2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/204192It has been known that there exists a disagreement emerged between the determination of $|V_{ub}|$ from inclusive $B \to X_u\ellν$ decays and exclusive $B \to π\ellν$ decays. In order to solve the mismatch, we investigate the left-right (LR) mixing effects, denoted by $ξ_u$, in leptonic and semileptonic $b \to u$ decays. We find that the new interactions $(V+A)\times (V-A)$ induced via the LR mixing can explain the mismatch between the values of $|V_{ub}|$ if Re$(ξ_{u})=-(0.14 \pm 0.12)$. Furthermore, we also find that the LR mixing effects can enhance the branching fractions for $B \to τν$ and $B \to ρ\ellν$ decays by 30% and 17%, respectively, while reducing the branching fraction for $B \to γ\ellν$ decays by 18%.11 pages, 6 eps figuresHigh Energy Physics - Phenomenologytext