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Updated Bs -mixing constraints on new physics models for b→sℓ+ℓ− anomalies

Di Luzio, Luca; Kirk, Matthew; Lenz, Alexander

Updated Bs -mixing constraints on new physics models for b→sℓ+ℓ− anomalies Thumbnail


Luca Di Luzio

Matthew Kirk

Alexander Lenz


Many new physics models that explain the intriguing anomalies in the b-quark flavor sector are severely constrained by Bs mixing, for which the Standard Model prediction and experiment agreed well until recently. The most recent Flavour Lattice Averaging Group (FLAG) average of lattice results for the nonperturbative matrix elements points, however, in the direction of a small discrepancy in this observable Cabibbo-Kobayashi-Maskawa (CKM). Using up-to-date inputs from standard sources such as PDG, FLAG and one of the two leading CKM fitting groups to determine ΔMSM s , we find a severe reduction of the allowed parameter space of Z0 and leptoquark models explaining the B anomalies. Remarkably, in the former case the upper bound on the Z0 mass approaches dangerously close to the energy scales already probed by the LHC. We finally identify some model-building directions in order to alleviate the tension with Bs mixing.


Di Luzio, L., Kirk, M., & Lenz, A. (2018). Updated Bs -mixing constraints on new physics models for b→sℓ+ℓ− anomalies. Physical Review D, 97(9), Article 095035.

Journal Article Type Article
Online Publication Date May 25, 2018
Publication Date May 25, 2018
Deposit Date Jun 7, 2018
Publicly Available Date Jun 7, 2018
Journal Physical Review D
Print ISSN 2470-0010
Electronic ISSN 2470-0029
Publisher American Physical Society
Peer Reviewed Peer Reviewed
Volume 97
Issue 9
Article Number 095035


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Copyright Statement
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

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