Sebastian Jäger
Charming new B-physics
Jäger, Sebastian; Kirk, Matthew; Lenz, Alexander; Leslie, Kirsten
Authors
Matthew Kirk
Alexander Lenz
Kirsten Leslie
Abstract
We give a comprehensive account of the flavour physics of Beyond-Standard-Model (BSM) effects in b → cc¯¯cs transitions, considering the full set of 20 four-quark operators. We discuss the leading-order structure of their RG mixing with each other as well as the QCD-penguin, dipole, and FCNC semileptonic operators they necessarily mix with, providing compact expressions. We also provide the first complete results for BSM effects in the lifetime observables ∆Γs and τ (Bs)/τ(Bd), as well as for the semileptonic CP-asymmetry assl. From a global analysis, we obtain stringent constraints on 16 of the 20 BSM operators, including the 10 operators Qc′1…10 involving a right-handed strange quark. Focussing on CP-conserving new physics, the constraints correspond to NP scales of order 10 TeV in most cases, always dominated by exclusive and/or radiative B-decays via RGE mixing. For the remaining four operators, including the two Standard-Model (SM) ones, larger effects are experimentally allowed, as previously noted in [1]. We extend that paper’s scope to the CP-violating case, paying attention to the impact on the decay rate and time-dependent CP-violation in Bd → J/ψKS. Contrary to common lore, we show that quantifiable constraints arise for new physics in either of the two SM operators, with the uncertain non-perturbative matrix element of the colour-suppressed (or equivalently, colour-octet) operator determined from the data. For new physics in the coefficient Cc1, suppressed in the SM, we find (in addition to CP-conserving new physics) two perfectly viable, narrow bands of complex Wilson coefficients. Somewhat curiously, one of them contains a region where the fitted matrix element for the colour-suppressed operator is in agreement with naive factorization, contrarily to a widely held belief that large non- factorizable contributions to Bd → J/ψKS are implied by experimental data.
Citation
Jäger, S., Kirk, M., Lenz, A., & Leslie, K. (2020). Charming new B-physics. Journal of High Energy Physics, 2020(3), Article 122. https://doi.org/10.1007/jhep03%282020%29122
Journal Article Type | Article |
---|---|
Acceptance Date | Feb 25, 2020 |
Online Publication Date | Mar 23, 2020 |
Publication Date | Mar 31, 2020 |
Deposit Date | Mar 24, 2020 |
Publicly Available Date | Mar 24, 2020 |
Journal | Journal of High Energy Physics |
Print ISSN | 1126-6708 |
Publisher | Scuola Internazionale Superiore di Studi Avanzati (SISSA) |
Peer Reviewed | Peer Reviewed |
Volume | 2020 |
Issue | 3 |
Article Number | 122 |
DOI | https://doi.org/10.1007/jhep03%282020%29122 |
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Copyright Statement
This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.
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