On the possibility of discrimination between pi0, eta, omega, K0(S) mesons and a photon based on the calorimeter information in the CMS detector

The possibility of separating the $\pi^0, \eta, \omega$ and $K^0_s$ meson background from the signal photons produced directly in $pp$ collisions is analyzed. The rejection factors for two pseudorapidity regions 0.4<\eta<1.0$ and 1.6<\eta<2.0$ and six Et values, 20, 40, 60, 80, 100 and 200 GeV, are calculated for a case when only the calorimeter information is used. The cases of $\eta, \omega$ and $K^0_s$ mesons decaying through the neutral and charged channels are considered separately.