177 research outputs found
Higgs pair production with SUSY QCD correction: revisited under current experimental constraints
We consider the current experimental constraints on the parameter space of
the MSSM and NMSSM. Then in the allowed parameter space we examine the Higgs
pair production at the 14 TeV LHC via ( is the 125 GeV
SM-like Higg boson) with one-loop SUSY QCD correction and compare it with the
production via . We obtain the following observations: (i) For the
MSSM the production rate of can reach 50 fb and thus can be
competitive with , while for the NMSSM has a much
smaller rate than due to the suppression of the
coupling; (ii) The SUSY-QCD correction to is sizable, which
can reach for the MSSM and for the NMSSM within the
region of the Higgs data; (iii) In the heavy SUSY limit (all soft mass
parameters become heavy), the SUSY effects decouple rather slowly from the
Higgs pair production (especially the process), which, for TeV and TeV, can enhance the production rate by a factor of
1.5 and 1.3 for the MSSM and NMSSM, respectively. So, the Higgs pair production
may be helpful for unraveling the effects of heavy SUSY.Comment: discussions and references added, accepted by JHE
A light Higgs scalar in the NMSSM confronted with the latest LHC Higgs data
In the Next-to-Minimal Supersymemtric Standard Model (NMSSM), one of the
neutral Higgs scalars (CP-even or CP-odd) may be lighter than half of the
SM-like Higgs boson. In this case, the SM-like Higgs boson h can decay into
such a light scalar pair and consequently the diphoton and ZZ signal rates at
the LHC will be suppressed. In this work, we examine the constraints of the
latest LHC Higgs data on such a possibility. We perform a comprehensive scan
over the parameter space of the NMSSM by considering various experimental
constraints and find that the LHC Higgs data can readily constrain the
parameter space and the properties of the light scalar, e.g., at 3
level this light scalar should be highly singlet dominant and the branching
ratio of the SM-like Higgs boson decay into the scalar pair should be less than
about 30%. Also we investigate the detection of this scalar at various
colliders. Through a detailed Monte Carlo simulation we find that under the
constraints of the current Higgs data this light scalar can be accessible at
the LHC-14 with an integrated luminosity over 300 fb.Comment: Accepted by JHE
A scalar potential from gauge condensation and its implications
We consider a scalar field whose coupling to the kinetic term of a
non-abelian gauge field is set at an UV scale . Then the confinement of the
gauge sector will induce a -dependent vacuum energy which generates a
dimensionful potential for the scalar. It provides a good example of dynamical
generation of a new physics scale below through the vacuum expectation
value . This mechanism may shed light on the origin of
dark matter, or spontaneous symmetry breaking applicable to the electroweak
symmetry.Comment: 4 pages, 3 figure
A light SUSY dark matter after CDMS-II, LUX and LHC Higgs data
In SUSY, a light dark matter is usually accompanied by light scalars to
achieve the correct relic density, which opens new decay channels of the SM
like Higgs boson. Under current experimental constraints including the latest
LHC Higgs data and the dark matter relic density, we examine the status of a
light neutralino dark matter in the framework of NMSSM and confront it with the
direct detection results of CoGeNT, CDMS-II and LUX. We have the following
observations: (i) A dark matter as light as 8 GeV is still allowed and its
scattering cross section off the nucleon can be large enough to explain the
CoGeNT/CDMS-II favored region; (ii) The LUX data can exclude a sizable part of
the allowed parameter space, but still leaves a light dark matter viable; (iii)
The SM-like Higgs boson can decay into the light dark matter pair with an
invisible branching ratio reaching 30% under the current LHC Higgs data, which
may be tested at the 14 TeV LHC experiment.Comment: 18 pages, 4 figure
Two-Higgs-doublet model with a color-triplet scalar: a joint explanation for top quark forward-backward asymmetry and Higgs decay to diphoton
The excess of top quark forward-backward asymmetry () reported by
the Tevatron and the enhancement of the Higgs decay to diphoton observed by the
LHC may point to a same origin of new physics. In this note we examined such
anomalies in the two-Higgs-doublet model with a color-triplet scalar. We found
that under current experimental constraints this model can simultaneously
explain both anomalies at level. Also, we examined the Higgs decay
and displayed its correlation with . We found
that unlike other models, this model predicts a special correlation between
and , i.e., the rate is highly
suppressed while the rate is enhanced. This behavior may help to
distinguish this model in the future high luminosity run of the LHC.Comment: 18pages, 4figures, references adde
A minimal extension of MSSM in light of the B decay anomaly
Motivated by the and anomalies from B decays, we extend the
minimal supersymmetric model with a non-universal anomaly-free
gauge symmetry, coupling non-universally to the lepton sector as well as the
quark sector. In particular, only the third generation quarks are charged under
this , which can easily evade the dilepton bound from the LHC
searches. An extra singlet is introduced to break this symmetry
allowing for the -term to be generated dynamically. The relevant
constraints of mixing, mixing and the LHC
dilepton searches are considered. We find that in the allowed parameter space
this gauge interaction can accommodate the and
anomalies and weaken considerably the mass limits while remaining
perturbative up to the Planck scale.Comment: 12 pages,2 figure
Vacuum stability in stau-neutralino coannihilation in MSSM
The stau-neutralino coannihilation provides a feasible way to accommodate the
observed cosmological dark matter (DM) relic density in the minimal
supersymmetric standard model (MSSM). In such a coannihilation mechanism the
stau mass usually has an upper bound since its annihilation rate becomes small
with the increase of DM mass. Inspired by this observation, we examine the
upper limit of stau mass in the parameter space with a large mixing of staus.
We find that the stau pair may dominantly annihilate into dibosons and hence
the upper bound on the stau mass ( GeV) obtained from the
final states can be relaxed. Imposing the DM relic density constraint and
requiring a long lifetime of the present vacuum, we find that the lighter stau
mass can be as heavy as about 1.4 TeV for the stau maximum mixing. However, if
requiring the present vacuum to survive during the thermal history of the
universe, this mass limit will reduce to about 0.9 TeV. We also discuss the
complementarity of vacuum stability and direct detections in probing this stau
coannihilation scenario.Comment: 12 pages, 6 figure
- …