Azimuthal asymmetry in semi-inclusive deep inelastic scattering off nuclei as probe forq^

Abstract

The energy loss parameter (q) over cap is one of the fundamental transport parameters of hadronic matter. Using the twist-4 collinear approach, we show that the cos phi azimuthal asymmetry in unpolarized semi-inclusive deeply inelastic scattering off a large nucleus at intermediate transverse momentum is a sensitive observable for its determination. The effect is due to the suppression of the azimuthal asymmetry by final-state multiple scattering.