi-galileon theory II: phenomenology. Journal of High Energy Physics, 2011 (1). 099. ISSN 1029-8479 http://link.springer.com/article/10.1007%2FJHEP01%282011%29099 doi:10.1007/JHEP01(2011)099 doi:10.1007/JHEP01(2011)099
spellingShingle Padilla, Antonio
Saffin, Paul M.
Zhou, Shuang-Yong
Bi-galileon theory II: phenomenology
title Bi-galileon theory II: phenomenology
title_full Bi-galileon theory II: phenomenology
title_fullStr Bi-galileon theory II: phenomenology
title_full_unstemmed Bi-galileon theory II: phenomenology
title_short Bi-galileon theory II: phenomenology
title_sort bi-galileon theory ii: phenomenology
url https://eprints.nottingham.ac.uk/42135/
https://eprints.nottingham.ac.uk/42135/
https://eprints.nottingham.ac.uk/42135/