We examine the effects of mixing induced light heavy charged lepton neutral currents on the partial wave amplitude for the process l⁺l⁻ →ZZ (withl = e,μ or τ). By imposing the constraints that the amplitude should not exceed the perturbative unitarity limit at high energy (√s = Λ), we obtain bounds on light heavy charged lepton mixing parameter sin²(2θ_L^a) where θ_L^a is the mixing angle of the ordinary charged lepton with its exotic partner. For Λ = 1 TeV, no bound is obtained on sin² (2θ_L^a) form_E < 0.69 TeV. However, sin² (2θ_L^a) ≤ 1.52×10⁻⁵ form_E = 5 TeV, sin² (2θ_L^a) ≤ 2.41 ×10⁻⁷ form_E = 10 TeV. Similarity for Λ = ∞ no bound is obtained on sin² (2θ_L^a) for m_E < 1.97 TeV and sin² (2θ_L^a) ≤ 0.15 form_E = 5 TeV and sin² (2θ_L^a) ≤ 3.88×10^-2 form_E = 10 TeV.

We explore the possibility of distinguishing the SM-like MSSM Higgs boson from the SM Higgs boson via Higgs boson pair production at future muon collider. We study the behavior of the production cross-section in SM and MSSM with Higgs boson mass for various MSSM parameters tan 𝛽 and $m_{A}$. We observe that at fixed CM energy, in the SM, the total cross-section increases with the increase in Higgs boson mass whereas this trend is reversed for the MSSM. The changes that occur for the MSSM in comparison to the SM predictions are quantified in terms of the relative percentage deviation in cross-section. The observed deviations in cross-section for different choices of Higgs boson masses suggest that the measurements of the cross-section could possibly distinguish the SM-like MSSM Higgs boson from the SM Higgs boson.