Dark Matter and enhanced h -> gamma gamma rate from vector-like Leptons
journal contributionposted on 2013-12-13, 00:00 authored by Aniket Joglekar, Pedro Schwaller, Carlos E. M. Wagner
In this paper, we study an extension of the standard model with a vector-like generation of leptons. This model provides a viable dark matter candidate and a possibility to enhance the Higgs decay rate into a pair of photons. We evaluate constraints from electroweak precision tests and from vacuum stability, and nd that the latter provide an upper limit on the lepton Yukawa couplings. A large enhancement of the Higgs di-photon rate can therefore only be obtained when the mass of the lightest charged lepton is close to the LEP limit. The relic density constraint suggests a co-annihilation scenario with a small mass di erence between the lightest charged and neutral leptons, which also weakens the LEP limit on the lightest charged lepton mass and allows for larger Higgs di-photon decay rates. Cross sections for direct detection of the dark matter candidate are calculated, and prospects for detecting the new particles at the LHC are discussed brie y.
Work at ANL is supported in part by the U.S. Department of Energy, Division of High Energy Physics, under grant num- ber DE-AC02-06CH11357, and at UIC under grant number DE-FG02-84ER40173. A. J. acknowledges support from the Subrahmanyan Chandrasekhar Memorial Fellowship.
Publisher StatementPost print version of article may differ from published version. The final publication is available at springerlink.com; DOI: 10.1007/JHEP12(2012)064