RECOIL EFFECT ON MULTIPLICITY CORRELATION

The kinematical constraint due to energy-momentum conservation reduces the multiplicity correlation in e+e--annihilation (recoil effect). The correction starts at the second order in the expansion in powers of square-root alpha(s) [i.e. O(alpha(s))]. The O(alpha(s)) correction to the squared dispersion r2 of the scaled multiplicity distribution is evaluated. It is found so large that the truncated expansion is inadequate at current energies. An evaluation without the expansion gives a reduced correction, with which the prediction remains positive down to low energies. The recoil effect makes the prediction closer to the experimental data.