CHINA CTR ADV SCI & TECHNOL,WORLD LAB,BEIJING 100080,PEOPLES R CHINA
; BEIJING UNIV,DEPT PHYS,BEIJING 100871,PEOPLES R CHINA
; CARNEGIE MELLON UNIV,DEPT PHYS,PITTSBURGH,PA 15213
In this paper, we investigate the effects of the quantity sigma(TS) on the spin structure functions of nucleons in the resonance region. The Schwinger sum rule for the spin structure function g(2)(x,Q(2)) at the real photon limit is derived for the nucleon treated as a composite system, and it provides a crucial constraint on the longitudinal transition operator which has not been treated consistently in the literature. The longitudinal amplitude S-1/2 is evaluated in the quark model with the transition operator that generates the Schwinger sum rule. The numerical results of the quantity sigma(TS) are presented for both spin structure functions g(1)(x,Q(2)) and g(2)(x,Q(2)), in the resonance region. Our results show that this quantity plays an important role in the low Q(2) region, which can be tested in future experiments at CEBAF.