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New physics effects in tree-level decays and the precision in the determination of the quark mixing angle γ

Brod, Joachim; Lenz, Alexander; Tetlalmatzi-Xolocotzi, Gilberto; Wiebusch, Martin

New physics effects in tree-level decays and the precision in the determination of the quark mixing angle γ Thumbnail


Authors

Joachim Brod

Alexander Lenz

Gilberto Tetlalmatzi-Xolocotzi

Martin Wiebusch



Abstract

We critically review the assumption that no new physics is acting in tree-level B-meson decays and study the consequences for the ultimate precision in the direct determination of the Cabibbo-Kobayashi-Maskawa (CKM) angle γ. In our exploratory study we find that sizeable universal new physics contributions, ΔC1,2, to the tree-level Wilson coefficients C1,2 of the effective Hamiltonian describing weak decays of the b quark are currently not excluded by experimental data. In particular, we find that ImΔC1 and ImΔC2 can easily be of order ±10% without violating any constraints from data. Such a size of new physics effects in C1 and C2 corresponds to an intrinsic uncertainty in the CKM angle γ of the order of |δγ|≈4°, which is slightly below the current experimental precision. The accuracy in the determination of γ can be improved by putting stronger constraints on the tree-level Wilson coefficients, in particular C1. To this end we suggest a more refined theoretical study as well as more precise measurements of the observables that currently provide the strongest bounds on hypothetical new weak phases in C1 and C2. We note that the semileptonic CP asymmetries seem to have the best prospect for improving the bound on the weak phase in C1.

Citation

Brod, J., Lenz, A., Tetlalmatzi-Xolocotzi, G., & Wiebusch, M. (2015). New physics effects in tree-level decays and the precision in the determination of the quark mixing angle γ. Physical Review D, 92(3), Article 033002. https://doi.org/10.1103/physrevd.92.033002

Journal Article Type Article
Online Publication Date Aug 3, 2015
Publication Date Aug 3, 2015
Deposit Date Dec 4, 2015
Publicly Available Date Mar 29, 2024
Journal Physical Review D
Print ISSN 1550-7998
Electronic ISSN 1550-2368
Publisher American Physical Society
Peer Reviewed Peer Reviewed
Volume 92
Issue 3
Article Number 033002
DOI https://doi.org/10.1103/physrevd.92.033002

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Copyright Statement
Reprinted with permission from the American Physical Society: Physical Review D 92, 033002 © 2015 by the American Physical Society. Readers may view, browse, and/or download material for temporary copying purposes only, provided these uses are for noncommercial personal purposes. Except as provided by law, this material may not be further reproduced, distributed, transmitted, modified, adapted, performed, displayed, published, or sold in whole or part, without prior written permission from the American Physical Society.






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