Search for ${{\boldsymbol X}^{0}}$ (Light Boson) Resonance in ${{\boldsymbol e}^{+}}$ ${{\boldsymbol e}^{-}}$ $\rightarrow$ ${{\boldsymbol \gamma}}{{\boldsymbol \gamma}}{{\boldsymbol \gamma}}$
INSPIRE search
The limit is for $\Gamma\mathrm {( {{\mathit X}^{0}} \rightarrow {{\mathit e}^{+}} {{\mathit e}^{-}} )}\cdot{}\Gamma\mathrm {( {{\mathit X}^{0}} \rightarrow {{\mathit \gamma}} {{\mathit \gamma}} {{\mathit \gamma}} )}/\Gamma _{{\mathrm {total}}}$. $\mathit C$ invariance forbids spin-0 ${{\mathit X}^{0}}$ coupling to both ${{\mathit e}^{+}}{{\mathit e}^{-}}$ and ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit \gamma}}$ .