Göttingen 1997 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
HK: Hadronen und Kerne
HK 8: Struktur von Baryonen und Mesonen I
HK 8.5: Vortrag
Montag, 24. März 1997, 15:15–15:30, HS I
Nucleon matrix elements of higher–twist operators from the instanton vacuum — •J. Balla1, M. Polyakov2,1, and C. Weiss1 — 1Institut f. Theoretische Physik II, Ruhr–Univ. Bochum — 2Petersburg Nuclear Physics Institute, St. Petersburg
Power corrections to the sum rules for polarized structure functions (Bjorken, Ellis–Jaffe) are governed by nucleon matrix elements of QCD operators of twist 3 and 4. We evaluate these matrix elements in the instanton vacuum, using the 1/Nc–expansion in which the nucleon is described as a chiral soliton. We employ a method by which QCD gluon operators are replaced by effective “constituent quark” operators, which can be evaluated in the effective chiral theory derived from instantons [1]. We compare our results to calculations using QCD sum rules.
[1] D. Diakonov, M. Polyakov and C. Weiss, Nucl. Phys. B 461 (1996) 539