A1
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Measurement of the spin dependent structure function g1(x) of the proton.

The Spin Muon (SMC) collaboration Adams, D. ; Adeva, B. ; Arik, E. ; et al.
Phys.Lett.B 329 (1994) 399-406, 1994.
Inspire Record 373036 DOI 10.17182/hepdata.48171

: We have measured the spin-dependent structure function $g_1~p$ of the proton in deep inelastic scattering of polarized muons off polarized protons, in the kinematic range $0.003<x<0.7$ and $1\,\mbox{GeV}~2<Q~2<60\,\mbox{GeV}~2$. Its first moment, $\int_0~1 g_1~p(x) dx $, is found to be $0.136 \pm 0.011\,(\mbox{stat.})\pm 0.011\,(\mbox{syst.})$ at $Q~2=10\,\mbox{GeV}~2$. This value is smaller than the prediction of the Ellis--Jaffe sum rule by two standard deviations, and is consistent with previous measurements. A combined analysis of all available proton, deuteron and neutron data confirms the Bjorken sum rule to within $10\%$ of the theoretical value.

3 data tables
Table 1

Results on the virtual photon proton asymmetry.

Table 2

Results on the spin structure function of the proton.

Table 3

Data for g1 at fixed Q**2 = 10 GeV (assuming no Q**2 dependence of A1).


A measurement of the spin asymmetry and determination of the structure function g(1) in deep inelastic muon proton scattering.

The European Muon collaboration Ashman, J. ; Badelek, B. ; Baum, Guenter ; et al.
Phys.Lett.B 206 (1988) 364, 1988.
Inspire Record 252744 DOI 10.17182/hepdata.29952

The spin asymmetry in deep inelastic scattering of longitudinally polarised muons by longitudinally polarised protons has been measured over a large x range (0.01< x <0.7). The spin-dependent structure function g 1 ( x ) for the proton has been determined and its integral over x found to be 0.114±0.012±0.026, in disagreement with the Ellis-Jaffe sum rule. Assuming the validity of the Bjorken sum rule, this result implies a significant negative value for the integral of g 1 for the neutron. These values for the integrals of g 1 lead to the conclusion that the total quark spin constitutes a rather small fraction of the spin of the nucleon.

1 data table
Table 1

THE AVERAGE VALUES OF Q**2 IN EACH X-BIN ARE AS FOLLOWS: X=0.015,Q2=3.5: X=0.025,Q2=4.5: X=0.035,Q2=6.0: X=0.050,Q2=8.0: X=0.078,Q2=10.3: X=0.124,Q2=12.9: X=0.175,Q2=15.2: X=0.248,Q2=18.0: X=0.344,Q2=22.5: X=0.466,Q2=29.5.