We discuss the status of the Bjorken sum rule in the light of the recent data on the spin structure functions of i) the deuteron obtained by the SMC group at CERN and ii) the neutron by the E142 group at SLAG. Combining the new data with that already obtained for the proton by the EMC group and earlier SLAC/YALE collaborations, and also with stringent bounds obtained on the strange-quark polarisation, we deduce that the Bjorken system of equations is violated at worse than a 2 sigma level. We also show that arguments based on possible higher-twist contributions are unable to account for this discrepancy. In conclusion, an explanation in terms of non-perturbative renormalisation of the relevant Wilson coefficients is presented.
Violation of the bjorken sum rule and system of equations in recent nucleon spin measurements
Ratcliffe P.
Primo
Membro del Collaboration Group
1994-01-01
Abstract
We discuss the status of the Bjorken sum rule in the light of the recent data on the spin structure functions of i) the deuteron obtained by the SMC group at CERN and ii) the neutron by the E142 group at SLAG. Combining the new data with that already obtained for the proton by the EMC group and earlier SLAC/YALE collaborations, and also with stringent bounds obtained on the strange-quark polarisation, we deduce that the Bjorken system of equations is violated at worse than a 2 sigma level. We also show that arguments based on possible higher-twist contributions are unable to account for this discrepancy. In conclusion, an explanation in terms of non-perturbative renormalisation of the relevant Wilson coefficients is presented.
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