Pseudoscalar pair production via off-shell Higgs in composite Higgs models

We propose a new type of search for a pseudoscalar particle eta pair produced via an off-shell Higgs, pp -> h* -> eta eta. The search is motivated by a composite Higgs model in which the eta is extremely narrow and decays almost exclusively into Z(gamma) in the mass range 65 GeV less than or similar to m(eta) less than or similar to 160 GeV. We devise an analysis strategy to observe the novel Z(gamma)Z(gamma) channel and estimate potential bounds on the Higgs-eta coupling. The experimental sensitivity to the signatures depends on the power to identify fake photons and on the ability to predict large photon multiplicities. This search allows us to exclude large values of the compositeness scale f, being thus complementary to other typical processes.