Search for the Higgs boson in events with isolated photons at LEP 2

A search for the Higgs boson in final states with one, two or three isolated photons has been performed based on data taken at LEP 2 by the DELPHI detector. The data analysed correspond to a total integrated luminosity of 67.5 pb(-1) at centre-of-mass energies of 161 GeV (9.7 pb(-1)), 172 GeV (10.1 pb(-1)) and 183 GeV (47.7 pb(-1)). No evidence for the processes e(+)e(-) --> H gamma with H --> b (b) over bar or gamma gamma and e(+)e(-) --> Hq (q) over bar with H --> gamma gamma was observed. Model-independent limits on sigma(e(+)e(-) --> H gamma) x BR(H --> b (b) over bar), sigma(e(+)e(-) --> Hq (q) over bar) x BR(H --> gamma gamma) and sigma(e(+)e(-) --> H gamma) x BR(H --> gamma gamma) are set, as well as model-dependent limits on Higgs boson anomalous couplings to vector bosons. (C) 1999 Published by Elsevier Science B.V. All rights reserved.