摘要According to the recent experimental data, the time-dependent CP asymmetry SψKS for Bd→KS decay might still be inconsistent with the standard model (SM) expectations. We try to understand the anomaly with a Z' model associated with flavour changing neutral currents (FCNCs) at the tree level. We find that (i) if neglecting the contributions from the right-handed flavour changing coupling BRsb and setting ξLL=ξLR=ξ and ξLL=ξ, ξLR=0, we may obtain 0.01< ξ <0.014, 0.0175< ξ <0.0205, 0.021< ξ <0.0255 and 0.004< ξ <0.008, 0.018< ξ <0.028, 0.042< ξ <0.048 for the Bd→ψ KS decay, respectively; (ii) if considering the contributions coming from BRsb and setting ξLL=ξRL=ξLR=ξRR=ξ and ξLL=ξRL=ξ, ξLR=ξRR=0, we can obtain 0.005< ξ<0.075, 0.0085< ξ<0.0105, 0.011<ξ<0.013 and 0.0125<ξ<0.0177, 0.0224< ξ<0.025. These results are consistent with the constraints and the assumptions in some literature.
Abstract：According to the recent experimental data, the time-dependent CP asymmetry SψKS for Bd→KS decay might still be inconsistent with the standard model (SM) expectations. We try to understand the anomaly with a Z' model associated with flavour changing neutral currents (FCNCs) at the tree level. We find that (i) if neglecting the contributions from the right-handed flavour changing coupling BRsb and setting ξLL=ξLR=ξ and ξLL=ξ, ξLR=0, we may obtain 0.01< ξ <0.014, 0.0175< ξ <0.0205, 0.021< ξ <0.0255 and 0.004< ξ <0.008, 0.018< ξ <0.028, 0.042< ξ <0.048 for the Bd→ψ KS decay, respectively; (ii) if considering the contributions coming from BRsb and setting ξLL=ξRL=ξLR=ξRR=ξ and ξLL=ξRL=ξ, ξLR=ξRR=0, we can obtain 0.005< ξ<0.075, 0.0085< ξ<0.0105, 0.011<ξ<0.013 and 0.0125<ξ<0.0177, 0.0224< ξ<0.025. These results are consistent with the constraints and the assumptions in some literature.
WANG Shuai-Wei;SONG Tai-Ping;LU Gong-Ru;ZHONG Zhi-Guo. Analysis of Bd→ψ KS CP Asymmetry in a Flavour Changing Z' Model[J]. 中国物理快报, 2007, 24(10): 2777-2780.
WANG Shuai-Wei, SONG Tai-Ping, LU Gong-Ru, ZHONG Zhi-Guo. Analysis of Bd→ψ KS CP Asymmetry in a Flavour Changing Z' Model. Chin. Phys. Lett., 2007, 24(10): 2777-2780.
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