AKK Update: Improvements from New Theoretical Input and Experimental Data

S. Albino; B. A. Kniehl; G. Kramer

Paper

AKK Update: Improvements from New Theoretical Input and Experimental Data

Abstract

We perform a number of improvements to the previous AKK extraction of fragmentation functions for

and

particles at next-to-leading order. Inclusive hadron production measurements from

reactions at BRAHMS, CDF, PHENIX and STAR are added to the data sample. We use the charge-sign asymmetry of the produced hadrons in

reactions to constrain the valence quark fragmentations. Data from

reactions in regions of smaller

and lower

are added. Hadron mass effects are treated for all observables and, for each particle, the hadron mass used for the description of the

reaction is fitted. The baryons' fitted masses are found to be only around 1% above their true masses, while the values of the mesons' fitted masses have the correct order of magnitude. Large

resummation is applied in the coefficient functions of the

reactions, and also in the evolution of the fragmentation functions, which in most cases results in a significant reduction of the minimized

. To further exploit the data, all published normalization errors are incorporated via a correlation matrix.