Lam-Tung relation breaking in $Z$ boson production as a probe of SMEFT effects

Xu Li, Bin Yan, C. -P. Yuan

The violation of Lam-Tung relation in the high-$p_T^{\ell \ell }$ region of the Drell-Yan process at the LHC presents a long-standing discrepancy with the standard model prediction a…