Non-perturbative effects in the energy-energy correlation

TL;DR

This paper extends the perturbative calculation of the energy-energy correlation in electron-positron annihilation by including leading non-perturbative effects using the dispersive method, revealing how these contributions scale with energy.

Contribution

It introduces a method to incorporate leading non-perturbative power corrections into the energy-energy correlation analysis, linking them to other observables through a universal strong coupling hypothesis.

Findings

Non-perturbative 1/Q contributions from quark-gluon correlations.

Smaller logarithmic non-perturbative effects from quark-antiquark correlations.

Slower decrease of power-suppressed contributions in the back-to-back region.

Abstract

The fully resummed next-to-leading-order perturbative calculation of the energy-energy correlation in $e^+e^-$ annihilation is extended to include the leading non-perturbative power-behaved contributions computed using the ``dispersive method'' applied earlier to event shape variables. The correlation between a leading (anti)quark and a gluon produces a non-perturbative 1/Q contribution, while non-perturbative effects in the quark-antiquark correlation give 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 small non-integer powers of 1/Q, as a result of the interplay with perturbative effects. The hypothesis of a universal low-energy form for the strong coupling relates the coefficients of these contributions to those measured for other observables.