Glue constraining asymmetries in W, $\gamma$ or Z production at LHC

We propose a class of forward-backward asymmetries with respect to the subprocess c.m. scattering angle in $V$+jet production at hadron colliders, with V being any of (W, Z, $\gamma$, H), which are directly proportional to the gluon distribution $g(x)$. The informations that these asymmetries can provide are complementary of those reachable from measurements of the transverse momentum and/or the rapidity distributions of a $V$ in kinematical regimes where gluon scattering subprocesses dominate. The accuracy which can be reached in the W, Z and $\gamma $ cases, at the upgraded Tevatron and at LHC, should allow a considerable improvement of our knowledge of the gluon distribution function, especially at large x.