Next-to-MLLA corrections to single inclusive kt-distributions and 2-particle correlations in a jet

TL;DR

This paper calculates next-to-MLLA corrections to the hadronic transverse momentum spectrum and two-particle correlations inside high-energy jets, showing improved agreement with experimental data and highlighting small non-perturbative effects.

Contribution

It introduces NMLLA corrections to jet spectra and correlations, extending previous MLLA calculations and improving agreement with experimental measurements.

Findings

NMLLA corrections improve agreement with CDF data

Two-particle correlations are predicted at NMLLA

Small non-perturbative contributions are identified

Abstract

The hadronic kt-spectrum inside a high energy jet is determined including corrections of relative magnitude O{\sqrt{\alpha_s}} with respect to the Modified Leading Logarithmic Approximation (MLLA), in the limiting spectrum approximation (assuming an infrared cut-off Q0 =Lambda_{QCD}) and beyond Q_0\ne\Lambda_{QCD}. The results in the limiting spectrum approximation are found to be, after normalization, in impressive agreement with preliminary measurements by the CDF collaboration, unlike what occurs at MLLA, pointing out small overall non-perturbative contributions. Within the same framework, 2-particle correlations inside a jet are also predicted at NMLLA and compared to previous MLLA calculations.