The cos2φ asymmetry of Drell–Yan and J/ψ production in unpolarized pp̄ scattering V. Barone, Zhun Lu and Bo-Qiang Ma Eur. Phys. J. C, 49 4 (2007) 967-971 Published online: 19 December 2006 DOI: 10.1140/epjc/s10052-006-0174-6