Deep inelastic leptoproduction of spin-one hadrons
A. Bacchetta, P. J. Mulders
TL;DR
This work extends the leading-twist description of deep inelastic scattering to spin-1 hadrons, introducing a comprehensive framework of spin-1 distribution and fragmentation functions with transverse momentum dependence and time-reversal odd contributions. It formalizes the spin-1 density matrix and correlation functions, derives the hadronic tensor, and provides a complete set of cross sections for one-particle inclusive leptoproduction under all beam/target polarization configurations, including tensor polarization in the final state. A key result is that LT configurations can access the chiral-odd transversity distribution $h_1(x)$ via a T-odd fragmentation function $H_{1LT}(z)$ without requiring explicit transverse momentum measurements. The paper thus establishes a rigorous theoretical base for extracting and constraining the new spin-1 functions in vector-meson leptoproduction, with rho decays providing a practical polarization observable.
Abstract
In this paper we analyze deep inelastic one-particle inclusive processes for the case of spin-one targets or for the case of spin-one produced hadrons, such as rho mesons. This allows the measurement of new distribution and fragmentation functions not available in the spin-half case, and provides new ways to probe functions otherwise difficult to measure. We will analyze only contributions leading order in 1/Q, but we will include effects of the transverse momentum of partons. We also include time-reversal odd functions.
