Instantons, Spin Crisis and High Q² Anomaly at HERA

الأصل · EN

The contribution of the nonperturbative quark-gluon interaction induced by the instantons to g₁ᵖ(x,Q²) and F₂ᵖ(x,Q²) structure functions is estimated. It is shown that nontrivial Q² dependence of the instanton contribution to g₁ᵖ(x,Q²) 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 F₂ᵖ(x,Q²) 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 Q² and x.