62 research outputs found
NMSPEC: A Fortran code for the sparticle and Higgs masses in the NMSSM with GUT scale boundary conditions
NMSPEC is a Fortran code that computes the sparticle and Higgs masses, as
well as Higgs decay widths and couplings in the NMSSM, with soft SUSY breaking
terms specified at MGUT. Exceptions are the soft singlet mass m_s^2 and the
singlet self coupling kappa, that are both determined in terms of the other
parameters through the minimization equations of the Higgs potential. We
present a first analysis of the NMSSM parameter space with universal SUSY
breaking terms at MGUT -- except for m_s and A_kappa -- that passes present
experimental constraints on sparticle and Higgs masses. We discuss in some
detail a region in parameter space where a SM-like Higgs boson decays
dominantly into two CP odd singlet-like Higgs states.Comment: 21 pages, 3 figure
A 750 GeV Diphoton Signal from a Very Light Pseudoscalar in the NMSSM
The excess of events in the diphoton final state near 750 GeV observed by
ATLAS and CMS can be explained within the NMSSM near the R-symmetry limit. Both
scalars beyond the Standard Model Higgs boson have masses near 750 GeV, mix
strongly, and share sizeable production cross sections in association with
b-quarks as well as branching fractions into a pair of very light
pseudoscalars. Pseudoscalars with a mass of ~ 210 MeV decay into collimated
diphotons, whereas pseudoscalars with a mass of ~ 500-550 MeV can decay either
into collimated diphotons or into three pi^0 resulting in collimated photon
jets. Various such scenarios are discussed; the dominant constraints on the
latter scenario originate from bounds on radiative Upsilon decays, but they
allow for a signal cross section up to 6.7 fb times the acceptance for
collimated multiphotons to pass as a single photon.Comment: Major update, 21 pages, scenarios with M_A ~ 210 MeV and M_A ~ 550
MeV added, references and output files from NMSSMTools added, section and
figure on Delta_eta of diphotons added. To appear in JHE
The semi-constrained NMSSM satisfying bounds from the LHC, LUX and Planck
We study the parameter space of the semi-constrained NMSSM, compatible with
constraints on the Standard Model like Higgs mass and signal rates, constraints
from searches for squarks and gluinos, a dark matter relic density compatible
with bounds from WMAP/Planck, and direct detection cross sections compatible
with constraints from LUX. The remaining parameter space allows for a
fine-tuning as low as about 100, an additional lighter Higgs boson in the
60-120 GeV mass range detectable in the diphoton mode or in decays into a pair
of lighter CP-odd Higgs bosons, and dominantly singlino like dark matter with a
mass down to 1 GeV, but possibly a very small direct detection cross section.Comment: 19 pages, 13 Figure
NMHDECAY: A Fortran Code for the Higgs Masses, Couplings and Decay Widths in the NMSSM
The Fortran code NMHDECAY computes the masses, couplings and decay widths of
all Higgs bosons of the NMSSM in terms of its parameters at the electroweak
(SUSY breaking) scale: the Yukawa couplings lambda and kappa, the soft
trilinear terms A_lambda and A_kappa, and tan(beta) and mu_eff = lambda*.
The computation of the spectrum includes leading two loop terms, electroweak
corrections and propagator corrections. The computation of the decay widths is
carried out as in HDECAY, but (for the moment) without three body decays. Each
point in parameter space is checked against negative Higgs bosons searches at
LEP, including unconventional channels relevant for the NMSSM. One version of
the program uses generalized SLHA conventions for input and output.Comment: Typos corrected, references added, radiative corrections written out
explicitely in new appendix
Additional Higgs Bosons near 95 and 650 GeV in the NMSSM
Hints for an additional Higgs boson with a mass of about 95 GeV originate
from LEP and searches in the diphoton channel by CMS and ATLAS. A search for
resonant production of SM plus BSM Higgs bosons in the diphoton plus bb channel
by CMS showed some excess for a 650 GeV resonance decaying into the SM Higgs
plus a 95 GeV Higgs boson. We investigate whether these phenomena can be
interpreted simultaneously within the NMSSM subject to the latest constraints
on couplings of the SM Higgs boson, on extra Higgs bosons from the LHC, and on
dark matter direct detection cross sections.Comment: 14 pages, 12 Figure
, Dark Matter and in the NMSSM
We study regions in the parameter space of the NMSSM which are able to
simultaneously explain the current measured values for the mass and
the muon anomalous magnetic moment , and provide a dark matter relic
density consistent with the observations as well as constraints from detection
experiments. The corresponding regions feature light charginos, sleptons and
staus in the 100-800~GeV range, at least some of them with masses below 150~GeV
such that the electroweakly-interacting SUSY particles generate sufficiently
large contributions to . The LSP is always singlino-like with a mass below
140~GeV, and could possibly remain invisible even at future detection
experiments. Decays of electroweak sparticles proceed through cascades via
staus and/or sleptons which makes their detection challenging. We propose
benchmark points for future searches of such sparticles. The lightest CP-even
scalar may have a mass in the 95-98~GeV range with, however, modest signal
rates in view of the mild excesses reported in this range at LEP and by CMS at
the LHC.Comment: 8 pages, 6 figures, references added, figures improved, SLHA files of
bench mark points added as ancillary file
Gauge Mediation in the NMSSM with a Light Singlet: Sparticles within the Reach of LHC Run II
Relatively light stops in gauge mediation models are usually made compatible
with the Higgs mass of 125 GeV by introducing direct Higgs-messenger couplings.
We show that such couplings are not necessary in a simple and predictive model
that combines minimal gauge mediation and the next-to-minimal supersymmetric
standard model (NMSSM). We show that one can obtain a 125 GeV Standard
Model-like Higgs boson with stops as light as 1.1 TeV, thanks to the mixing of
the Higgs with a singlet state at GeV that can explain the
LEP excess. In this scenario the singlet-higgs-higgs superfields coupling
is small and large. Sparticle searches at the LHC may
come with additional jets or taus and may involve displaced vertices. The
sparticle production cross-section at the 13 TeV LHC can be fb, leading to great prospects for discovery in the early phase of
LHC Run II
Constraints from Charge and Colour Breaking Minima in the (M+1)SSM
We study the constraints on the parameter space of the supersymmetric
standard model extended by a gauge singlet, which arise from the absence of
global minima of the effective potential with slepton or squark vevs.
Particular attention is paid to the so-called ``UFB'' directions in field
space, which are F-flat in the MSSM. Although these directions are no longer
F-flat in the (M+1)SSM, we show that the corresponding MSSM-like constraints on
m_0/M_{1/2} apply also to the (M+1)SSM. The net effect of all constraints on
the parameter space are more dramatic than in the MSSM. We discuss the
phenomenological implications of these constraints.Comment: 18 pages (LaTeX2e), 1 fi
Radiative Upsilon decays and a light pseudoscalar Higgs in the NMSSM
We study possible effects of a light CP-odd Higgs boson on radiative Upsilon
decays in the Next-to-Minimal Supersymmetric Standard Model. Recent constraints
from CLEO on radiative Upsilon(1S) decays are translated into constraints on
the parameter space of CP-odd Higgs boson masses and couplings, and compared to
constraints from B physics and the muon anomalous magnetic moment. Possible
Higgs - eta_b(nS) mixing effects are discussed, notably in the light of the
recent measurement of the eta_b(1S) mass by Babar: The somewhat large
Upsilon(1S) - eta_b(1S) hyperfine splitting could easily be explained by the
presence of a CP-odd Higgs boson with a mass in the range 9.4 - 10.5 GeV. Then,
tests of lepton universality in inclusive radiative Upsilon decays can provide
a visible signal in forthcoming experimental data.Comment: 20 pages, 11 Figs, references correcte
Yukawa Induced Radiative Corrections to the Lightest Higgs Boson Mass in the NMSSM
We compute the leading logarithmic radiative corrections to the lightest
Higgs mass in the NMSSM involving the electroweak gauge couplings and in the
NMSSM specific Yukawa couplings lambda and kappa (including all mixed
combinations), which are induced by chargino, neutralino and Higgs boson loops.
The effect of the NMSSM specific Yukawa couplings lambda and kappa is to
increase the upper bound on the lightest Higgs mass by up to ~2 GeV, but they
can also decrease the lightest Higgs mass by up to ~-20 GeV.Comment: 12 pages, 3 figs, improved (generalized) treatment of CP odd loop
contributions; the possibility to get large negative contributions to the
lightest Higgs mass is clarified in a third figure; typos correcte
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