1. Transverse target spin asymmetries in exclusive $\rho^0$ muoproduction
- Author
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COMPASS collaboration (213 authors), Bordalo, P, Franco, C, Nunes, A.S, Quaresma, M, Quintans, C, Ramos, S, Silva, L, and Stolarski, M
- Subjects
High Energy Physics::Experiment ,Nuclear Experiment - Abstract
Exclusive production of $\rho^0$ mesons was studied at the COMPASS experiment by scattering 160 GeV/$c$ muons off transversely polarised protons. Five single-spin and three double-spin azimuthal asymmetries were measured as a function of $Q^2$, $x_{Bj}$, or $p_{T}^{2}$. The $\sin \phi_S$ asymmetry is found to be $-0.019 \pm 0.008(stat.) \pm 0.003(syst.)$. All other asymmetries are also found to be of small magnitude and consistent with zero within experimental uncertainties. Very recent calculations using a GPD-based model agree well with the present results. The data is interpreted as evidence for the existence of chiral-odd, transverse generalized parton distributions.
- Published
- 2014