Composite leptoquarks and anomalies in B-meson decays

• Published in: The journal of high energy physics Vol. 2015; no. 5; p. 1
• Main Authors: Gripaios, Ben, Nardecchia, M., Renner, S. A.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 04-05-2015; Springer Nature B.V
• Subjects: Classical and Quantum Gravitation; Elementary Particles; High energy physics; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Regular Article - Theoretical Physics; Relativity Theory; String Theory; Beyond Standard Model; Technicolor and Composite Models; B-Physics
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP05(2015)006

A
bstract
We attempt to explain recent anomalies in semileptonic
B
decays at LHCb via a composite Higgs model, in which both the Higgs and an SU(2)
L
-triplet leptoquark arise as pseudo-Goldstone bosons of the strong dynamics. Fermion masses are assumed to be generated via the mechanism of partial compositeness, which largely determines the leptoquark couplings and implies non-universal lepton interactions. The latter are needed to accommodate tensions in the
b
→
sμμ
dataset and to be consistent with a discrepancy measured at LHCb in the ratio of
B
+
→
K
+
μ
+
μ
−
to
B
+
→
K
+
e
+
e
−
branching ratios. The data imply that the leptoquark should have a mass of around a TeV. We find that the model is not in conflict with current flavour or direct production bounds, but we identify a few observables for which the new physics contributions are close to current limits and where the leptoquark is likely to show up in future measurements. The leptoquark will be pair-produced at the LHC and decay predominantly to third-generation quarks and leptons, and LHC13 searches will provide further strong bounds.