[Show abstract][Hide abstract] ABSTRACT: We describe the new developments in version 4 of the public computer code
HiggsBounds. HiggsBounds is a tool to test models with arbitrary Higgs sectors,
containing both neutral and charged Higgs bosons, against the published
exclusion bounds from Higgs searches at the LEP, Tevatron and LHC experiments.
From the model predictions for the Higgs masses, branching ratios, production
cross sections and total decay widths - which are specified by the user in the
input for the program - the code calculates the predicted signal rates for the
search channels considered in the experimental data. The signal rates are
compared to the expected and observed cross section limits from the Higgs
searches to determine whether a point in the model parameter space is excluded
at 95% confidence level. In this document we present a modification of the
HiggsBounds main algorithm that extends the exclusion test in order to ensure
that it provides useful results in the presence of one or more significant
excesses in the data, corresponding to potential Higgs signals. We also
describe a new method to test whether the limits from an experimental search
performed under certain model assumptions can be applied to a different
theoretical model. Further developments discussed here include a framework to
take into account theoretical uncertainties on the Higgs mass predictions, and
the possibility to obtain the $\chi^2$ likelihood of Higgs exclusion limits
from LEP. Extensions to the user subroutines from earlier versions of
HiggsBounds are described. The new features are demonstrated by additional
example programs.
European Physical Journal C 10/2013; 74(3). DOI:10.1140/epjc/s10052-013-2693-2 · 5.08 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We discuss Higgs boson decays in the CP-violating MSSM, and examine their
phenomenological impact using cross section limits from the LEP Higgs searches.
This includes a discussion of the full 1-loop results for the partial decay
widths of neutral Higgs bosons into lighter neutral Higgs bosons (h_a -> h_b
h_c) and of neutral Higgs bosons into fermions (h_a -> f fbar). In calculating
the genuine vertex corrections, we take into account the full spectrum of
supersymmetric particles and all complex phases of the supersymmetric
parameters. These genuine vertex corrections are supplemented with Higgs
propagator corrections incorporating the full one-loop and the dominant
two-loop contributions, and we illustrate a method of consistently treating
diagrams involving mixing with Goldstone and Z bosons. In particular, the
genuine vertex corrections to the process h_a -> h_b h_c are found to be very
large and, where this process is kinematically allowed, can have a significant
effect on the regions of the CPX benchmark scenario which can be excluded by
the results of the Higgs searches at LEP. However, there remains an unexcluded
region of CPX parameter space at a lightest neutral Higgs boson mass of ~45
GeV. In the analysis, we pay particular attention to the conversion between
parameters defined in different renormalisation schemes and are therefore able
to make a comparison to the results found using renormalisation group
improved/effective potential calculations.
European Physical Journal C 03/2011; 71(6). DOI:10.1140/epjc/s10052-011-1669-3 · 5.08 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: HiggsBounds 2.0.0 is a computer code which tests both neutral and charged
Higgs sectors of arbitrary models against the current exclusion bounds from the
Higgs searches at LEP and the Tevatron. As input, it requires a selection of
model predictions, such as Higgs masses, branching ratios, effective couplings
and total decay widths. HiggsBounds 2.0.0 then uses the expected and observed
topological cross section limits from the Higgs searches to determine whether a
given parameter scenario of a model is excluded at the 95% C.L. by those
searches. Version 2.0.0 represents a significant extension of the code since
its first release (1.0.0). It includes now 28/53 LEP/Tevatron Higgs search
analyses, compared to the 11/22 in the first release, of which many of the ones
from the Tevatron are replaced by updates. As a major extension, the code
allows now the predictions for (singly) charged Higgs bosons to be confronted
with LEP and Tevatron searches. Furthermore, the newly included analyses
contain LEP searches for neutral Higgs bosons (H) decaying invisibly or into
(non flavour tagged) hadrons as well as decay-mode independent searches for
neutral Higgs bosons, LEP searches via the production modes tau+ tau- H and b
b-bar H, and Tevatron searches via t t-bar H. Also, all Tevatron results
presented at the ICHEP'10 are included in version 2.0.0. As physics
applications of HiggsBounds 2.0.0 we study the allowed Higgs mass range for
model scenarios with invisible Higgs decays and we obtain exclusion results for
the scalar sector of the Randall-Sundrum model using up-to-date LEP and
Tevatron direct search results.
[Show abstract][Hide abstract] ABSTRACT: We introduce version 2.0.0 of the computer program HiggsBounds. The program
tests neutral and charged Higgs sectors of new models against the current
exclusion bounds from LEP and the Tevatron. As input, it requires a selection
of model predictions, such as Higgs masses, branching ratios, effective
couplings and total decay widths. The program then uses the expected and
observed topological cross section limits from the Higgs searches to determine
whether a given parameter scenario of a model is excluded at the 95% C.L. by
those searches. Version 2.0.0 includes 39/53 LEP/Tevatron Higgs search
analyses, compared to 13/36 in the previous release (1.2.0). Among the newly
included analyses are LEP searches for neutral Higgs bosons (H) decaying
invisibly or into hadrons, LEP searches via the production modes (tau+ tau- H)
and (b b-bar H), Tevatron searches via (t t-bar H), and LEP and Tevatron
searches for charged Higgs bosons. Also, all Tevatron results presented at the
ICHEP'10 are included in version 2.0.0. In this talk, we explain the basic
ideas behind the implementation of HiggsBounds and provide a list of search
topologies implemented in version 2.0.0. Furthermore, we apply HiggsBounds
2.0.0 to (a) determine the allowed Higgs mass range for a simple 4th generation
model, (b) update/reproduce LEP/Tevatron Higgs exclusion plots for the MSSM
m_h-max benchmark scenario, and (c) show exclusion results for the scalar
sector of the Randall-Sundrum model.