CONSTITUENT QUARKS AND PARTON DISTRIBUTIONS

摘要

The high energy parton distribution when evolved to a low energy scale appears to indicate that a valence picture of hadron structure arises. We have developed a formalism based on a laboratory partonic description which connects the parton distributions with the momentum distributions of a quark model. The formalism uses Next to Leading Order evolution and has been defined to produce the right support for the parton distributions. In this scheme we have analyzed the polarized and unpolarized data and shown that well-known Quark Models lead to a qualitative description of the data. However, if one aims at a quantitative agreement, these conventional low energy models have to be changed to include higher momentum and angular momentum components. Moreover, if the present gluon distributions, despite their indirect extraction, are taken to be an accurate description of nature, the need of primordial gluons or constituent quark substructure is an outcome of our calculation. [References: 65]