ICFP05, NCU1 B → Kπ decays and new physics in the EW-penguin sector Yu, Chaehyun ( Yonsei University) October 6, 2005 In Collaboration with C.S. Kim, S. Oh J.H. Jeon, C.S. Kim, Jake Lee

ICFP05, NCU2 Outline  puzzle  Numerical analysis  Flavor changing model and  Conclusion

ICFP05, NCU3 B → Kπ decays  4 decay channels ( and anti-particle decay channels)  All branching ratios are well measured within 10% errors.  Direct CP asymmetry in B → K + π - has been observed at the 5.7σ level.  Other CP asymmetries have rather large errors.  Conventional SM prediction is not consistent with the current data.

ICFP05, NCU4 All observables are measured.

ICFP05, NCU5 SM : Puzzle in Branching Ratios a considtent pattern by CLEO, BABAR, BELLE

ICFP05, NCU6 Puzzle in Direct CP Asymmetry SM : Large strong phases are required.

ICFP05, NCU7 Puzzle in Indirect CP Asymmetry In

ICFP05, NCU8

9 All data 4 BRs only Large r c Large r EW

ICFP05, NCU10 Best fit values are Large r c Large r EW Charnng, Li; He, McKellar; Wu, Zhou; Mishima, Yoshikawa;

ICFP05, NCU11 Why r C is so large? In the conventional hierarchy (r C = 0.02), But, experimental data show 1.32σ deviation. This may indicate that the subleading terms including r C and r EW play an important role.

ICFP05, NCU12 The parameter r c is sensitive to the observable S K s  Sensitivity check

ICFP05, NCU13 New Physics in EW penguin sector ? Large Enhancement in r C is very difficult in the SM and in New Physics because it is related to the color-allowed tree amplitude. Small r C solution can be relieved by new physics with weak phase in EW penguin sector. cf. Baek, Hamel, London, Datta, Suprun, PRD71, (2005)

ICFP05, NCU14 Leptophobic Z΄ Model

ICFP05, NCU15 Z-mediated vs. Z΄-mediated FCNC Possible scenarios in GUT model (E 6 model). Z-mediated FCNC are constrained by Originally leptophobic Z΄ model was introduced to explain R b -R c puzzle at LEP → Now, original motivation disappears. Constraints on leptophobic Z΄ model may be weaker than other Z΄- or Z-mediated FCNC models. However, it still remains as a viable candidate of new physics.

ICFP05, NCU16 Brief review of leptophobic Z΄ model SU(2) L xU(1) Y xU(1)΄ : U(1)΄ arise from the breaking chain with Q΄=Q ψ cos θ – Q χ cos θ, where θ is the usual E 6 mixing angle Leroux, London, PLB526,97(2002)

ICFP05, NCU17 The most general SU(2) L xU(1) Y xU(1)΄ invariant Lagrangian include a kinetic mixing term between U(1) Y and U(1)΄ gauge bosons: With the non-unitarity transformation Z΄-fermion interaction term can be written Leptophobic Z΄ if tan θ = √ 3/5 and δ = -1/3 for conventional embedding.

ICFP05, NCU18 Parametrize Z΄- mediated FCNC coupling as Z΄ does not couple to SM neutrino because it is leptophobic. However, it does couple to the right-handed neutrino (ν c or S c ). Tree level FCNC in B decays

ICFP05, NCU19 Leptophobic Z΄ model and B decays New physics in EW penguin sector? – where can we confirm it? EW penguin dominant processes is most prominent for such NP. If new physics is leptophobic, we can resort to Z΄ mass bound (CDF)

ICFP05, NCU20 Cf. from inclusive decay b →s νν at ALEPH

ICFP05, NCU21

ICFP05, NCU22 Conclusion Current data implies large enhancements in r C and r EW. New physics in EW penguin sector may solve B → Kπ puzzle. But, the evidence for new physics is not decisive. EW penguin dominant processes can serve as a probe of new physics in the EW penguin sector.

ICFP05, NCU23

ICFP05, NCU24 Theoretical Expectation Charming Penguins

ICFP05, NCU25 SM : Enhancements in sub-dominant components can lead to a sizable deviation in R c -R n.

ICFP05, NCU26 SM :

ICFP05, NCU27 NLO in PQCD Recently the NLO calculation including vertex correction, quark loop, and magnetic penguin in PQCD has been done (Li, Mishima, Sanda, hep-ph/ )

ICFP05, NCU28 Although BRs and direct CP asymmetries are explained well in NLO in PQCD, the indirect CP asymmetries are inconsistent with current data, but almost same to the conventional SM prediction.