Revisiting non-perturbative effects in the jet broadenings
Yu. L. Dokshitzer, G. Marchesini, G. P. Salam
TL;DR
The paper addresses non-perturbative power corrections to jet broadening in $e^+e^-$ annihilation, demonstrating that the NP contribution is not a universal constant but depends on the broadening variable $B$ through the interplay with perturbative dynamics. It develops a dispersive framework with the Milan factor and Sudakov resummation to separate perturbative and non-perturbative radiation, deriving explicit $B$-dependent shift functions $D_1(B)$ and $D_T(B)$ and their asymptotics for the single-jet, wide-jet, and total broadening distributions and their means. The authors provide analytic NP corrections to the means and to the distributions, enabling improved phenomenology and a test of the universality of confinement effects in jet shapes. Overall, the results connect infrared-sensitive jet observables to the infrared behavior of QCD via a consistent, testable framework that aligns jet-broadening data with confinement universality ideas.
Abstract
We show that taking into account the interplay between perturbative and non-perturbative effects, the power-suppressed shift to the broadening distributions becomes B dependent, and the non-perturbative contribution to the mean values becomes proportional to 1/(Q\sqrt{\as(Q)}). The new theoretical treatment greatly improves the consistency of the phenomenology with the notion of the universality of confinement effects in jet shapes.