Neutrino Production of a Charmed Meson and the Transverse Spin Structure of the Nucleon

We calculate the amplitude for exclusive neutrino production of a charmed meson on an unpolarized target in the collinear QCD approach, where generalized parton distributions (GPDs) factorize from perturbatively calculable coefficient functions. We demonstrate that the transversity chiral odd GPDs contribute to the transverse cross section if the hard amplitude is calculated up to order $m_c/Q$. We show how to access these GPDs through the azimuthal dependence of the $\nu N\to {\mu }^{-}{D}^{+}N$ differential cross section.

Figure 1

Feynman diagrams for the factorized amplitude for the ${\nu }_{\mu }N\to {\mu }^{-}{D}^{+}{N}^{\prime }$ process; the thick line represents the heavy quark. In the Feynman gauge, diagram (a) involves convolution with both the transversity GPDs and the chiral even ones, whereas diagram (b) involves only chiral even GPDs.