dc.contributor.author Davis, Anne dc.contributor.author Melville, Scott dc.date.accessioned 2022-02-21T12:27:41Z dc.date.available 2022-02-21T12:27:41Z dc.date.issued 2021-11 dc.date.submitted 2021-07-04 dc.identifier.issn 1475-7516 dc.identifier.other jcap_009p_0721 dc.identifier.other jcap_009p_0721 dc.identifier.uri https://www.repository.cam.ac.uk/handle/1810/334271 dc.description.abstract Low-energy effective field theories containing a light scalar field are used extensively in cosmology, but often there is a tension between embedding such theories in a healthy UV completion and achieving a phenomenologically viable screening mechanism in the IR. Here, we identify the range of interaction couplings which allow for a smooth resummation of classical non-linearities (necessary for kinetic/Vainshtein-type screening), and compare this with the range allowed by unitarity, causality and locality in the underlying UV theory. The latter region is identified using positivity bounds on the $2\to2$ scattering amplitude, and in particular by considering scattering about a non-trivial background for the scalar we are able to place constraints on interactions at all orders in the field (beyond quartic order). We identify two classes of theories can both exhibit screening and satisfy existing positivity bounds, namely scalar-tensor theories of $P(X)$ or quartic Horndeski type in which the leading interaction contains an odd power of $X$. Finally, for the quartic DBI Galileon (equivalent to a disformally coupled scalar in the Einstein frame), the analogous resummation can be performed near two-body systems and imposing positivity constraints introduces a non-perturbative ambiguity in the screened scalar profile. These results will guide future searches for UV complete models which exhibit screening of fifth forces in the IR. dc.language en dc.publisher IOP Publishing dc.subject paper dc.subject particle physics - cosmology connection dc.subject dark energy theory dc.subject modified gravity dc.title Scalar fields near compact objects: Resummation versus UV completion dc.type Article dc.date.updated 2022-02-21T12:27:41Z prism.issueIdentifier 11 prism.publicationName Journal of Cosmology and Astroparticle Physics prism.volume 2021 dc.identifier.doi 10.17863/CAM.81684 dcterms.dateAccepted 2021-09-15 rioxxterms.versionofrecord 10.1088/1475-7516/2021/11/012 rioxxterms.version VoR rioxxterms.licenseref.uri http://creativecommons.org/licenses/by/4.0/ dc.contributor.orcid Melville, Scott [0000-0003-3516-856X] dc.identifier.eissn 1475-7516 dc.publisher.url http://dx.doi.org/10.1088/1475-7516/2021/11/012 cam.issuedOnline 2021-11-08
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