Comment on Quarks and Gluons at Small $x$ and the Sdis Factorization Scheme

Abstract

I present some comments on the partonic interpretation of the HERA data on the proton structure function. The effects of the resummation of the leading and next-to-leading $\ln x$-contributions are discussed. A new factorization scheme, in which these resummation effects are absorbed into a steep redefinition of the gluon density, is introduced and its (possible) interpretation and phenomenological relevance are suggested.

Comments: 17 pages (+1 fig. available in hard copy upon request to catani@fi.infn.it or catani@vxcern.cern.ch), LateX