Recently, several discrepancies at the level of (2–3)σ have been observed in the decay processes mediated by flavour changing neutral current (FCNC) transitions b → sℓ ⁺ ℓ ⁻, which may be considered as the smoking-gun signal of new physics (NP). These intriguing hints of NP have attracted a lot of attention and many attempts are being made to find the possible NP signature in other related processes, which are mediated through the same quark-level transitions. In this work, we perform a comprehensive analysis of the FCNC decays of the B meson to axial vector mesons K ₁(1270) and K ₁(1400), which are an admixture of the 1³ P ₁ and 1¹ P ₁ states K _1A and K _1B , in a model independent framework. Using the B → K ₁ form factors evaluated in the light cone sum rule approach, we investigate the rare exclusive semileptonic decays B → K ₁(1270)μ ⁺ μ ⁻ and B → K ₁(1400)μ ⁺ μ ⁻. Considering all the possible relevant operators for b → sℓ ⁺ ℓ ⁻ transitions, we study their effects on various observables such as branching fractions, the lepton flavor universality violating ratio , forward–backward asymmetries, and lepton polarization asymmetries of these processes. These results will not only enhance the theoretical understanding of the mixing angle but also serve as a good tool for probing NP.

最近，在由风味变化中性电流 (FCNC) 跃迁b → sℓ ⁺ ℓ ⁻介导的衰变过程中观察到了 (2-3) σ水平的几个差异，这可以被认为是新产品的吸烟枪信号。物理学（NP）。这些有趣的 NP 提示引起了很多关注，并且正在尝试在其他相关过程中寻找可能的 NP 特征，这些过程是通过相同的夸克能级跃迁介导的。在这项工作中，我们对B介子的 FCNC 衰减到轴向矢量介子K ₁ (1270) 和K ₁ (1400)进行了综合分析，它们是 1 ³ P ₁和1 ¹ P ₁状态K _{1 A} 和K _{1 B} 在模型独立框架中。使用在光锥和规则方法中评估的B → K ₁形状因子，我们研究了罕见的排他性半轻衰变B → K ₁ (1270) μ ⁺ μ ^-和B → K ₁ (1400) μ ⁺ μ ^-。考虑b 的所有可能的相关运算符→sℓ ⁺ ℓ ⁻跃迁，我们研究了它们对各种可观察量的影响，例如分支分数、轻子风味普遍性违反比率、前后不对称性和这些过程的轻子极化不对称性。这些结果不仅将增强对混合角的理论理解，而且可以作为探测 NP 的好工具。