Small x: Two Pomerons!

Abstract

Regge theory provides a very simple and economical description of data for (i) the proton structure function with x<0.07 and all available Q^2 values, (ii) the charm structure function, and (iii) gamma p --> J/psi p. The data are all in agreement with the assumption that there is a second pomeron, with intercept about 1.4 . They suggest also that the contribution from the soft pomeron is higher twist. This means that there is an urgent need to make perturbative evolution compatible with Regge theory at small and not-so-small x, and to reassess the magnitude of higher-twist contributions at quite small x.

13 pages, plain tex, with 8 figures embedded using epsf. (Two typos corrected and a reference added.)

References in corpus (4)

• Measurement of the Proton Structure Function F_2 and σ_{tot}^{γ^* p} at Low Q^2 and Very Low x at HERA
• D* Production in Deep Inelastic Scattering at HERA
• Measurement of Elastic $J/\psi$ Photoproduction at HERA
• The BFKL-Regge Phenomenology of Deep Inelastic Scattering

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