31 research outputs found

### A 125 GeV Higgs and its di-photon signal in different SUSY models: a mini review

In this note we briefly review our recent studies on a 125 GeV Higgs and its
di-photon signal rate in different low energy supersymmetric models, namely the
minimal supersymmetric standard model (MSSM), the next-to-minimal
supersymmetric standard model (NMSSM), the nearly minimal supersymmetric
standard model (nMSSM) and the constrained MSSM. Our conclusion is: (i) In the
allowed parameter space the SM-like Higgs boson can easily be 125 GeV in the
MSSM, NMSSM and nMSSM, while it is hard to realize in the constrained MSSM;
(ii) The di-photon Higgs signal rate in the nMSSM and constrained MSSM is
suppressed relative to the prediction of the SM, while the signal rate can be
enhanced in the MSSM and NMSSM; (iii) The NMSSM may allow for a lighter
top-squark than the MSSM, which can thus ameliorate the fine-tuning problem.Comment: 16 pages, 8 figures,version in Advances in High Energy Physic

### Top quark forward-backward asymmetry at the Tevatron: a comparative study in different new physics models

The top quark forward-backward asymmetry A_{FB}^t measured at the Tevatron is
above the Standard Model prediction by more than 2-sigma deviation, which might
be a harbinger for new physics. In this work we examine the contribution to
A_{FB}^t in two different new physics models: one is the minimal supersymmetric
model without R-parity (RPV-MSSM) which contributes to A_{FB}^t via
sparticle-mediated t-channel process d d_bar-> t t_bar; the other is the
third-generation enhanced left-right model (LR model) which contributes to
A_{FB}^t via Z'-mediated t-channel or s-channel processes. We find that in the
parameter space allowed by the tt_bar production rate and the tt_bar invariant
mass distribution at the Tevatron, the LR model can enhance A_{FB}^t to within
the 2-sigma region of the Tevatron data for the major part of the parameter
space, and in optimal case A_{FB}^t can reach 12% which is slightly below the
1-sigma lower bound. For the RPV-MSSM, only in a narrow part of the parameter
space can the \lambda'' couplings enhance A_{FB}^t to within the 2-sigma region
while the \lambda' couplings just produce negative contributions to worsen the
fit.Comment: Version in PRD (RPV-MSSM lambda" effects added

### Pair production of 125 GeV Higgs boson in the SM extension with color-octet scalars at the LHC

Although the Higgs boson mass and single production rate have been determined
more or less precisely, its other properties may deviate significantly from its
predictions in the standard model (SM) due to the uncertainty of Higgs data. In
this work we study the Higgs pair production at the LHC in the Manohar-Wise
model, which extends the SM by one family of color-octet and isospin-doublet
scalars. We first scanned over the parameter space of the Manohar-Wise model
considering exprimental constraints and performed fits in the model to the
latest Higgs data by using the ATLAS and CMS data separately. Then we
calculated the Higgs pair production rate and investigated the potential of its
discovery at the LHC14. We conclude that: (i) Under current constrains
including Higgs data after Run I of the LHC, the cross section of Higgs pair
production in the Manohar-Wise model can be enhanced up to even $10^3$ times
prediction in the SM. (ii) Moreover, the sizable enhancement comes from the
contributions of the CP-odd color-octet scalar $S^A_I$. For lighter scalar
$S^A_I$ and larger values of $|\lambda_I|$, the cross section of Higgs pair
production can be much larger. (iii) After running again of LHC at 14 TeV, most
of the parameter spaces in the Manohar-Wise model can be test. For an
integrated luminosity of 100 fb$^{-1}$ at the LHC14, when the normalized ratio
$R=10$, the process of Higgs pair production can be detected.Comment: 13 pages, 4 figure

### Pair Production of a 125 GeV Higgs Boson in MSSM and NMSSM at the LHC

In light of the recent LHC Higgs search data, we investigate the pair
production of a SM-like Higgs boson around 125 GeV in the MSSM and NMSSM. We
first scan the parameter space of each model by considering various
experimental constraints, and then calculate the Higgs pair production rate in
the allowed parameter space. We find that in most cases the dominant
contribution to the Higgs pair production comes from the gluon fusion process
and the production rate can be greatly enhanced, maximally 10 times larger than
the SM prediction (even for a TeV-scale stop the production rate can still be
enhanced by a factor of 1.3). We also calculate the chi-square value with the
current Higgs data and find that in the most favored parameter region the
production rate is enhanced by a factor of 1.45 in the MSSM, while in the NMSSM
the production rate can be enhanced or suppressed (\sigma_{SUSY}/\sigma_{SM}
varies from 0.7 to 2.4).Comment: 15 pages, 5 figure

### Properties of Heavy Higgs Bosons and Dark Matter under Current Experimental Limits in the $\mu$NMSSM

Searches for new particles beyond the Standard Model (SM) are an important
task for the Large Hadron Collider (LHC). In this paper, we investigate the
properties of the heavy non-SM Higgs bosons in the $\mu$-term extended
Next-to-Minimal Supersymmetric Standard Model ($\mu$NMSSM). We scan the
parameter space of the $\mu$NMSSM considering the basic constraints from Higgs
data, dark matter (DM) relic density, and LHC searches for sparticles. And we
also consider the constraints from the LZ2022 experiment and the muon anomaly
constraint at 2$\sigma$ level.
We find that the LZ2022 experiment has a strict constraint on the parameter
space of the $\mu$NMSSM, and the limits from the DM-nucleon spin-independent
(SI) and spin-dependent (SD) cross-sections are complementary. Then we discuss
the exotic decay modes of heavy Higgs bosons decaying into SM-like Higgs boson.
We find that for doublet-dominated Higgs $h_3$ and $A_2$, the main exotic decay
channels are $h_3\rightarrow Z A_1$, $h_3\rightarrow h_1 h_2$, $A_2\rightarrow
A_1 h_1$ and $A_2\rightarrow Z h_2$, and the branching ratio can reach to about
23$\%$, 10$\%$, 35$\%$ and 10$\%$ respectively. At the 13 TeV LHC, the
production cross-section of $ggF\rightarrow h_3\rightarrow h_1 h_2$ and
$ggF\rightarrow A_2\rightarrow A_1 h_1$ can reach to about $10^{-11}$pb and
$10^{-10}$pb, respectively