Chengcheng Han

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.

Constraining top partner and naturalness at the LHC and TLEP

Abstract We investigate indirect constraints on the top partner within the minimal fermionic top partner model. By performing a global fit of the latest Higgs data, B s → μ + μ − measurements and the electroweak precision observables we find that the top partner with the mass up to 830 GeV is excluded at 2σ level. Our bound on the top partner mass is much stronger than the bounds obtained from the direct searches at the LHC. Under the current constraints the fine-tuning measure is less than 9% and the branching ratio of T → t Z is bounded between 14% and 25%. We also find that precise measurements of Higgs couplings at 240 GeV TLEP will constrain the top partner mass in multi-TeV region.

Top-squark in natural SUSY under current LHC run-2 data

We utilize the recent LHC-13 TeV data to study the lower mass bound on the top-squark (stop) in natural supersymmetry. We recast the LHC sparticle inclusive search of 1) with

Flavoured B − L local symmetry and anomalous rare B decays

\alpha _T

LHC search for right-handed neutrinos in Z′ models

αT variable, the direct stop pair search (1-lepton channel and all-hadronic channel) and the monojet analyses. We find that these searches are complementary depending on stop and higgsino masses: for a heavy stop the all-hadronic stop pair search provides the strongest bound, for an intermediate stop the inclusive SUSY analysis with

KK graviton resonance and cascade decays in warped gravity

\alpha _T