  We study the possibility of observing a light pseudo-scalar $a$ at LHCb. We
target the mass region $1 \lesssim m_a \lesssim 60$ GeV and various decay
channels, some of which have never been considered before: muon pairs, tau
pairs, $D$ meson pairs, and di-photon. We interpret the results in the context
of models of 4D Composite Higgs and Partial Compositeness in particular.
