6 research outputs found
Consistency of the Two Higgs Doublet Model and CP violation in top production at the LHC
It is important to provide guidance on whether CP violation may be measurable
in top-quark production at the Large Hadron Collider. The present work extends
an earlier analysis of the non-supersymmetric Two-Higgs-Doublet Model in this
respect, by allowing a more general potential. Also, a more comprehensive study
of theoretical and experimental constraints on the model is presented. Vacuum
stability, unitarity, direct searches and electroweak precision measurements
severely constrain the model. We explore, at low \tan\beta, the allowed regions
in the multidimensional parameter space that give a viable physical model. This
exploration is focused on the parameter space of the neutral sector rotation
matrix, which is closely related to the Yukawa couplings of interest. In most
of the remaining allowed regions, the model violates CP. We present a
quantitative discussion of a particular CP-violating observable. This would be
measurable in semileptonically decaying top and antitop quarks produced at the
LHC, provided the number of available events is of the order of a million.Comment: 45 pages, 10 figures, some in (essential) colour. Figures 2, 6 and 7
are bitmapped, better quality available on request. Version to appear in
Nucl. Phys.
Constraining the Two-Higgs-Doublet-Model parameter space
We confront the Two-Higgs-Doublet Model with a variety of experimental
constraints as well as theoretical consistency conditions. The most
constraining data are the \bar B\to X_s\gamma decay rate (at low values of
M_{H^\pm}), and \Delta\rho (at both low and high M_{H^\pm}). We also take into
account the B\bar B oscillation rate and R_b, or the width \Gamma(Z\to b\bar b)
(both of which restrict the model at low values of \tan\beta), and the
B^-\to\tau\nu_\tau decay rate, which restricts the model at high \tan\beta and
low M_{H^\pm}. Furthermore, the LEP2 non-discovery of a light, neutral Higgs
boson is considered, as well as the muon anomalous magnetic moment. Since
perturbative unitarity excludes high values of \tan\beta, the model turns out
to be very constrained. We outline the remaining allowed regions in the
\tan\beta-M_{H^\pm} plane for different values of the masses of the two
lightest neutral Higgs bosons, and describe some of their properties.Comment: 17 pages, 17 figure