| Scalar mesons established in experiments are classified into two nonets:one with masses around 1 GeV and the other around 1.5 GeV.In quark model,there are two different explanations on the structure of the scalar mesons,which are represented by Scenario I(SI for short)and Scenario II(SII for short)in this work.In SI,the nonet near 1 GeV are treated as the lowest lying qq states,while the nonet near 1.5 GeV are the first excited states.In SII,the nonet mesons near 1.5 GeV are treated as qq ground states,while the nonet mesons near 1 GeV are four-quark bound states.In this work we studied the two-body nonleptonic decays of the Bs meson into a strange scalar meson and a strange pseudo-scalar meson,which cover the following processes:Bs0?K0*0K0?K0K0*0?K0*0K-?K+K0*-??k0??K0?k+K-?K-K+.Since there are not any effective method to deal with the four quark states in factorization theories,we only investigate the scalar mesons under the qq structures.In the calculation we employ the perturbative QCD factorization approach.We draw out the Feynman diagrams of all the decays,get the corresponding analytic expressions,and carry out the numerical integrations by writing FORTRAN programs.Our results can be summarized as following.(1)The branching ratios of all the related decays,ranging from 10-6 to 10-4 are obtained,which is hopeful to be observed by the current experiments.The branching ratios of Bs0?K0*0K0 and Bs0?K0*K-are close to each other under SI and SII,which indicate low sensitivity to the scenario different;For Bs0?K0*0K0 and Bs0?K0*K-the branching ratios under S? are about 2 times larger than those under SI,which can be used to distinguish the two scenarios with the help of experiments.(2)The CP violations are also studied,most of which are found to be small,except that for Bs0??-K+,whose values is about 20%.Through some careful analyzation,we found that the ratio of the penguin contribution to tree contribution of this channel is similar to other decays,and the large CP violation is caused the special value of strong phase.The CP violation of the decays with only penguin contribution are zero,for there is no interferences.(3)We carry out an investigation on the ratio of tree and penguin contributions.The penguin contribution,which are loop effects in the standard model,is expected to be small.However,in this research all the tree contributions are doubly CKM suppressed.Compared to the CKM with penguin contributions,the CKM with tree contributions are suppressed by a factor about 1/50.Therefore,the penguin contributions are dominating in these channels.(4)In our results,we estimate three types of errors,which are respectively from the CKM matrix elements,the parameters of wave functions,and the scales.In addition,we also studied a dependencies of the branching ratios and direct CP violation in hope of improving accuracy of this parameter with help of the future experiments.The research work of the subject is helpful for deep understanding of the QCD and factorization theory,investigating the mechanism of the CP violation,researching the structures of scalar mesons and determining the related parameters of the CKM matrix elements. |
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