Precise predictions for the Higgs-boson masses in the NMSSM
Eur. Phys. J. C
Precise predictions for the Higgs-boson masses in the NMSSM
P. Drechsel 2
L. Galeta 1
S. Heinemeyer 0 1
G. Weiglein 2
0 Instituto de Física Teórica, (UAM/CSIC), Universidad Autónoma de Madrid , Cantoblanco, 28049 Madrid , Spain
1 Instituto de Física de Cantabria (CSIC-UC) , Santander , Spain
2 DESY , Notkestraß e 85, 22607 Hamburg , Germany
The particle discovered in the Higgs-boson searches at the LHC with a mass of about 125 GeV can be identified with one of the neutral Higgs bosons of the Nextto-Minimal Supersymmetric Standard Model (NMSSM). We calculate predictions for the Higgs-boson masses in the NMSSM using the Feynman-diagrammatic approach. The predictions are based on the full NMSSM one-loop corrections supplemented with the dominant and sub-dominant two-loop corrections within the Minimal Supersymmetric Standard Model (MSSM). These include contributions at O(αt αs , αbαs , αt2, αt αb), as well as a resummation of leading and subleading logarithms from the top/scalar top sector. Taking these corrections into account in the prediction for the mass of the Higgs boson in the NMSSM that is identified with the observed signal is crucial in order to reach a precision at a similar level as in the MSSM. The quality of the approximation made at the two-loop level is analysed on the basis of the full one-loop result, with a particular focus on the prediction for the Standard Model-like Higgs boson that is associated with the observed signal. The obtained results will be used as a basis for the extension of the code FeynHiggs to the NMSSM.
1 Introduction
The spectacular discovery of a boson with a mass around
125 GeV by the ATLAS and CMS experiments [
1,2
] at
CERN constitutes a milestone in the quest for understanding
the physics of electroweak symmetry breaking. Any model
describing electroweak physics needs to provide a state that
can be identified with the observed signal. While within
the present experimental uncertainties the properties of the
observed state are compatible with the predictions of the
Standard Model (SM) [
3,4
], many other interpretations are
possible as well, in particular as a Higgs boson of an extended
Higgs sector.
One of the prime candidates for physics beyond the SM is
supersymmetry (SUSY), which doubles the particle degrees
of freedom by predicting two scalar partners for all SM
fermions, as well as fermionic partners to all bosons. The
most widely studied SUSY framework is the Minimal
Supersymmetric Standard Model (MSSM) [
5,6
], which keeps the
number of new fields and couplings to a minimum. In
contrast to the single Higgs doublet of the (minimal) SM, the
Higgs sector of the MSSM contains two Higgs doublets,
which in the CP conserving case leads to a physical spectrum
consisting of two CP-even, one CP-odd and two charged
Higgs bosons. The light CP-even MSSM Higgs boson can
be interpreted as the signal discovered at about 125 GeV; see
e.g. [
7,8
].
Going beyond the MSSM, this model has a well-motivated
extension in the Next-to-Minimal Supersymmetric Standard
Model (NMSSM); see e.g. [
9,10
] for reviews. The NMSSM
provides in particular a solution for naturally associating an
adequate scale to the μ parameter appearing in the MSSM
superpotential [
11,12
]. In the NMSSM, the introduction of a
new singlet superfield, which only couples to the Higgs and
sfermion sectors, gives rise to an effective μ-term,
generated in a similar way as the Yukawa mass terms of fermions
through its vacuum expectation value. In the case where
CP is conserved, which we assume throughout the paper,
the states in the NMSSM Higgs sector can be classified as
three CP-even Higgs bosons, hi (i = 1, 2, 3), two CP-odd
Higgs bosons, A j ( j = 1, 2), and the charged Higgs-boson
pair H ±. In addition, the SUSY partner of the singlet Higgs
(called the singlino) extends the neutralino sector to a total of
five neutralinos. In the NMSSM the lightest but also the
second lightest CP-even neutral Higgs boson can be interpreted
as the signal observed at about 125 GeV; see, e.g., [
13,14
].
The measured mass value of the observed signal has
already reached the level of a precision observable, with an
experimental accuracy of better than 300 MeV [
15
], and by
itself provides an important test for the predictions of models
of electroweak symmetry breaking. In the MSSM the masses
of the CP-even Higgs bosons can be predicted at lowest order
in terms of two SUSY parameters characterising the MSSM
Higgs sector, e.g. tan β, the ratio of the vacuum
expectation values of the two doublets, and the mass of the CP-odd
Higgs boson, MA, or the charged Higgs boson, MH± . These
relations, which in particular give rise to an upper bound
on the mass of the light CP-even Higgs boson given by the
Z -boson mass, receive large corrections from higher-order
contributions. In the NMSSM the corresponding predictions
are modified both at the tree level and the loop level. In order
to fully exploit th (...truncated)