No. 20 (00101)

Family name : Lanyov
Given name : Alexander
Affiliation : Joint Institute for Nuclear Research, Dubna
Abbreviation : JINR, Dubna
E-mail address : lanyov@mail.desy.de
Title : Systematic effects in chi_c --> J/psi gamma background from
        event mixing method and their corrections in data
Authors : A.Lanyov
Abstract : 
The difference between the background for chi_c --> J/psi gamma decay
and the background obtained by the event mixing method is discussed.
It is shown that the difference happens due to kinematical constraints
in the real events, and to the effect of contribution of photons
from chi_c --> J/psi gamma decay to the mixed-event background.
The relative strength of these effects is studied in Monte Carlo.
The correction methods of these physical effects in data are considered.