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arXiv 2409.09349hep-ph
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微扰QCD方法下准两体B^{0}\rightarrow T(ππ, K\bar{K},πη)衰变的研究

Study of quasi-two-body B^{0}\rightarrow T(ππ, K\bar{K},πη) decays in perturbative QCD approach

Lun-Lian Mu, Xian-Qiao Yu

AI总结:

本研究用微扰QCD方法计算B^{0}到含张量、标量介子的准两体衰变的分支比与直接CP不对称性,验证部分结果与实验吻合,为理解介子结构性质提供理论依据。

摘要:

本研究采用微扰QCD方法计算了三体衰变B^{0}\rightarrow T(ππ, K\bar{K},πη)的CP平均分支比和直接CP破坏不对称性,其中T代表张量介子a_{2}(1320)、K^{*}_{2}(1430)、f_{2}(1270)和f^{'}_{2}(1525),次级衰变分支为f_{0}(980)\rightarrow ππ、K\bar{K},f_{0}(500)\rightarrow ππ,a_{0}(980)\rightarrow K\bar{K}、πη。我们得到以下结果:(a) 当θ=135°时,计算得到B^{0} \rightarrow K^{*}_{2}(1430)f_{0}(980)[ \rightarrow π^ {+}π^{-}]的分支比为4.30\times10^{-6},随后在窄宽度近似下提取出B^{0} \rightarrow K^{*}_{2}(1430)f_{0}(980)衰变的分支比为8.78\times10^{-6},与当前实验数据吻合良好。(b) 所考虑衰变模式的衰变率通常在10^{-8}到10^{-5}量级。(c) 分支比对θ敏感,对ϕ则不敏感。ϕ的数值很小,因此除了一些涉及f^{'}_{2}(1525)的衰变外,衰变分支比仅有微小变化。(d) θ和ϕ可使纯企鹅过程的直接CP不对称性发生显著变化,使其不为0。(e) 我们计算了相对部分衰变宽度Γ(a_{0} \rightarrow K\overline{K})/Γ(a_{0} \rightarrow πη)以及比值{\cal B}(f_{0} \rightarrow K^{+}K^{-})/{\cal B}(f_{0} \rightarrow π^{+}π^{-}),结果与现有实验值一致。本研究结果有助于理解标量介子的内部结构和张量介子的性质,可通过未来实验进行检验。

英文摘要:

In this study, we calculate the CP-averaged branching ratios and the direct CP-violating asymmetries of the three body decays B^{0}\rightarrow T(ππ, K\bar{K},πη) in the perturbative QCD approach, where T denotes tensor mesons a_{2}(1320), K^{*}_{2}(1430), f_{2}(1270) and f^{'}_{2}(1525), and the daughter branching is f_{0}(980)\rightarrow ππ, K\bar{K},f_{0}(500)\rightarrow ππ, a_{0}(980)\rightarrow K\bar{K}, πη. We found the following (a) With θ=135^{\circ}, we evaluate the branching fractions of B^{0} \rightarrow K^{*}_{2}(1430)f_{0}(980)[ \rightarrow π^ {+}π^{-}] to be 4.30\times10^{-6},then under the narrow-width approximation we extract the branching fraction of the decay B^{0} \rightarrow K^{*}_{2}(1430)f_{0}(980) to be 8.78\times10^{-6},which is consistent with the current experimental data well. (b) The decay rates for the considered decay modes are generally in the order of 10^{-8} to 10^{-5}. (c) The branching fractions are sensitive to the θ, and the opposite is true for ϕ. The ϕis really small, so the decay branching ratio has only little change, except for some decays involving f^{'}_{2}(1525). (d) The θand ϕcan bring remarkable change to the direct CP asymmetries of pure penguin processes so that it is not 0. (e) We calculate the relative partial decay widths Γ(a_{0} \rightarrow K\overline{K})/Γ(a_{0} \rightarrow πη) and the ratio {\cal B}(f_{0} \rightarrow K^{+}K^{-})/{\cal B}(f_{0} \rightarrow π^{+}π^{-}), which are in agreement with the existing experimental values. Our results can help one to understand the internal structure of scalar mesons and the nature of tensor mesons and can be tested by future experiments.

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