http://arxiv.org/abs/1705.03897
We study a broad class of vector portal models where the Standard Model (SM) gauge symmetry is extended with a new abelian group $U(1)’$. We augment the SM field content by an arbitrary number of scalars and fermions that are singlets under the SM and charged only under the $U(1)’$, potentially including dark matter (DM) candidates. We emphasize the importance of theoretical issues such as the classical gauge invariance of the full Lagrangian, anomaly cancellation and S-matrix unitarity, which apply to $U(1)’$ spontaneously broken at different mass scales. These considerations are shown to generally have profound consequences on the phenomenology. The condition of cancelling gauge anomalies leads to compact relations among the $U(1)’$ charges of the SM fields and dark fermion fields, and puts a lower bound on the number of dark fermion species. Contrary to naive expectations, the generically present DM annihilation to $Z h$ is found to be p-wave suppressed, as hinted by perturbative unitarity of S-matrix, with dramatic implications for DM thermal relic density and indirect searches. Finally, we specify a UV-complete benchmark model, and explore its phenomenology, including DM direct and indirect detections and searches at the Large Hadron Collider (LHC). Within this framework, the interplay between dark matter, new vector boson and Higgs physics is rather natural and generic.
Y. Cui and F. DEramo
Fri, 12 May 17
10/55
Comments: 5 pages, 3 figures
You must be logged in to post a comment.