Non-perturbative effects in the energy-energy correlation

The fully resummed next-to-leading-order perturbative calculation of theenergy-energy correlation in $e^+e^-$ annihilation is extended to include theleading non-perturbative power-behaved contributions computed using the``dispersive method'' applied earlier to event shape variables. The correlationbetween a leading (anti)quark and a gluon produces a non-perturbative 1/Qcontribution, while non-perturbative effects in the quark-antiquark correlationgive rise to a smaller contribution $\ln Q^2/Q^2$. In the back-to-back region,the power-suppressed contributions actually decrease much more slowly, as smallnon-integer powers of 1/Q, as a result of the interplay with perturbativeeffects. The hypothesis of a universal low-energy form for the strong couplingrelates the coefficients of these contributions to those measured for otherobservables.Comment: 41 pages, LaTeX, 4 figures, uses JHEP.cl