Results from SMC on the spin-dependent structure function gp1 of the proton

The spin-dependent structure function gp1 has been measured by deep inelastic scattering of polarized muons off polarized protons at 190 GeV incident muon energy. The data cover a kinematic range of 1<Q2<80GeV2 and 0.003<x<0.6, where -Q2 is the squared 4-momentum transfer and x is the Bjorken scaling variable. The first moment Γp1=∫10gp1dx=0.152±0.015(stat.)±0.018(syst.) is smaller than the prediction of the Ellis-Jaffe sum rule by one standard deviation. This result leads to a contribution of the quark spins to the proton spin of δΣ=0.36±0.21. All results presented here are preliminary. ((orig.))