摘要
Two photons can annihilate into a neutral pionlike resonance via the anomaly coupling, just like π0γγ in QCD. In some strongly interacting electroweak symmetry breaking models, e.g., technicolor type models, there often exist neutral pionlike resonances. TeV photon colliders have a strong capability to discover such particles, because the standard model background in photon scattering goes through box diagrams and is therefore highly suppressed. In this study, we perform a signal-background comparison. We show that e+e- linear colliders running in γγ mode can discover such neutral pionlike resonances with a decent sensitivity. © 2005 The American Physical Society.