taken to exclude everything above their sensitivity. However, the upper limit of eqn (\[plage\]) is relevant for collider searches, where $\hat{s}$ is the invariant mass of the invisibles. This upper limit is rarely taken into account in the literature.

The first step in the EFT recipe to parametrise New Physics from beyond the scale $\Lambda$ it to add to the Lagrangian (at the scale $\Lambda$), all the non-renormalisable operators which can be constructed out of the fields present, consistently with the symmetries of the theory[@Georgi]. The coefficients $C^{(n)}_O$ of these operators are unknown “coupling constants” which evolve with scale via Renormalisation Group Equations. This infinite set of operators would be unmanageable, so EFT is useful when there is a hierachy between the experimental and NP scales. Then only the lowest dimension operators need be considered.

In this note, the dark matter is assumed to be the only new New Physics particle lighter than a TeV, and is taken to be a SM gauge singlet dirac fermion $\chi$ with a conserved parity, and of mass $m_\chi \geq m_Z/2$ (maybe $\geq m_h/2$), to avoid bounds on the coupling to the $Z$ from the invisible width[^3] of the $Z$ (and Higgs). So the 