Instantons, Spin Crisis and High $Q^2$ Anomaly at HERA
Abstract
The contribution of the nonperturbative quark-gluon interaction induced by the instantons to $g_1^p(x,Q^2)$ and $F_2^p(x,Q^2)$ structure functions is estimated. It is shown that nontrivial $Q^2$ dependence of the instanton contribution to $g_1^p(x,Q^2)$ allows us to explain the observed decreasing of the part of the proton spin carried by quarks without involving a large positive gluon polarization. It is demonstrated that the anomalous enhancement of the instanton contribution to $F_2^p(x,Q^2)$ structure function, due to multiple emission of the gluons from instanton vertex, can be one of the reasons for the excess of the DIS events at HERA at high $Q^2 $ and $x$.
- Publication:
-
arXiv e-prints
- Pub Date:
- October 1997
- DOI:
- 10.48550/arXiv.hep-ph/9710540
- arXiv:
- arXiv:hep-ph/9710540
- Bibcode:
- 1997hep.ph...10540K
- Keywords:
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- High Energy Physics - Phenomenology
- E-Print:
- 9 pages, Latex, 3 figures. To appear in Proc. Workshop ``Physics with Polarized Protons at HERA'' August 1997,DESY-Zeuthen