R. Barate et al., Search for gamma gamma decays of a Higgs boson produced in association with a fermion pair in e(+)e(-) collisions at LEP, PHYS LETT B, 487(3-4), 2000, pp. 241-252
A search for yy decays of a Higgs boson is performed in the data sample col
lected at LEP with the ALEPH detector between 1991 and 1999. This correspon
ds to an integrated luminosity of 672pb(-1) at centre-of-mass energies rang
ing from 88 to 202 GeV. The search is based on topologies arising from a Hi
ggs boson produced in association with a fermion pair via the Higgs-strahlu
ng process e(+)e(-)--> Hf (f) over bar with f (f) over bar = nu<(nu)over ba
r>, e(+)e(-), mu(+)mu(-),tau(+)tau(-) or q (q) over bar. Twenty-two events
are selected in the data, while 28 events are expected from standard model
processes. An upper limit is derived, as a function of the Higgs boson mass
, on the product of the e(+)e(-)--> Hf (f) over bar: cross section and the
H --> gamma gamma branching fraction. In particular, a fermiophobic Higgs b
oson produced with the standard model cross section is excluded at 95% conf
idence level for all masses below 100.7 GeV/c(2). (C) 2000 Elsevier Science
B.V. All rights reserved.