Determination of pion and kaon fragmentation functions including spin asymmetries data in a global analysis

TL;DR

This paper develops new pion and kaon fragmentation functions using a comprehensive global analysis of electron-positron annihilation and semi-inclusive deep inelastic scattering data, including recent results, and applies them to predict top-quark decay distributions.

Contribution

It introduces a new functional form of fragmentation functions at NLO, incorporating spin asymmetry data and breaking symmetry assumptions, enhancing the understanding of hadronization processes.

Findings

Fragmentation functions agree well with diverse experimental data.

Asymmetry data helps distinguish quark and anti-quark fragmentation.

Predictions for top-quark decay distributions are provided using the new functions.

Abstract

We present new functional form of pion and kaon fragmentation functions up to next-to-leading order obtained through a global fit to single-inclusive electron-positron annihilation data and also employ, the semi-inclusive deep inelastic scattering asymmetry data from HERMES and COMPASS to determine fragmentation functions. Also we apply very recently electron-positron annihilation data from BaBar and Belle at $\sqrt{s}=10.54$ GeV and $\sqrt{s}=10.52$ GeV, respectively. In this analysis we consider the impression of semi-inclusive deep inelastic scattering asymmetry data on the fragmentation functions, where the produced hadrons of different electric charge are identified. We break symmetry assumption between quark and anti-quark fragmentation functions for favored partons by using the asymmetry data. The results of our analysis are in good agreement with electron-positron annihilation data and also with all the semi-inclusive deep inelastic scattering asymmetry data. Also we apply the obtained fragmentation functions to predict the scaled-energy distribution of $\pi^+/K^+$ inclusively produced in top-quark decays at next-to-leading order using the zero-mass variable-flavor-number scheme exploiting the universality and scaling violations of fragmentation functions.