RK and RK* beyond the standard model
Abstract
Measurements of the ratio of B →K*μ μ to B →K*e e branching fractions, RK*, by the LHCb Collaboration strengthen the hints from previous studies with pseudoscalar kaons, RK, for the breakdown of lepton universality, and therefore the Standard Model (SM), to ∼3.5 σ . Complementarity between RK and RK* allows us to pin down the Dirac structure of the new contributions to be predominantly SM-like chiral, with possible admixture of chirality-flipped contributions of up to O (few 10 %). Scalar and vector leptoquark representations (S3,V1,V3) plus possible (S∼2,V2) admixture can explain RK ,K* via tree-level exchange. Flavor models naturally predict leptoquark masses not exceeding a few TeV, with couplings to third-generation quarks at O (0.1 ), implying that this scenario can be directly tested at the LHC.
- Publication:
-
Physical Review D
- Pub Date:
- August 2017
- DOI:
- 10.1103/PhysRevD.96.035003
- arXiv:
- arXiv:1704.05444
- Bibcode:
- 2017PhRvD..96c5003H
- Keywords:
-
- High Energy Physics - Phenomenology
- E-Print:
- v1: 8 pages, v2: references added, typos corrected, matches published version