Probing New Physics with $b \to u \ell ν_{\ell}$ induced decays

We analyze $B^- \to μ^- \barν_μ$, $\bar{B}^0 \to π^+ μ^-\barν_μ$, and $B^- \to ρ^0 μ^- \barν_μ$ decays using the data on binned branching fractions recently measured by Belle II Collaboration for the semileptonic modes. We extend the low-energy Hamiltonian governing $b \to u \ell \barν_\ell$ transit