Fragmentation Functions of Charged Hadrons at Next-to-Next-to-Leading Order and Constraints on the Proton Parton...

Area of Science:

• High-energy physics
• Quantum chromodynamics
• Hadron physics

Background:

• Fragmentation functions describe hadronization in high-energy collisions.
• Previous analyses lacked global data at higher perturbative orders.
• Parton distribution functions (PDFs) are crucial for understanding nucleon structure.

Purpose of the Study:

• To perform the first global analysis of fragmentation functions for light charged hadrons (pions, kaons) at full next-to-next-to-leading order (NNLO) in quantum chromodynamics.
• To investigate the impact of this new analysis on Parton Distribution Functions (PDFs).
• To test collinear factorization with experimental data.

Main Methods:

• Global analysis of fragmentation functions using world data from electron-positron annihilation and deep-inelastic scattering experiments.
• Calculation performed at full next-to-next-to-leading order (NNLO) in quantum chromodynamics.
• Investigation of the influence of hadron production data on strange quark PDFs.

Main Results:

• The first global NNLO fragmentation functions for π^{±} and K^{±} are presented.
• Collinear factorization is validated for both low- and high-momentum transfer regimes.
• Global data on hadron production favor reduced asymmetry in strange quark PDFs compared to predictions from inclusive data-based PDFs.

Conclusions:

• The NNLO fragmentation functions provide a more precise description of hadronization.
• The study refines our understanding of the nucleon's internal structure, particularly the strange quark sea.
• This work offers crucial inputs for future precision studies in high-energy physics.