Study of scalar meson a_0(1450) from B \to a_0(1450)K^* Decays

TL;DR

This paper investigates the decay processes involving the scalar meson a_0(1450) in B meson decays, comparing two quark model scenarios using perturbative QCD, and predicts branching ratios and CP asymmetries to help distinguish the meson's nature.

Contribution

It provides a detailed analysis of B to a_0(1450)K* decays under two different quark model scenarios using perturbative QCD, offering predictions to differentiate the meson structure.

Findings

Branching ratios are larger in scenario II by about an order of magnitude.

The decay B^-→a_0^0(1450)K*- has a branching ratio around 10^-6 in scenario II.

Predicted direct CP asymmetry for B^-→a_0^- (1450)K*^0 is small, only a few percent.

Abstract

In the two-quark model supposition for the meson $a_0(1450)$, which can be viewed as either the first excited state (scenario I) or the lowest lying state (scenario II), the branching ratios and the direct CP-violating asymmetries for decays $B^-\to a^{0}_0(1450)K^{*-}, a^{-}_0(1450)K^{*0}$ and $\bar B^0\to a^{+}_0(1450)K^{*-}, a^{0}_0(1450)\bar K^{*0}$ are studied by employing the perturbative QCD factorization approach. We find the following results: (a) For the decays $B^-\to a^{-}_0(1450)K^{*0}, \bar B^0\to a^{+}_0(1450)K^{*-}, a^{0}_0(1450)\bar K^{*0}$, their branching ratios in scenario II are larger than those in scenario I about one order. So it is easy for the experiments to differentiate between the scenario I and II for the meson $a_0(1450)$. (b)For the decay $B^-\to a^{0}_0(1450)K^{*-}$, due to not receiving the enhancement from the $K^*-$emission factorizable diagrams, its penguin operator contributions are the smallest in scenario II, which makes its branching ratio drop into the order of $10^{-6}$. Even so, its branching ratio in scenario II is still larger than that in scenario I about 2.5 times. (c) Even though our predictions are much larger than those from the QCD factorization results, they are still consistent with each other within the large theoretical errors from the annihilation diagrams. (d) We predict the direct CP- violating asymmetry of the decay $B^-\to a^{-}_0(1450)K^{*0}$ is small and only a few percent.