Multi-photon final states in e(+)e(-) collisions at root s=130-172 GeV

The process e(+)e(-)-->gamma gamma(gamma) is studied using data recorded with the OPAL detector at LEP. The data sample corresponds to a total integrated luminosity of 25.38 pb(-1) taken at centre-of-mass energies of 130-272 GeV. The measured cross-sections agree well with the expectation from QED, In a combined fit using data from all centre-of-mass energies. the angular distribution is used to obtain improved limits on the cut-off parameters: Lambda(+) > 195GeV and Lambda(-) > 210GeV (95% CL), In addition, limits on nonstandard e(+)e(-)gamma couplings and contact interactions, as well as a 95% CL mass limit for an excited electron. M-e*, > 194 GeV for an e(+)e(-)gamma coupling kappa = 1, are determined.