https://doi.org/10.1140/epjc/s10052-020-7817-x
Regular Article - Theoretical Physics
B-decay discrepancies after Moriond 2019
1
Excellence Cluster Universe, Boltzmannstr. 2, 85748, Garching, Germany
2
Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, CA, 95064, USA
3
Laboratoire d’Annecy-le-Vieux de Physique Théorique, UMR5108, CNRS, 9 Chemin de Bellevue, B.P. 110, 74941, Annecy-le-Vieux Cedex, France
* e-mail: diego.guadagnoli@lapth.cnrs.fr
Received:
26
December
2019
Accepted:
6
March
2020
Published online:
19
March
2020
Following the updated measurement of the lepton flavour universality (LFU) ratio 
in 
decays by LHCb, as well as a number of further measurements, e.g. 
by Belle and 
by ATLAS, we analyse the global status of new physics in 
transitions in the weak effective theory at the b-quark scale, in the Standard Model effective theory above the electroweak scale, and in simplified models of new physics. We find that the data continues to strongly prefer a solution with new physics in semi-leptonic Wilson coefficients. A purely muonic contribution to the combination 
, well suited to UV-complete interpretations, is now favoured with respect to a muonic contribution to 
only. An even better fit is obtained by allowing an additional LFU shift in . Such a shift can be renormalization-group induced from four-fermion operators above the electroweak scale, in particular from semi-tauonic operators, able to account for the potential discrepancies in 
transitions. This scenario is naturally realized in the simplified 
leptoquark model. We also analyse simplified models where a LFU effect in 
is induced radiatively from four-quark operators and show that such a setup is on the brink of exclusion by LHC di-jet resonance searches.
© The Author(s), 2020
