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Test Z’ Model in Annihilation Type Radiative B Decays. Ying Li Yonsei University, Korea Yantai University, China. Based on J. Hua, C.S Kim, Y. Li, arxiv:1002.2531. Outline. Motivation Calculation of in the SM Calculation in the non-universal Z’ model Summary. Motivation.

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## Test Z’ Model in Annihilation Type Radiative B Decays

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**Test Z’ Model in Annihilation Type Radiative B Decays**Ying Li Yonsei University, Korea Yantai University, China Based on J. Hua, C.S Kim, Y. Li, arxiv:1002.2531**Outline**• Motivation • Calculation of in the SM • Calculation in the non-universal Z’ model • Summary**Motivation**• The SM is just an effective theory of a more fundamental one yet to be discovered. • B physics plays an important role in searching for new physics signals. • Additional U(1)’ gauge symmetries and associated Z’ gauge bosons could appear in several well motivated extensions of the SM. • I would like to check the Z’ effect in the annihilation type radiative B decays**Annihilation type radiative B decays play important role in**explaining CP violation and SU(3) asymmetry of BK*gamma, Brho gamma. A. Ali and A. Parkhomenko, arXiv:hep-ph/0610149. S. W. Bosch and G. Buchalla, Nucl. Phys. B 621, 459 (2002) P. Ball, G. W. Jones and R. Zwicky, Phys. Rev. D 75, 054004 (2007) W. Wang, R. H. Li and C. D. Lu, arXiv:0711.0432 [hep-ph]. • Some annihilation type radiative decays, such as B->phi gamma and B->J/psi gamma , have been analyzed in the QCD factorization approach and in the perturbative QCD approach . X. Q. Li, et..al , Eur. Phys. J. C 36, 97 (2004) G. R. Lu, et.al, Eur. Phys. J. C 34, 291 (2004) Y. Li and C. D. Lu, Phys. Rev. D 74, 097502 (2006)**In order to calculate the form factor FV , we need**two-particle light-cone projector for an initial B meson: So we get: With the parameterization: The form factor FV has been defined as:**we write down the helicity amplitudes for these channels as:**We can get the averaged branching ratios as:**Branching Ratios:**CP Asymmetries: The above ratios can not be observed in the current running machines now. If the factories found any signals, we could say that we find the new physics.**Introduction to Z’ Model**• Additional heavy neutral Z’ gauge bosons are amongst the best motivated extensions of the standard model, or its supersymmetric extension . • In particular, they often occur in grand unified theories, superstring theories, and theories with large extra dimensions. • In traditional GUTs, the scale of the Z′mass is arbitrary. However, many researches imply that the Z’ mass should be less than around a TeV. • There is thus both theoretical and experimental motivation for an additional Z’ , most likely in the range 500 GeV - 1 TeV. If true, there should be a good chance to observe it at RUN II at the Tevatron, and certainly at the LHC. • The collider signals of Z’ have been explored by many groups.**The effects of Z ’ in B sector have been investigated by**many groups: • P. Langacker et. al, , Phys. Rev. D 62, 013006 (2000) ; P. Langacker, arXiv:0801.1345; • V. Barger, et. al, Phys. Lett. B 580, 186 (2004) ; V. Barger, et. al, Phys. Lett. B 598, 218 (2004) ; V. Barger, et. al, arXiv:0906.3745 ; V. Barger, et. al, Phys. Rev. D 80, 055008 (2009) ; • K. Cheung, et. al, Phys. Lett. B 652, 285 (2007) ; C. W. Chiang , et. al, JHEP 0608, 075 (2006); • C. H. Chen , et. al, Phys. Rev. D 73, 075003 (2006); C. H. Chen, arXiv:0911.3479 [hep-ph]; • C. W. Chiang, R. H. Li and C. D. Lu, arXiv:0911.2399 [hep-ph]; R. Mohanta and A. K. Giri, Phys. Rev. D 79, 057902 (2009); • Q. Chang, X. Q. Li and Y. D. Yang, JHEP 0905, 056 (2009) Q. Chang, X. Q. Li and Y. D. Yang, arXiv:0907.4408 [hep-ph] ……**Introduction to Z’ Model**• We will consider the model in which the interaction between the Z’ boson and fermions are flavor non-universal for left handed couplings and flavor diagonal for right handed couplings. • In our work, we neglected the mixing between the Z and Z’ and the evolution effect from the high scale Mz’ to the MW scale. • We write the couplings of the Z’ boson to fermions as:**After rotating to the physical basis, FCNCs generally**appear at tree level in both left handed and right handed sectors. Moreover, these couplings may contain CP-violating phases beyond that of the SM. The effective Hamiltonians describing the transition mediated by the Z ’ boson have the form as: with denote the left (right) handed effective Z’ couplings of the quarks i and j at the weak scale.**With the definition:**we can get: Generally, one expects g0/g1~ 1, if both the U(1) gauge groups have the same origin from some grand unified theories, and MZ/MZ0~0.1 for a TeV scale neutral Z ’ boson, which yields y~10−2. However, if assuming a small mixing between Z −Z ’ bosons, the value of y is taken as y~10−3.**It has been shown that the mass difference of Bs −Bs**bar mixing can be explained if . The CP asymmetry anomaly in B->phi K, phi K* can be resolved if . So, we assume that: It is noted that the other Wilson coefficients may also receive contributions from the Z’ boson through renormalization group (RG) evolution.**Summary**• The smallness of these decays in the standard model makes them sensitive probes of flavor physics beyond the standard model. • Within the allowed parameter space, the branching ratios of these decay modes can be enhanced remarkably in the non-universal Z ’ model • These branching ratios are large enough for LHC-b and/or Super B-factories to detect those channels in near future. Moreover, we also predict large CP asymmetries in suitable parameter space. • The observation of these modes could in turn help us to constrain the Z ’ mass within the model.

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