Estimating excited states contamination of $B\to \pi$ form factors using heavy meson chiral perturbation theory

Using Heavy Meson Chiral Perturbation Theory (HMChPT), the $B^{\ast }\pi$ excited states contamination of the $B\to \pi$ vector form factors is computed to NLO in the chiral expansion and in the static limit. The results suggest that the excited states for $h_{\parallel }$ are of the order of a few percent whereas $h_{\perp }$ receives large negative contributions and thus might be significantly underestimated in lattice simulations.