Next-to-modified leading logarithmic approximation corrections to single inclusivek⊥distributions and two-particle correlations in a jet

Abstract

The hadronic ${k}_{\ensuremath{\perp}}$-spectrum inside a high-energy jet is determined including corrections of relative magnitude $\mathcal{O}(\sqrt{{\ensuremath{\alpha}}_{s}})$ with respect to the Modified Leading Logarithmic Approximation (MLLA) in the limiting spectrum approximation (assuming an infrared cutoff ${Q}_{0}={\ensuremath{\Lambda}}_{\mathrm{QCD}}$) and beyond (${Q}_{0}\ensuremath{\ne}{\ensuremath{\Lambda}}_{\mathrm{QCD}}$). 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 nonperturbative contributions. Within the same framework, 2-particle correlations inside a jet are also predicted at next-to-MLLA and compared to previous MLLA calculations.