Catalogue Search | MBRL
Search Results Heading
Explore the vast range of titles available.
MBRLSearchResults
-
DisciplineDiscipline
-
Is Peer ReviewedIs Peer Reviewed
-
Item TypeItem Type
-
SubjectSubject
-
YearFrom:-To:
-
More FiltersMore FiltersSourceLanguage
Done
Filters
Reset
76
result(s) for
"Rzehak, H"
Sort by:
Higgs-boson masses and mixing matrices in the NMSSM: analysis of on-shell calculations
by
Weiglein, G.
,
Gröber, R.
,
Drechsel, P.
in
Astronomy
,
Astrophysics and Cosmology
,
Elementary Particles
2017
We analyze the Higgs-boson masses and mixing matrices in the NMSSM based on an on-shell (OS) renormalization of the gauge-boson and Higgs-boson masses and the parameters of the top/scalar top sector. We compare the implementation of the OS calculations in the codes NMSSMCALC and NMSSM-FeynHiggs up to
O
(
α
t
α
s
)
. We identify the sources of discrepancies at the one- and at the two-loop level. Finally we compare the OS and
DR
¯
evaluation as implemented in NMSSMCALC. The results are important ingredients for an estimate of the theoretical precision of Higgs-boson mass calculations in the NMSSM.
Journal Article
Higgs-mass predictions in the MSSM and beyond
2021
Predictions for the Higgs masses are a distinctive feature of supersymmetric extensions of the Standard Model, where they play a crucial role in constraining the parameter space. The discovery of a Higgs boson and the remarkably precise measurement of its mass at the LHC have spurred new efforts aimed at improving the accuracy of the theoretical predictions for the Higgs masses in supersymmetric models. The “Precision SUSY Higgs Mass Calculation Initiative” (KUTS) was launched in 2014 to provide a forum for discussions between the different groups involved in these efforts. This report aims to present a comprehensive overview of the current status of Higgs-mass calculations in supersymmetric models, to document the many advances that were achieved in recent years and were discussed during the KUTS meetings, and to outline the prospects for future improvements in these calculations.
Journal Article
Supersymmetric models in light of improved Higgs mass calculations
2019
We discuss the parameter spaces of supersymmetry (SUSY) scenarios taking into account the improved Higgs-mass prediction provided by FeynHiggs 2.14.1. Among other improvements, this prediction incorporates three-loop renormalization-group effects and two-loop threshold corrections, and can accommodate three separate mass scales: \\[m_q\\] (for squarks), \\[m_g\\,\\!\\] (for gluinos) and \\[m_ \\] (for electroweakinos). Furthermore, it contains an improved treatment of the \\[ DR\\] scalar top parameters avoiding problems with the conversion to on-shell parameters, that yields more accurate results for large SUSY-breaking scales. We first consider the CMSSM, in which the soft SUSY-breaking parameters \\[m_0\\] and \\[m_1/2\\] are universal at the GUT scale, and then sub-GUT models in which universality is imposed at some lower scale. In both cases, we consider the constraints from the Higgs-boson mass \\[M_h\\] in the bulk of the \\[(m_0, m_1/2)\\] plane and also along stop coannihilation strips where sparticle masses may extend into the multi-TeV range. We then consider the minimal anomaly-mediated SUSY-breaking scenario, in which large sparticle masses are generic. In all these scenarios the substantial improvements between the calculations of \\[M_h\\] in FeynHiggs 2.14.1 and FeynHiggs 2.10.0, which was used in an earlier study, change significantly the preferred portions of the models’ parameter spaces. Finally, we consider the pMSSM11, in which sparticle masses may be significantly smaller and we find only small changes in the preferred regions of parameter space.
Journal Article
Implications of improved Higgs mass calculations for supersymmetric models
by
Ellis, J.
,
Marrouche, J.
,
Weiglein, G.
in
Astronomy
,
Astrophysics and Cosmology
,
CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
2014
We discuss the allowed parameter spaces of supersymmetric scenarios in light of improved Higgs mass predictions provided by FeynHiggs 2.10.0. The Higgs mass predictions combine Feynman-diagrammatic results with a resummation of leading and subleading logarithmic corrections from the stop/top sector, which yield a significant improvement in the region of large stop masses. Scans in the pMSSM parameter space show that, for given values of the soft supersymmetry-breaking parameters, the new logarithmic contributions beyond the two-loop order implemented in FeynHiggs tend to give larger values of the light CP-even Higgs mass,
M
h
, in the region of large stop masses than previous predictions that were based on a fixed-order Feynman-diagrammatic result, though the differences are generally consistent with the previous estimates of theoretical uncertainties. We re-analyse the parameter spaces of the CMSSM, NUHM1 and NUHM2, taking into account also the constraints from CMS and LHCb measurements of
BR
(
B
s
→
μ
+
μ
-
)
and ATLAS searches for
/
E
T
events using 20/fb of LHC data at 8 TeV. Within the CMSSM, the Higgs mass constraint disfavours
tan
β
≲
10
, though not in the NUHM1 or NUHM2.
Journal Article
The SM-like Higgs Boson Mass in the CP-Violating High-Scale Next-to Minimal Supersymmetric Standard Model
2025
In this report, we present a reliable prediction of the SM-like Higgs boson mass within the CP-violating next-to-minimal supersymmetric extension of the SM (NMSSM). We use an effective field theory framework together with two possible matching approaches: the matching of the quartic Higgs coupling and the matching of the pole mass of the Higgs boson. We compare results obtained by both methods and compare our results with the literature. We discuss the CP-violating effects arising from complex phases. Furthermore, we discuss different sources of the theoretical uncertainties entering our calculation.
Journal Article
Higgs boson masses in the complex NMSSM at one-loop level
by
Gröber, R.
,
Walz, K.
,
Mühlleitner, M.
in
Bosons
,
Classical and Quantum Gravitation
,
CP violation
2012
A
bstract
The Next-to-Minimal Supersymmetric Extension of the Standard Model (NMSSM) with a Higgs sector containing five neutral and two charged Higgs bosons allows for a rich phenomenology. In addition, the plethora of parameters provides many sources of CP violation. In contrast to the Minimal Supersymmetric Extension, CP violation in the Higgs sector is already possible at tree-level. For a reliable understanding and interpretation of the experimental results of the Higgs boson search, and for a proper distinction of Higgs sectors provided by the Standard Model or possible extensions, the Higgs boson masses have to be known as precisely as possible including higher-order corrections. In this paper we calculate the one-loop corrections to the neutral Higgs boson masses in the complex NMSSM in a Feynman diagrammatic approach adopting a mixed renormalization scheme based on on-shell and
conditions. We study various scenarios where we allow for tree-level CP-violating phases in the Higgs sector and where we also study radiatively induced CP violation due to a non-vanishing phase of the trilinear coupling
A
t
in the stop sector. The effects on the Higgs boson phenomenology are found to be significant. We furthermore estimate the theoretical error due to unknown higher-order corrections by both varying the renormalization scheme of the top and bottom quark masses and by adopting different renormalization scales. The residual theoretical error can be estimated to about 10%.
Journal Article
The sfermion-mass spectrum of the MSSM at the one-loop level
2003
The sfermion-mass spectrum of the minimal supersymmetric standard model is investigated at the one-loop level. An on-shell scheme has been specified for renormalization of the basic breaking parameters of the sfermionic sector. Owing to SU(2)-invariance, the soft-breaking mass parameters of the left-chiral scalar fermions of each isospin doublet are identical. Thus, one of the sfermion masses of each doublet can be expressed in terms of the other masses and receives a mass shift at the one-loop level with respect to the lowest-order value, which can be of O(10 GeV). Both strong and electroweak contributions have been calculated for scalar quarks and leptons.
Journal Article
SUSY background to neutral MSSM Higgs boson searches
2012
Within the Minimal Supersymmetric Standard Model (MSSM) the production and decay of superpartners can give rise to backgrounds for Higgs boson searches. Here MSSM background processes to the vector boson fusion channel with the Higgs boson decaying into two tau leptons or two W-bosons are investigated, giving rise to dilepton plus missing transverse momentum signals of the Higgs boson. Starting from a scenario with relatively small masses of the supersymmetric (SUSY) particles, with concomitant large cross section of the background processes, one obtains a first conservative estimate of the background. Light chargino pair production plus two jets, lightest and next-to-lightest neutralino production plus two jets as well as slepton pair production plus two jets are identified as important contributions to the irreducible SUSY background. Light chargino and next-to-lightest neutralino production plus two jets and next-to-lightest neutralino pair production plus two jets give rise to reducible backgrounds, which can be larger than the irreducible ones in some scenarios. The relevant distributions are shown and additional cuts for MSSM background reduction are discussed. Extrapolation to larger squark masses is performed and shows that MSSM backgrounds are quite small for squark masses at the current exclusion limits.
Journal Article
SUSY background to neutral MSSM Higgs boson searches
2012
Within the Minimal Supersymmetric Standard Model (MSSM) the production and decay of superpartners can give rise to backgrounds for Higgs boson searches. Here MSSM background processes to the vector boson fusion channel with the Higgs boson decaying into two tau leptons or two W-bosons are investigated, giving rise to dilepton plus missing transverse momentum signals of the Higgs boson. Starting from a scenario with relatively small masses of the supersymmetric (SUSY) particles, with concomitant large cross section of the background processes, one obtains a first conservative estimate of the background. Light chargino pair production plus two jets, lightest and nextto-lightest neutralino production plus two jets as well as slepton pair production plus two jets are identified as important contributions to the irreducible SUSY background. Light chargino and next-to-lightest neutralino production plus two jets and next-to-lightest neutralino pair production plus two
Journal Article