Last modified 5 years ago Last modified on 09/12/12 00:59:22

Effective field theory for weak boson pair production

Author : Celine Degrande

References :

  • C. Degrande, N. Greiner, W. Kilian, O. Mattelaer, H. Mebane, T. Stelzer, S. Willenbrock, C. Zhang, arXiv:1205.4231 [hep-ph]


This !MadGraph5 model is the implementation of the weak boson effective field theory described in arXiv:1205.4231 [hep-ph]. Namely, the model contains all the five dimension-six operators that modify the triple gauge boson vertices. Their coefficients can be set in the param_card.dat. The parameters in the param_card are the full coefficients, i.e. $c_i/\Lambda^2$ and are in TeV$^-2$. The name are self-explanatory, $c_{WWW}/\Lambda^2$ is called CWWWL2 and similarly for $c_W$ and $c_B$, the coefficients of the CP violating operators $O_{\tilde{W}WW}$ and $O_{\tilde{W}}$ are CPWWWL2 and CPWL2 respectively. The new interaction has also an order NP (for new physics) which is the power of ($1/\Lambda$) of the amplitude. For example, an amplitude with one vertex for a dimension-six operator is proportional to $1/\Lambda^2$ and has NP=2.

To use the model online,you need to choose "Weak Bosons Effective Field theory (dim 6)" as the model. If you run !MadGraph5 locally (via a shell), the name of the model is EWdim6 (so you need to use the command import model EWdim6)

Operator Coefficient param_card name limit at 68% C.L.(TeV$^{-2}$)
$\mbox{Tr}[W_{\mu\nu}W^{\nu\rho}W_{\rho}^{\mu}]$ $c_{WWW}/\Lambda^2$ CWWWL2 [-11.9 , -1.94]
$(D_\mu\Phi)^\dagger W^{\mu\nu}(D_\nu\Phi)$ $c_{W}/\Lambda^2$ CWL2 [-8.42 , 1.44]
$(D_\mu\Phi)^\dagger B^{\mu\nu}(D_\nu\Phi)$ $c_{B}/\Lambda^2$ CBL2 [-7.9 , 14.9]
$\mbox{Tr}[\tilde{W}_{\mu\nu}W^{\nu\rho}W_{\rho}^{\mu}]$ $c_{\tilde{W}WW}/\Lambda^2$ CPWWWL2 [-185.3 , -82.4]
$(D_\mu\Phi)^\dagger \tilde{W}^{\mu\nu}(D_\nu\Phi)$ $c_{\tilde{W}}/\Lambda^2$ CPWL2 [-39.3 , -4.9]

The limits have been obtained by inverting the values of the anomalous couplings from the PDG 2012.