We discuss the constraints on the Standard Model Effective Field Theory inferred from global fits to electroweak data. Special attention is paid to two unconstrained combinations of Wilson coefficients that are present when the analysis is restricted to measurements of ψψ ¯ → ψψ ¯ scatterings. We illustrate how these unconstrained directions arise due to a reparameterization invariance that characterizes ψψ ¯ → ψψ ¯ processes but is not respected in ψψ ¯ → ψψ ¯ ψψ ¯ scatterings. This invariance is independent of the operator basis adopted and of the choice of the input parameters. This is verified comparing the results obtained in the {αem,m Z,ĜF} input scheme with those of a {mW,m Z,ĜF} scheme.
Brivio I. (2017). Scheming in the smeft. Sissa Medialab Srl [10.22323/1.314.0431].
Scheming in the smeft
Brivio I.
2017
Abstract
We discuss the constraints on the Standard Model Effective Field Theory inferred from global fits to electroweak data. Special attention is paid to two unconstrained combinations of Wilson coefficients that are present when the analysis is restricted to measurements of ψψ ¯ → ψψ ¯ scatterings. We illustrate how these unconstrained directions arise due to a reparameterization invariance that characterizes ψψ ¯ → ψψ ¯ processes but is not respected in ψψ ¯ → ψψ ¯ ψψ ¯ scatterings. This invariance is independent of the operator basis adopted and of the choice of the input parameters. This is verified comparing the results obtained in the {αem,m Z,ĜF} input scheme with those of a {mW,m Z,ĜF} scheme.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
