München 1997 – wissenschaftliches Programm

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T: Teilchenphysik

T 301: Strukturfunktionen III

T 301.3: Vortrag

Mittwoch, 19. März 1997, 16:30–16:45, 225

Tensor Structure Functions of the Deuteron at low x — •W. Schäfer² and N. N. Nikolaev¹ — ¹ITKP, Universität Bonn and L. D. Landau Inst., Moscow, Russia — ²Institut für Kernphysik, Forschungszentrum Jülich GmbH, Deutschland

We identify and evaluate two new sources of a substantial tensor polarization of the sea parton distributions in the deuteron. The corresponding tensor structure function b₂(x,Q²) rises towards small x similar to F₂(x,Q²). The two new sources of b₂(x,Q²) are diffractive nuclear shadowing, which depends on the alignment of nucleons in the deuteron, and nuclear excess of pions in the deuteron which is sensitive to the spin state of the deuteron. In both cases the crucial rôle is played by interference of the S- and D-waves in the wave function of the deuteron. We predict the about one per cent tensor asymmetry A_T(x,Q²)=b₂(x,Q²)/F_2D(x,Q²) which is order in magnitude larger than the effect evaluated earlier in the impulse approximation. The both mechanisms for tensor structure function break the sum rule ∫dx b₁(x,Q²)=0 suggested earlier.