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New Effects on Rare B Decays

New Effects on Rare B Decays. 2 nd Semester in 2005. 1. (leptophobic)Z’-mediated FCNCs 2. Rare B decays in SM 3. New effects on Rare B decays. (Leptophobic)Z’-mediated FCNCs. Jonghun Jeon (2005.10.10). Outline. FCNCs Z-mediated FCNCs Z’-mediated FCNCs

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New Effects on Rare B Decays

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  1. New Effects on Rare B Decays 2nd Semester in 2005

  2. 1. (leptophobic)Z’-mediated FCNCs 2. Rare B decays in SM 3. New effects on Rare B decays

  3. (Leptophobic)Z’-mediated FCNCs Jonghun Jeon (2005.10.10)

  4. Outline • FCNCs • Z-mediated FCNCs • Z’-mediated FCNCs • Leptophobic Z’-mediated FCNCs

  5. FCNCs in SM T Tree level • Not exist!!! (GIM) P 1-loop level • Possible! • Strongly suppressed !!! • NP???

  6. FCNCs at the tree level ? Yes !!! • Z-mediated FCNCs Y.Nir, D.Silverman, PRD42,1477(1990) • Z’-mediated FCNCs E.Nardi, PRD48,1240(1993) E.Nardi et al, NPB409,69(1993) Where ??? Low Energy Limit of E6 GUT !!!

  7. Z-mediated FCNCs talked by Prof.Kim in the last semester • Vector-like-(isosinglet)-Downquark : h ⇒ Unitarity violation of the three-generation CKM matrix

  8. Z-mediated FCNCs talked by Prof.Kim in the last semester • To understand how Z-mediated FCNCs arise Vij : 3x4 submatrix of 4x4 unitary matrix (K) ( 6 angles & 3 phase !!! → CPV !!!) • Non-vanishing non-diagonal elements of Upq allow Z-mediated FCNCs !!!

  9. Z’-mediated FCNCs • Additional U(1)’ arise from the breaking chain with Q’=Qψcosθ – Qχsinθ where θ is the usual E6 mixing angle Note!!! • “ Q’ ≠ 0 “ : ⇒ Z’-mediated FCNCs ( l & q have different U(1)’ quantum numbers) • “ Q’ = 0 “ : ⇒ leptophobia ! ( Not couple to the chared ptls) ⇒ No value of θ !!!

  10. Leptophobic Z´ Model K.S.Babu,C.Kolda,J.March-Russell (PRD54,4635)(1996) • The most general SU(2)LXU(1)YXU(1)’ invariant Lagrangian includea kinetic mixing term between the U(1)Y and U(1)’ :leptophobia!!! How ??? • To remove the off-diagonal coupling of the and ⇒ with the non-unitarity transformation

  11. Leptophobic Z´ Model K.S.Babu,C.Kolda,J.March-Russell (PRD54,4635)(1996) • The couplings of the physical gauge bosons to fermion can be written as

  12. Leptophobic Z´ Model K.S.Babu,C.Kolda,J.March-Russell (PRD54,4635)(1996) • The Z’-fermion interaction term can be written as Note!!! The Z’-fermion coupling is no longer proportional to Q’ ⇒Two unknown parameter:θandδ ⇒ Leptophobia !!!

  13. Leptophobic Z´ Model K.Leroux, D.London (PLB526,97) • Leptophobia !!! • Choice !!! Note!!! However other embeddings are possible !!!

  14. Leptophobic Z´ Model K.Leroux, D.London (PLB526,97) Other embeddings !!! • First, switch the quantum numbers of L and H !!! ( L & H have the same SU(2)LXU(1)Y Q.Ns)

  15. Leptophobic Z´ Model K.Leroux, D.London (PLB526,97) Other embeddings !!! • Second, singlets under SU(3)C and SU(2)L !!! ( eC can be assigned to any one of these three)

  16. Leptophobic Z´ Model K.Leroux, D.London (PLB526,97) Other embeddings !!! • Second, singlets under SU(3)C and SU(2)L !!! ( eC can be assigned to any one of these three) Note!!! All three states have Notthe same electric charge !!! ⇒ Need different definitions of the charge generator !!!

  17. Leptophobic Z´ Model K.Leroux, D.London (PLB526,97) • There are thus a total of six choices for possible embeddings of the charged leptons in the 27 representation of E6 !!! ⇒ Leptophobic Z’ can be produced for any of these !!! • Z’-mediated FCNCs can occur if the d,s and b mix with the h. However , mixing of the dL , sL and bL with hL will lead to Z-mediated FCNCs among the ordinary fermions. ⇒ Z-mediated FCNCs will always dominate over any Z´-mediated FCNCs !!! Note!!! If we just consider mixing of the dR , sR and bR with hR ⇒ Z'-mediated FCNCs exist only !!!

  18. (Leptophbic) Z´-mediated FCNCs K.Leroux, D.London (PLB526,97) When ??? Q‘(dc) ≠ Q‘(hc) Where ???

  19. (Leptophobic) Z´-mediated FCNCs K.Leroux, D.London (PLB526,97) • The contrbution of Z’-mediated FCNCs to Parameterize !!! • quark • neutrino • Two unknown parameters !!!

  20. (Leptophobic) Z´-mediated FCNCs K.Leroux, D.London (PLB526,97) • The contrbution of Z’-mediated FCNCs to where Fps ≈ 0.5

  21. Summary • In SM , FCNCs are forbbiden!!! • Z-mediated FCNCs can be occurred through the mixing of ordinary ptls with exotic ptls • Z‘-mediated FCNCs can be occurred through themixing of the ordinary particles having additional U(1)’ gauge quantum numbers • Leptophobic Z’ can couple to R-handed quarks and neutrinos • The constraints on the flavor-changing coupling UZ‘ are relatively weak. (Because the Z‘ does not couple to charged leptons )

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