Hard photon bremsstrahlung effects in hyperon semileptonic decays

An efficient Monte Carlo method for photon bremsstrahlung calculations in semileptonic decays is described. This method is useful for order-alpha radiative correction calculations, and for event generations in off-line Monte Carlo simulation programs. The order-alpha bremsstrahlung amplitude in hyperon semileptonic decays is given by using the Low-theorem, and the bremsstrahlung amplitude squared is calculated for unpolarized decays. Numerical calculation results are presented for n --> <pe(nu)over bar>, mu --> <e(nu)over bar(e) nu(mu)>, Sigma(-) --> <ne(nu)over bar> and Lambda --> <pe(nu)over bar> decays. The general features of the Monte Carlo method might be useful for photon bremsstrahlung calculations in other decay and collision processes. (C) 1997 Published by Elsevier Science B.V.