The spin structure of the nucleon

✍ Scribed by J.-M. Le Goff

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 687 KB
• Volume: 74
• Category: Article
• ISSN: 0920-5632
• DOI: 10.1016/s0920-5632(99)00151-6

✦ Synopsis

We present the final results of the spin asymmetries A1 and the spin structure functions g1 of the proton and the deuteron from the SMC. In the region I < 0.02 we use a new method for the determination of Al. The usual method employs inclusive scattering events and includes a large radiative background at low z, while the new method minimises the radiative background by selecting events with at least one hadron as well as a muon in the Snal state. Using these data and other presently available data we performed a next-to-leading order QCD analysis of the spin structure function 91. We present results for the first moments of the proton, deuteron and neutron structure functions, and determine singlet and non-singlet parton distributions. We also test the Bjorken sum rule and find agreement with the theoretical prediction at the level of 10%.