Measurement of the tensor structure function b(1) of the deuteron

The Hermes experiment has investigated the tensor spin structure of the deuteron using the 27.6GeV/c positron beam of DESY HERA. The use of a tensor-polarized deuteron gas target with only a negligible residual vector polarization enabled the first measurement of the tensor asymmetry Azzd and the tensor structure function b1d for average values of the Bjorken variable 0.01<x<0.45 and of the negative of the squared four-momentum transfer 0.5GeV2Q2<5GeV2. The quantities Azzd and b1d are found to be nonzero. The rise of b1d for decreasing values of x can be interpreted to originate from the same mechanism that leads to nuclear shadowing in unpolarized scattering. © 2005 The American Physical Society.