2021 Impact factor 4.991
Particles and Fields
Eur. Phys. J. C 29, 171-179 (2003)
DOI: 10.1140/epjc/s2003-01232-3

Double-spin asymmetries in the cross section of $\rho^0$ and $\phi$ production at intermediate energies

The HERMES Collaboration

(Received: 11 February 2003 / Published online: 11 June 2003 )

Double-spin asymmetries in the cross section of electroproduction of $\rho^0$ and $\phi$ mesons on the proton and deuteron are measured at the HERMES experiment. The photoabsorption asymmetry in exclusive $\rho^0$ electroproduction on the proton exhibits a positive tendency. This is consistent with theoretical predictions that the exchange of an object with unnatural parity contributes to exclusive $\rho^0$ electroproduction by transverse photons. The photoabsorption asymmetry on the deuteron is found to be consistent with zero. Double-spin asymmetries in $\rho^0$ and $\phi$ meson electroproduction by quasi-real photons were also found to be consistent with zero; the asymmetry in the case of the $\phi$ meson is compatible with a theoretical prediction which involves $s\bar{s}$ knockout from the nucleon.

© Società Italiana di Fisica, Springer-Verlag 2003