The Hermes experiment has investigated the tensor spin structure of the deuteron using the 27.6 GeV/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 A(zz)(d) and the tensor structure function b(1)(d) for average values of the Bjorken variable 0.01 << x >< 0.45 and of the negative of the squared four-momentum transfer 0.5 GeV2<< Q(2)>< 5 GeV2. The quantities A(zz)(d) and b(1)(d) are found to be nonzero. The rise of b(1)(d) for decreasing values of x can be interpreted to originate from the same mechanism that leads to nuclear shadowing in unpolarized scattering.
Measurement of the tensor structure function b(1) of the deuteron
CIULLO, Giuseppe;CONTALBRIGO, Marco;FERRETTI, Paola;LENISA, Paolo;MASOLI, Francesco Antonio;REGGIANI, DAVIDE;STANCARI, Michelle Dawn;STATERA, Marco;
2005
Abstract
The Hermes experiment has investigated the tensor spin structure of the deuteron using the 27.6 GeV/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 A(zz)(d) and the tensor structure function b(1)(d) for average values of the Bjorken variable 0.01 << x >< 0.45 and of the negative of the squared four-momentum transfer 0.5 GeV2<< Q(2)>< 5 GeV2. The quantities A(zz)(d) and b(1)(d) are found to be nonzero. The rise of b(1)(d) for decreasing values of x can be interpreted to originate from the same mechanism that leads to nuclear shadowing in unpolarized scattering.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
