What Have We Learned About and From F_L(x,Q^2) at HERA?

Abstract

Recently the H1 collaboration has published a ``determination'' of the structure function F_L(x,Q^2) at low x. I address the question of how reliable this determination really is. I argue that it is in fact a consistency check of a given theoretical approach rather than a real determination of the value of F_L(x,Q^2), but potentially a very useful one. I compare the consistency of different approaches, and indeed find that a LO--in--α_s calculation of structure functions is completely ruled out. I also find that the ``determined'' values of F_L(x,Q^2) are surprisingly stable under changes in theoretical approach but, when working consistently within a well-defined theoretical framework, the values of F_L(x,Q^2) implied are somewhat lower than previously quoted.

Tex file, including modification of Harvmac, 17 pages plus 5 figures in .ps files

Cited by in corpus (9)

• Structure Functions of the Nucleon and their Interpretation
• The role of F_L(x,Q^2) in parton analyses
• A phenomenological analysis of the longitudinal structure function at small $x$ and low $Q^2$
• Analytical approach for the approximate solution of the longitudinal structure function with respect to the GLR-MQ equation at small x
• On the Determination of Small x Shadowing Corrections at HERA
• Nonlinear correction to the longitudinal structure function at small x
• A Phenomenological Solution Small $x$ to the Longitudinal Structure Function Dynamical Behavior
• Hard- Pomeron behavior of the Longitudinal Structure Function $F_L$ in the Next- to- Leading- Order at low $x$
• Evolution of the longitudinal structure function at small x