Freiburg 1998 – scientific programme

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T: Teilchenphysik

T 203: Strukturfunktionen II

T 203.1: Talk

Tuesday, March 24, 1998, 08:30–08:45, HS C

Strange Quark Contributions to Nucleon Structure Functions — •O. Schr"oder, H. Reinhardt, and H. Weigel — Institut f"ur Theoretische Physik, Universit"at T"ubingen, D-72076 T"ubingen

Recently it has been shown that nucleon structure functions can efficiantly be computed [1] from the chiral soliton [2] of the Nambu–Jona–Lasinio (NJL) model. This model can straightforwardly be generalized to include strange quarks [3]. This extension of the NJL is used to evaluate the contribution of strange degrees of freedom to both the unpolarized and polarized structure functions of the nucleon. Within this model calculation the structure functions are obtained at a low energy scale and a DGLAP treatment is mandatory to evolve them to the scale relevant to the experiments. While the unpolarized structure functions are constrained by the sum rule for zero strangeness, the polarized ones are especially interesting in the context of the “proton spin puzzle”. The important effects of flavor symmetry breaking on the nucleon wave–function are incorporated according to the Yabu–Ando approach [4].

[1] H. Weigel, L. Gamberg, H. Reinhardt, Phys. Lett. B399 (1997) 287; Phys. Rev. D55 (1997) 6910.

[2] R. Alkofer, H. Reinhardt, H. Weigel, Phys. Rep. 265 (1996) 139.

[3] H. Weigel, Intl. J. Mod. Phys. A11 (1996) 2419.

[4] H. Yabu, H. Ando, Nucl. Phys. B301 (1988) 601.

Supported in part by the Deutsche Forschungsgemeinschaft (DFG) under contract
Re 856/2–3.