16 research outputs found
Electroweak baryogenesis in the Z3-invariant NMSSM
We calculate the baryon asymmetry of the Universe in the Z3-invariant
Next-to-Minimal Supersymmetric Standard Model where the interactions of the
singlino provide the necessary source of charge and parity violation. Using the
closed time path formalism, we derive and solve transport equations for the
cases where the singlet acquires a vacuum expectation value (VEV) before and
during the electroweak phase transition. We perform a detailed scan to show how
the baryon asymmetry varies throughout the relevant parameter space. Our
results show that the case where the singlet acquires a VEV during the
electroweak phase transition typically generates a larger baryon asymmetry,
although we expect that the case where the singlet acquires a VEV first is far
more common for any model in which parameters unify at a high scale. Finally,
we examine the dependence of the baryon asymmetry on the three-body
interactions involving gauge singlets.Comment: 24 pages, version submitted to the journa
Higgs Boson Mass Predictions in SUGRA Unification, Recent LHC-7 Results, and Dark Matter
LHC-7 has narrowed down the mass range of the light Higgs boson. This result
is consistent with the supergravity unification framework, and the current
Higgs boson mass window implies a rather significant loop correction to the
tree value pointing to a relatively heavy scalar sparticle spectrum with
universal boundary conditions. It is shown that the largest value of the Higgs
boson mass is obtained on the Hyperbolic Branch of radiative breaking. The
implications of light Higgs boson in the broader mass range of 115 GeV to 131
GeV and a narrower range of 123 GeV to 127 GeV are explored in the context of
the discovery of supersymmetry at LHC-7 and for the observation of dark matter
in direct detection experiments.Comment: 8 pages, 5 figure
Excess Observed in CDF and SUSY at the LHC
The recent excess observed by CDF in is
interpreted in terms of a possible supersymmetric origin. An analysis is given
of the parameter space of mSUGRA and non-universal SUGRA models under the
combined constraints from LHC-7 with 165 pb of integrated luminosity,
under the new XENON-100 limits on the neutralino-proton spin independent cross
section and under the CDF 90% C.L. limit reported
to arise from an excess number of dimuon events. It is found that the predicted
value of the branching ratio consistent with all
the constraints contains the following set of NLSPs: chargino, stau, stop or CP
odd (even) Higgs. The lower bounds of sparticles, including those from the LHC,
XENON and CDF constraint, are exhibited and the shift in
the allowed range of sparticle masses arising solely due to the extra
constraint from the CDF result is given. It is pointed out that the two sided
CDF 90% C.L. limit puts upper bounds on sparticle masses. An analysis of
possible signatures for early discovery at the LHC is carried out corresponding
to the signal region in . Implications of GUT-scale
non-universalities in the gaugino and Higgs sectors are discussed. If the
excess seen by the CDF Collaboration is supported by further data from LHCb or
D0, this new result could be a harbinger for the discovery of supersymmetry.Comment: References added, text update
Naturalness, Supersymmetry and Implications for LHC and Dark Matter
It is shown that the Hyperbolic Branch of the radiative electroweak symmetry
breaking contains in it three regions: the Focal Point, Focal Curves, and Focal
Surfaces. Further, the Focal Point is shown to lie on the boundary of a Focal
Curve. These focal regions allow for a small while scalar masses can
become large and may lie in the several TeV region. It is shown that for the
mSUGRA model the current LHC-7 constraint depletes the Focal Point region while
regions on Focal Curves and Focal Surfaces remain largely intact. The LHC
implications for models which lie on Focal Curves are briefly discussed as well
as the implications of dark matter constraints for the Focal Point, Focal
Curves and Focal Surfaces are discussed.Comment: 10 pages, 8 figure
Implications of the Higgs Boson Discovery for mSUGRA
A Bayesian analysis is carried out to identify the consistent regions of the
mSUGRA parameter space, where the newly-discovered Higgs boson's mass is used
as a constraint, along with other experimental constraints. It is found that
can lie in the sub-TeV region, is mostly confined to a
narrow strip with , while is typically a TeV or larger.
Further, the Bayesian analysis is used to set 95% CL lower bounds on sparticle
masses. Additionally, it is shown that the spin independent neutralino-proton
cross section lies just beyond the reach of the current sensitivity but within
the projected sensitivity of the SuperCDMS-1T and XENON-1T experiments, which
explains why dark matter has thus far not been detected. The light sparticle
spectrum relevant for the discovery of supersymmetry at the LHC are seen to be
the gluino, the chargino and the stop with the gluino and the chargino as the
most likely candidates.Comment: Corrections included to reflect journal versio
Interpreting the First CMS and ATLAS SUSY Results
The CMS and the ATLAS Collaborations have recently reported on the search for
supersymmetry with 35 pb of data and have put independent limits on the
parameter space of the supergravity unified model with universal boundary
conditions at the GUT scale for soft breaking, i.e., the mSUGRA model. We
extend this study by examining other regions of the mSUGRA parameter space in
and . Further, we contrast the reach of CMS and ATLAS with 35
pb of data with the indirect constraints, i.e., the constraints from the
Higgs boson mass limits, from flavor physics and from the dark matter limits
from WMAP. Specifically it is found that a significant part of the parameter
space excluded by CMS and ATLAS is essentially already excluded by the indirect
constraints and the fertile region of parameter space has yet to be explored.
We also emphasize that gluino masses as low as 400 GeV but for squark masses
much larger than the gluino mass remain unconstrained and further that much of
the hyperbolic branch of radiative electroweak symmetry breaking, with low
values of the Higgs mixing parameter , is essentially untouched by the
recent LHC analysis.Comment: 3 figure panels, 10 plot
Sparticle mass hierarchies, simplified models from SUGRA unification, and benchmarks for LHC Run-II SUSY searches
Sparticle mass hierarchies contain significant information regarding the
origin and nature of supersymmetry breaking. The hierarchical patterns are
severely constrained by electroweak symmetry breaking as well as by the
astrophysical and particle physics data. They are further constrained by the
Higgs boson mass measurement. The sparticle mass hierarchies can be used to
generate simplified models consistent with the high scale models. In this work
we consider supergravity models with universal boundary conditions for soft
parameters at the unification scale as well as supergravity models with
nonuniversalities and delineate the list of sparticle mass hierarchies for the
five lightest sparticles. Simplified models can be obtained by a truncation of
these, retaining a smaller set of lightest particles. The mass hierarchies and
their truncated versions enlarge significantly the list of simplified models
currently being used in the literature. Benchmarks for a variety of
supergravity unified models appropriate for SUSY searches at future colliders
are also presented. The signature analysis of two benchmark models has been
carried out and a discussion of the searches needed for their discovery at LHC
RUN-II is given. An analysis of the spin independent neutralino-proton cross
section exhibiting the Higgs boson mass dependence and the hierarchical
patterns is also carried out. It is seen that a knowledge of the spin
independent neutralino-proton cross section and the neutralino mass will narrow
down the list of the allowed sparticle mass hierarchies. Thus dark matter
experiments along with analyses for the LHC Run-II will provide strong clues to
the nature of symmetry breaking at the unification scale.Comment: To appear in JHEP; 37 pages, 11 tables, 11 figure
