HE Seminar Michel Herquet
Speaker:Michel Herquet
Host:J. Gunion
Title: Twisted Higgs phenomenology at hadron colliders"
Abstract: In the Standard Model for electroweak interactions, the Higgs sector is known to display a
custodial symmetry protecting the mass relation mW+- = mW3 from large corrections. When
considering extensions of the scalar sector, like the two-Higgs-doublet model, one could
introducethis global symmetryby hand in order to pass current electroweak precision tests
in a natural way.
Assuming the invariance of the potential under CP transformations, the existence of a second
custodial
scenario characterized by mH+- =~ mH0 instead of mH+- =~ mA0 can be proved [1].
The phenomenology associated with such a model is potentially interesting. For example, a
light
pseudoscalar (mA0 =~ 30 GeV) together with an heavy SM-like Higgs boson (mh0 =~ 300 GeV)
could perfectly survive all direct and indirect constraints. Such a scenario could lead to
unexpected signatures at hadron colliders, like an unusual top decay t>W+bbb via the charged
Higgs decay H+>W+A0, scalar decays of the SM-like Higgs
h0>A0A0,H+H,H0H0characterized,for example,
by the exotic ZZbbbb final state(gg>h0>H0H0>ZA0ZA0> ZZbbbb), ...
In this talk I will expose the definition of a twisted custodialsymmetry in a 2HDM and then
review
the phenomenology of this model. After summarizing alldirect and indirect constraints, I
will detail
the possible collidersignatures at Tevatron and LHCand some preliminary results [2]
obtained
using MadGraph v4 and the generic 2HDM implementation[3].
[1]J. M. Grard, M. Herquet,Phys. Rev. Lett. 98 : 251802 (2007)
[2] S. de Visscher, J. M. Grard, M. Herquet, V. Lematre, and F. Maltoni (2007), in
preparation
[3]Johan Alwall, Pavel Demin, Simon de Visscher, Rikkert Frederix, Michel Herquet, Fabio Maltoni, Tilman Plehn, David L. Rainwater, and Tim Stelzer,JHEP 09 : 028 (2007)