Studies of Higher Twist and Higher Order Effects in NLO and NNLO QCD Analysis of Lepton-Nucleon Scattering Data on F_2 and R =sigma_L/sigma_T

TL;DR

This paper investigates higher twist effects in lepton-nucleon scattering by analyzing F_2 and R data within NLO and NNLO QCD frameworks, finding that NNLO fits eliminate the need for higher twist contributions.

Contribution

It provides a detailed comparison of NLO and NNLO QCD fits to scattering data, showing that NNLO calculations can describe the data without higher twist terms.

Findings

Higher twist contributions are necessary at NLO for low Q^2.

NNLO fits describe the data without higher twist effects.

Difference between NLO and NNLO parton distributions is estimated.

Abstract

We report on the extraction of the higher twist contributions to F_2 and R = sigma_L/sigma_T from the global NLO and NNLO QCD fits to lepton nucleon scattering data over a wide range of Q^2. The NLO fits require both target mass and higher twist contributions at low Q^2. However, in the NNLO analysis, the data are described by the NNLO QCD predictions (with target mass corrections) without the need for any significant contributions from higher twist effects. An estimate of the difference between NLO and NNLO parton distribution functions is obtained.