  Along with $\pi^0$ and $\eta$ mesons, a resonance structure in the invariant
mass spectrum of two photons at $M_{\gamma\gamma}= 360 \pm 7 \pm 9$ MeV is
observed in the reaction $d C\to\gamma + \gamma +X$ at momentum 2.75 GeV/c per
nucleon. Estimates of its width and production cross section are $\Gamma = 63.7
\pm 17.8$ MeV and $\sigma_{\gamma\gamma}=98\pm24^{+93}_{-67} {\rm \mu b}$,
respectively. The collected statistics amount to $2339 \pm 340$ events of
$1.5\cdot 10^6$ triggered interactions of a total number $\sim 10^{12}$ of
$d$C-interactions. This resonance structure is not observed in $p$C collisions
at the beam momentum 5.5 GeV/c. Possible mechanisms of this ABC-like effect are
discussed.
