Studies of Higher Twist and Higher Order Effects in NLO and NNLO QCD Analysis
نویسندگان
چکیده
We report on the extraction of the higher twist contributions to F2 and R = σL/σT from 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.
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