1207.4235v2.pdf (1.25 MB)
Download fileDark Matter and enhanced h -> gamma gamma rate from vector-like Leptons
journal contribution
posted on 2013-12-13, 00:00 authored by Aniket Joglekar, Pedro Schwaller, Carlos E. M. WagnerIn 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.