Version 7 (modified by martinbauer, 5 weeks ago) (diff)

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## Anomaly Free Z prime Model

### Autors

• Martin Bauer
• Durham University
• martin.m.bauer@...
• Sascha Diefenbacher
• Universität Hamburg
• sascha.daniel.diefenbacher@...
• Tilman Plehn
• Universität Heidelberg
• plehn@...
• Michael Russell
• Daniel A. Camargo

### Model Description

We consider consistent dark matter models with a spin-1 mediator Z' and a dark matter fermion χ, charged under the new gauge group. The available options are purely singlet SM fermions, gauged lepton number differences, or the well-known anomaly-free difference between the lepton and baryon numbers

The $Z'$ couplings to currents of SM fermionsare given by:

where $g_{Z'}$ denotes the dark gauge coupling. The different coupling structures shown above can be understood in terms of a flavor structure of a dark gauge coupling matrix.

The fermion current structure can be generalized to include the dark matter current. To couple to the gauge mediator the dark matter fermion has to be a Dirac fermion. To avoid new anomalies, the dark matter candidate cannot be chiral and its charges under the new gauge group are $q_{\chi_L}=q_{\chi_R}$. This defines a dark fermion Lagrangian with a vector mass term

with the covariant derivative of the SM-singlet fermion

In all cases, the kinetic term for the $U(1)$ gauge bosons is not canonically normalized