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dc.contributor.authorAlgueró, M
dc.contributor.authorCartelle, PA
dc.contributor.authorMarshall, AM
dc.contributor.authorMasjuan, P
dc.contributor.authorMatias, J
dc.contributor.authorMcCann, MA
dc.contributor.authorPatel, M
dc.contributor.authorPetridis, KA
dc.contributor.authorSmith, M
dc.date.accessioned2022-01-04T14:33:24Z
dc.date.available2022-01-04T14:33:24Z
dc.date.issued2021-12-13
dc.date.submitted2021-07-13
dc.identifier.issn1029-8479
dc.identifier.otherjhep12(2021)085
dc.identifier.other17356
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/331906
dc.description.abstract<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>In this paper we present a detailed study of the four-body decay <jats:italic>B</jats:italic><jats:sup>0</jats:sup> → <jats:italic>K</jats:italic><jats:sup>+</jats:sup><jats:italic>π</jats:italic><jats:sup><jats:italic>−</jats:italic></jats:sup><jats:italic>ℓ</jats:italic><jats:sup>+</jats:sup><jats:italic>ℓ</jats:italic><jats:sup><jats:italic>−</jats:italic></jats:sup>, where tensions with the Standard Model predictions have been observed. Our analysis of the decay with P- and S-wave contributions to the <jats:italic>K</jats:italic><jats:sup>+</jats:sup><jats:italic>π</jats:italic><jats:sup><jats:italic>−</jats:italic></jats:sup> system develops a complete understanding of the symmetries of the distribution, in the case of massless and massive leptons. In both cases, the symmetries determine relations between the observables in the <jats:italic>B</jats:italic><jats:sup>0</jats:sup> → <jats:italic>K</jats:italic><jats:sup>+</jats:sup><jats:italic>π</jats:italic><jats:sup><jats:italic>−</jats:italic></jats:sup><jats:italic>ℓ</jats:italic><jats:sup>+</jats:sup><jats:italic>ℓ</jats:italic><jats:sup><jats:italic>−</jats:italic></jats:sup> decay distribution. This enables us to define the complete set of observables accessible to experiments, including several that have not previously been identified. The new observables arise when the decay rate is written differentially with respect to <jats:inline-formula><jats:alternatives><jats:tex-math>$$ {m}_{K_{\pi }} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>m</mml:mi> <mml:msub> <mml:mi>K</mml:mi> <mml:mi>π</mml:mi> </mml:msub> </mml:msub> </mml:math></jats:alternatives></jats:inline-formula>. We demonstrate that experiments will be able to fit this full decay distribution with currently available data sets and investigate the sensitivity to new physics scenarios given the experimental precision that is expected in the future.</jats:p><jats:p>The symmetry relations provide a unique handle to explore the behaviour of S-wave observables by expressing them in terms of P-wave observables, therefore minimising the dependence on poorly-known S-wave form factors. Using this approach, we construct two theoretically optimized S-wave observables and explore their sensitivity to new physics. By further exploiting the symmetry relations, we obtain the first bounds on the S-wave observables using two different methods and highlight how these relations may be used as cross-checks of the experimental methodology and the parametrization of the <jats:italic>B</jats:italic><jats:sup>0</jats:sup> → <jats:italic>K</jats:italic><jats:sup>+</jats:sup><jats:italic>π</jats:italic><jats:sup><jats:italic>−</jats:italic></jats:sup><jats:italic>ℓ</jats:italic><jats:sup>+</jats:sup><jats:italic>ℓ</jats:italic><jats:sup><jats:italic>−</jats:italic></jats:sup> differential decay rate. We identify a zero-crossing point that would be at a common dilepton invariant mass for a subset of P- and S-wave observables, and explore the information on new physics and hadronic effects that this zero point can provide.</jats:p>
dc.languageen
dc.publisherSpringer Science and Business Media LLC
dc.subjectRegular Article - Theoretical Physics
dc.subjectEffective Field Theories
dc.subjectHeavy Quark Physics
dc.titleA complete description of P- and S-wave contributions to the B <sup>0</sup> → K <sup>+</sup> π <sup>−</sup> ℓ <sup>+</sup> ℓ <sup>−</sup> decay
dc.typeArticle
dc.date.updated2022-01-04T14:33:24Z
prism.issueIdentifier12
prism.publicationNameJournal of High Energy Physics
prism.volume2021
dc.identifier.doi10.17863/CAM.79356
dcterms.dateAccepted2021-11-20
rioxxterms.versionofrecord10.1007/JHEP12(2021)085
rioxxterms.versionVoR
rioxxterms.licenseref.urihttp://creativecommons.org/licenses/by/4.0/
dc.contributor.orcidAlgueró, M [0000-0001-7519-3845]
dc.identifier.eissn1029-8479
cam.issuedOnline2021-12-13
dc.identifier.arxiv2107.05301


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