Fast leading particles and long-range rapidity correlations between pions

The long-range rapidity correlations between two produced particles due to the existence of very fast leading particles are calculated using the high-energy data on single diffraction dissociation as input. The method of calculation is to a large extent analytic. The long-range correlations are found to be equally important as short range effects in interpreting experimental data on two-particle correlations. The results are not sensitive to the detailed properties of diffraction dissociation. (16 refs).