ar X iv : h ep - p h / 99 02 40 8 v 3 1 2 M ay 1 99 9 HARD - PHOTON EMISSION IN e + e − → f̄ f WITH REALISTIC CUTS
نویسنده
چکیده
We derive compact analytical formulae of the Bonneau-Martin type for the reaction e + e − → ¯ f f γ with cuts on minimal energy and acollinearity of the fermions, where the photons may be emitted both from the initial or final states. Soft-photon exponentiation is also taken into account. One of the cleanest scattering processes at elementary particle accelerators is fermion-pair production in e + e − annihilation, potentially accompanied by one or few photons: e + e − → ¯ f f + (n)γ. (1) Initial-state corrections may be written as an integral over the (normalized) invariant mass squared R = s ′ /s of the final-state fermion pair: σ ini T (s) = dR σ 0 (s ′) ρ ini T (R), (2) where σ 0 (s ′) is an effective Born cross-section. The radiator function ρ ini T (R) for the initial-state first-order corrections to the total cross-section σ T , with soft-photon exponentiation, is [1]: ρ ini T (R) =
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