Liangliang Shang

Interpreting the 750 GeV diphoton excess by the singlet extension of the Manohar–Wise model

Abstract The evidence of a new scalar particle X from the 750 GeV diphoton excess, and the absence of any other signal of new physics at the LHC so far suggest the existence of new colored scalars, which may be moderately light and thus can induce sizable Xgg and Xγγ couplings without resorting to very strong interactions. Motivated by this speculation, we extend the Manohar–Wise model by adding one gauge singlet scalar field. The resulting theory then predicts one singlet dominated scalar ϕ as well as three kinds of color-octet scalars, which can mediate through loops the ϕgg and ϕγγ interactions. After fitting the model to the diphoton data at the LHC, we find that in reasonable parameter regions the excess can be explained at 1σ level by the process g g → ϕ → γ γ , and the best points predict the central value of the excess rate with χ min 2 = 2.32 , which corresponds to a p-value of 0.68. We also consider the constraints from various LHC Run I signals, and we conclude that, although these constraints are powerful in excluding the parameter space of the model, the best points are still experimentally allowed.

Pair production of a 125 GeV Higgs boson in MSSM and NMSSM at the ILC

A bstractIn this work we investigate the Higgs pair production in the MSSM and NMSSM at the photon-photon collision of the ILC. We consider various experimental constraints and scan over the parameter space of the MSSM and NMSSM. Then we calculate the cross section of Higgs pair production in the allowed parameter space and compare the results with the predictions in the SM. We find that the large enhancement of the cross section in the MSSM is mainly due to the contributions from the loops mediated by the stau, while in the NMSSM it is mainly due to the contributions from the top-squark loops. For light

Interpreting The 750 GeV Diphoton Excess Within Topflavor Seesaw Model

{m_{{{{{\widetilde{\tau}}}_1}}}}

Supersymmetry explanation of the Fermi Galactic Center excess and its test at LHC run II

and large μ tan β, the production rate can be enhanced by a factor of 18 in the MSSM (relative to the SM prediction). And for a large trilinear soft breaking parameter At and a moderately light top-squark, it can also be enhanced by a factor of 2 in the NMSSM. Moreover, we also calculate the χ2 values with the LHC Higgs data and display the results for the parameter space with χ2 better than the SM value.

Interpreting the 750 GeV diphoton excess in the Minimal Dilaton Model

Abstract We propose that the extension of the Standard Model by typical vector-like S U ( 2 ) L doublet fermions and non-singlet scalar field can account for the observed 750 GeV diphoton excess in experimentally allowed parameter space. Such an idea can be realized in a typical topflavor seesaw model where the new resonance X is identified as a CP-even or CP-odd scalar emerging from a certain bi-doublet Higgs field, and it can couple rather strongly to photons and gluons through mediators such as vector-like fermions, scalars as well as gauge bosons predicted by the model. Numerical analysis indicates that the model can predict the central value of the diphoton excess without contradicting any constraints from 8 TeV LHC. Among all the constraints, the tightest one comes from the Zγ channel with σ 8 TeV Z γ ≲ 3.6 fb , which requires σ 13 TeV γ γ ≲ 6 fb in most of the favored parameter space. Theoretical issues such as vacuum stability and Landau pole are also addressed.

Interpreting the galactic center gamma-ray excess in the NMSSM

We explore the explanation of the Fermi Galactic Center Excess (GCE) in the Next-to-Minimal Supersymmetric Standard Model. We systematically consider various experimental constraints including the Dark Matter (DM) relic density, DM direct detection results and indirect searches from dwarf galaxies. We find that, for DM with mass ranging from

Explanation of the ATLAS Z-peaked excess in the NMSSM

30 {\rm GeV}

Explaining the DAMPE data with scalar dark matter and gauged \(U(1)_{L_e-L_\mu }\) interaction

to

Natural NMSSM after LHC Run I and the Higgsino dominated dark matter scenario

40 {\rm GeV}

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

, the GCE can be explained by the annihilation