Analysis of semileptonic B → a₁ (1260) ⁻ ν̄_ process within SMEFT framework

Motivated by the prospects of the ongoing B meson experiments, we study the exclusive B → a₁ (1260) ⁻ ν̄_ process within the Standard model effective field theory formalism. The new physics parameters are constrained by using the experimental branching fractions of the (semi)leptonic B → ν̄ and B → (π, ρ, ω) ν̄ processes (where = e, μ, τ) which undergoes b → u ν̄ quark level transitions. We then study a comprehensive angular coefficient analysis of the exclusive B → a₁ (1260) ⁻ ν̄_ process in the Standard model and in the presence of various new physics operators.