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Using the Bs meson wave function extracted from non-leptonic Bs decays, we reevaluate the rare decays Bs→l+l- γ,(l=e,μ) in the Standard Model, including two kinds of contributions from the magnetic-penguin operator with virtual and real photons. We find that contributions to the exclusive decays from the magnetic-penguin operator b→sγ with real photons, which were regarded as negligible in the previous literature, are large and the branching ratios Bs→l+l-γ are enhanced by a factor of almost 2. With the predicted branching ratios of the order of 10-8, it is expected that these radiative dileptonic decays will be detected in LHC-b and B factories in the near future. 相似文献
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Using the Bs meson wave function extracted from non-leptonic Bs decays, we reevaluate the rare decays Bs→l+l- γ,(l=e,μ) in the Standard Model, including two kinds of contributions from the magnetic-penguin operator with virtual and real photons. We find that contributions to the exclusive decays from the magnetic-penguin operator b→sγ with real photons, which were regarded as negligible in the previous literature, are large and the branching ratios Bs→l+l-γ are enhanced by a factor of almost 2. With the predicted branching ratios of the order of 10-8, it is expected that these radiative dileptonic decays will be detected in LHC-b and B factories in the near future. 相似文献
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The operators of b→sγ, b→sl+l- are usually regarded as being sufficient to describe b→sγγ, b→sl+l-γ with the statement that contributions from diagrams without an effective vertex b→sγ to processes b→sγγ and b→sl+l-γ are negligible. In this work we present a comprehensive analysis of the transition b→sγγ and find that 1) Effects due to off-shell quarks in vertex b→sγ on b→sγγ are large; 2) Contributions from diagrams without an effective vertex b→sγ to b→sγγ are not negligible compared with others; 3) These effects cancel each other out exactly, so the operators of b→sγ can safely be used to describe b→sγγ. 相似文献
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Subject to neutrino experiments, the mixing matrix of ordinary neutrinos can still have small vi-olation from unitarity. We introduce a quasi-unitary matrix to interpret this violation and propose a natural scheme to parameterize it. A quasi-unitary factor △QF is defined to be measured in neutrino oscillation exper-iments and the numerical results show that the improvement in experimental precision may help us figure out the secret of neutrino mixing. 相似文献
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Neutrino oscillation experiments provide the first evidence on non-zero neutrino masses and indicate new physics beyond the standard model. With Majorana neutrinos introduced to acquire tiny neutrino masses, it leads to the existence of more than three neutrino species, implying that the ordinary neutrino mixing matrix is only a part of the whole extended unitary mixing matrix and thus no longer unitary. We give a parameterization for a non-unitary neutrino mixing matrix under seesaw framework and further present a method to test the unitarity of the ordinary neutrino mixing matrix. 相似文献
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