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Rare B decays in Warped Extra Dimension Model with Custodial Symmetry

Cheng LiTheory Division, IHEP

Collaborate with Cai-Dian Lϋ

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Outline Introduction Effective Hamiltonian and Branching

Ratios Results and Analysis Summary and Outlook

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Motivation

Rare B-decays induced by flavor changing neutral currents provide a valuable search for physics beyond the standard model indirectly.

Randall-Sundrum model, as a realistic model of EW symmetry breaking, provide an ambitious proposal to explain hierarchy between the Planck and EW scale, meanwhile one can naturally generate the hierarchies in the fermion mass spectrum and mixing angle.

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Introduction to the Model

The metric is:

The hierarchy problem is then solved by noting that generic mass scales M in the 5D theory are scaled down to on the IR brane.

The bulk symmetry is:

and the Figure of the Model is

PRL.83,3370(1999)

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We need a Higgs bidoublet and appropriate boundary conditions

JHEP09,064(2009)

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Flavor Structure

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Feynman Diagram for the Process

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Effective Hamiltonian

Integrating out the particles above scale , we arrive at the effective Hamiltonian

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Neutral Current

In this model we have to consider three gauge bosons with the corresponding mass eigenstates , and .

The main results can be briefly summarized as follows: the EW tree level contributions to

observables mediated by the new weak gauge boson .

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Branching Ratios

Important formulae for

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Important formulae for

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Results and Analysis

Forward Backward Asymmetry:

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We have the opposite sign within SM, where the effective Hamiltonian is

7C

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the NP effects in rare B decays are generally small (O(10%)) in the model

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The SuppressionInduced by the Custodial Protection

We have

Taking into account the symmetry breaking effects on the UV brane, the custodial protection mechanism is not exact anymore, but still powerful enough to suppress by two orders of magnitude.

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Summary and Outlook

New physics contributions to rare K and B decay, especially in transitions, are governed by tree level contributions from boson in the warped extra dimension model with custodial symmetry, which is consistent with CDF data and will be test in LHCb.

The rare B decays can be used as a ideal platform for testing physics beyond SM in the LHC era.

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Thank You!