SuperCHIC: Monte Carlo Event Generator for Central Exclusive Production

The enclosed standalone Fortran code provides public access to the Monte Carlo generator described in:

Please reference the relevant papers if you use the programme for a publication.

The program currently generates unweighted events for central exclusive J/ψ, Υ, γγ, χ_qJ, η_q and meson pair (ππ, ηη, η'η', ηη', ρρ) production, with q=(b,c) and J=(0,1,2).

The decay of χ_cJ states is generated via the transition

χ_c → J/ψ γ → μ⁺ μ^- γ

and χ_bJ via

χ_b → ϒ γ → μ⁺ μ^- γ

Alternatively, χ_qJ and η_q decays can be generated via the two body transition

X → h₁ + h₂

with h_(1,2) scalar or fermionic states of mass m_h. χ_c0 four-body decays are also included

X → h₁ + h₂ + h₃ + h₄

Photon induced exclusive J/ψ, ψ(2S) and Υ production is generated via the leptonic decay

V → l⁺l^-

ψ(2S) → J/ψ π⁺π^-

π(η) → γγ

Note meson pair and γγ CEP only generated for M_X> 2 GeV. Processes can be generated at cms energies of √s = 1.96, 7, 8, 10 and 14 TeV and χ_cJ, η_c production can also be generated at √s= 500 GeV. Meson pair CEP can also be generated at √s= 0.3 and 0.9 TeV.