Abstract
In the context of the Standard Model effective field theory we derive direct and indirect bounds on chromodipole operators involving the bottom and charm quark. We find that the experimental upper limit on the neutron electric dipole moment puts severe constraints on the imaginary parts of the Wilson coefficients of both chromodipole operators. The magnitudes of the Wilson coefficients are instead only weakly constrained by dijet searches and Z-boson production in association with bottom-quark jets. Flavour physics does not provide meaningful bounds.
Highlights
In contrast to the SMEFT Yukawa-type operators that can only be constrained by processes involving a Higgs or Higgses both real or virtual, the operators (1.1) can be bounded by measurements of observables that involve bottom quarks and possibly other particles but no Higgs boson
We find that the experimental upper limit on the neutron electric dipole moment puts severe constraints on the imaginary parts of the Wilson coefficients of both chromodipole operators
We summarise the limits on the Wilson coefficients of the operators QbG and QcG that we have derived in the course of this work
Summary
Jet physics has previously been used to put constraints on SMEFT operators [13,14,15,16,17,18]. The dijet angular distribution has the salient advantage that it allows to constrain broad s-channel resonances or modifications in the spectrum due to the presence of higherdimensional operators in a rather model-independent fashion This is due to the fact that the dominant channels in QCD dijet production have the familiar Rutherford scattering behaviour dσ/d cos θ ∝ 1/ sin θ/2 at small angle θ, which is characteristic for t-channel exchange of a massless spin-one boson. To find the 95% confidence level (CL) limit on the magnitude of the Wilson coefficient of the dipole operator QbG, we perform a χ2 fit to the normalised angular distribution in all seven dijet invariant mass bins, including both experimental and theoretical uncertainties. Since the focus of this work lies on deriving constraints on the chromodipole operators involving bottom and charm quarks, we do not entertain this possibility here
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