Calculate the cross-sections of the processes e + e - + - and e +

Calculate the cross-sections of the processes e⁺e^- →μ⁺μ^- and e⁺e^- → hadrons at the J/ψ peak (m_ψ = 3.097 GeV) and for the ratio of the former to its value in the absence of resonance. Neglect the masses and use the Breit–Wigner approximation [Γ_e/Γ = 5.9%, Γ_h/Γ = 87.7%].