Volume 77, Number 5, March 2007
Article Number 51002
Number of page(s) 5
Section The Physics of Elementary Particles and Fields
Published online 19 February 2007
EPL, 77 (2007) 51002
DOI: 10.1209/0295-5075/77/51002

A seesaw mechanism in the Higgs sector

X. Calmet and J. F. Oliver

Service de Physique Théorique - CP 225, Boulevard du Triomphe, B-1050 Brussels, Belgium

received 30 November 2006; accepted in final form 7 January 2007; published March 2007
published online 19 February 2007

In this paper we revisit the seesaw Higgs mechanism. We show how a seesaw mechanism in a two Higgs doublets model can trigger the electroweak symmetry breaking if at least one of the eigenvalues of the squared-mass matrix is negative. We then consider two special cases of interest. In the decoupling scenario, there is only one scalar degree of freedom in the low-energy regime. In the degenerate scenario, all five degrees of freedom are in the low-energy regime and will lead to observables effects at the LHC. Furthermore, in that scenario, it is possible to impose a discrete symmetry between the doublets that makes the extra neutral degrees of freedom stable. These are thus viable dark-matter candidates. We find an interesting relation between the electroweak-symmetry-breaking mechanism and dark matter.

11.15.Ex - Spontaneous breaking of gauge symmetries.
12.60.Fr - Extensions of electroweak Higgs sector.
95.35.+d - Dark matter (stellar, interstellar, galactic, and cosmological).

© Europhysics Letters Association 2007