https://doi.org/10.1140/epjc/s10052-016-4207-5
Regular Article - Theoretical Physics
and matching at 
1
IPNL, CNRS/IN2P3, 4 rue E. Fermi, 69622, Villeurbanne Cedex, France
2
Université Lyon 1, Villeurbanne, France
3
Université de Lyon, 69622, Lyon, France
* e-mail: s.davidson@ipnl.in2p3.fr
Received:
18
March
2016
Accepted:
14
June
2016
Published online:
4
July
2016
Several experiments search for 
flavour change, for instance in 
, and 
. This paper studies how to translate these experimental constraints from low energy to a New Physics scale 
. A basis of QCD 
QED-invariant operators (as appropriate below 
) is reviewed, then run to with one-loop Renormalisation Group Equations (RGEs) of QCD and QED. At , these operators are matched onto SU(2)-invariant dimension-six operators, which can continue to run up with electroweak RGEs. As an example, the bound is translated to the scale M, where it constrains two sums of operators. The constraints differ from those obtained in previous EFT analyses of , but they reproduce the expected bounds on flavour-changing interactions of the Z and the Higgs, because the matching at is pragmatically performed to the loop order required to get the “leading” contribution.
© The Author(s), 2016
