Scalar dark matter and standard model with four generations
Journal
Physical Review D - Particles, Fields, Gravitation and Cosmology
Journal Volume
82
Journal Issue
3
Date Issued
2010
Author(s)
Abstract
We consider a scalar dark-matter (DM) model, the SM4+D, consisting of the standard model with four generations (SM4) and a real gauge-singlet scalar called darkon, D, as the WIMP DM candidate. We explore constraints on the darkon sector of the SM4+D from WIMP DM direct-search experiments, including CDMS-II and CoGeNT, and from the decay of a B meson into a kaon plus missing energy. We find that a sizable portion of the darkon parameter space is still compatible with the experimental data. Since the darkon-Higgs interaction may give rise to considerable enhancement of the Higgs invisible decay mode, the existence of the darkon could lead to the weakening or evasion of some of the restrictions on the Higgs mass in the presence of fourth-generation quarks. In addition, it can affect the flavor-changing decays of these new heavy quarks into a lighter quark and the Higgs boson, as the Higgs may subsequently decay invisibly. Therefore, we also study these flavor-changing neutral transitions involving the darkon, as well as the corresponding top-quark decay t→cDD, some of which may be observable at the Tevatron or LHC and thus provide additional tests for the SM4+D. © 2010 The American Physical Society.
SDGs
Type
journal article