Single muons recombinations as a determination of the combinatorial background in muon pair measurements and estimation of the associated error

Any pair measurement is accompanied by a combinatorial background of uncorrelated elements. This background increases with the average number of single elements per event. In ultrarelativistic heavy ion collisions the subtraction of this background is crucial for the study of the muon pair production. After a short description of the principles of an estimate of this background, one of these methods, based on the recombinations of single muons extracted from the measured muon pairs, is extensively studied and the error associated to these recombinations is determined both from analytical calculations and from studies of simulated and experimental samples. The optimization of the number of combinations is also considered.