New Physics in Bs-Bsbar Mixing

Seungwon Baek (Korea U)

KISTISep 29, 2010

Work in progress with A. Alok, D. London

Outline

• Introduction

• D0 anomaly and NP in Bs-Bsbar mixing

• Non-universal Z’ model

• Flavor changing Z model with vector-like b’

• Conclusions

B physics in the LHC era

• The SM CKM paradigm has been strongly supported in B, D, and K decays.

• Several rare decays sensitive to NP also support the SM: ΔMd, ΔMs, B→Xsγ, εK, …

• However, ν-oscillations, evidence for DM, the hierarchy problem of the SM suggests NP, hopefully at TeV scale

• Also the B-physics experiments are getting more precise …

• sin2β measurements involving b→s penguins are ~2σ different from S(B→J/ψ KS).

Lunghi, Soni (2009)

●

● Forward-backward asymmetry in

http://www.kek.jp/intra-e/press/2009/BellePress14e.html

deviates from the

SM by 2.2σ●

HFAG (2008)

• However, CDF data shows improved agreement with the SM.

M. Heck, SUSY10

• All these deviations are in b→s transitions

• These will be much more precisely measured at LHCb– Bs→μ+μ-

– .

–

–

D0 like-sign dimuon charge asymmetry

• With 6.1 fb-1 data, D0 measured

:

difference

D0 like-sign dimuon charge asymmetry

• “Wrong sign” charge asymmetry (CPV in mixing)

2.5σ difference

Bs-Bsbar mixing• Mass eigenstates in terms of flavor eigenstates:

• Time evolution:

• Mass and width difference:

NP in Bs-Bsbar mixingU. Nierste, SUSY10

• If NP only in M12s,

• then, imposing from ,

???

NP both in M12s and M12

d ?

U. Nierste, SUSY10

NP both in M12s and M12

d ?

U. Nierste, SUSY10

NP both in M12s and M12

d ?

U. Nierste, SUSY10

Not enough to fully explain the D0 dimuon asymmetry.

Mixing induced CPA in B-decay

I, Yu, KIAS workshop (2010)

Mixing induced CPA in B-decay

• Indirect CPA

• Exp

• SM

NP in Γ12s

• NP in can solve the problem !

• The SM tree amplitude

b→s c cbar is

λ2-suppressed.

• The b→s τ τ vertex is

weakly constrained.

• With NP in the decay b→s f fbar …

• NP in b→s c cbar helps explain CPV in both

and Chiang et al 2009

• No more

Non-universal Z’ model

• Tree-level FCNC

• M12 Γ12

M12 and Γ12 in the SM

• M12

• Γ12

M12 and Γ12 in the Z’ model

• M12

• Γ12(Z’): considered c, τ-loop only, can compete with the SM when

Constraints on Z’ FCNC model

• We imposed

)/(

%5)(

%5)(

sCP

s

s

s

KJBS

BB

XBB

L couplings only

• After imposing constraints

L,R couplings

bscc operator

Flavor changing Z with VL b’

• Introduce vector-like isosinglet b’

• 4x4 down-quark mass matrix

• 3x4 “CKM” matrix V

• U≡V†V≠1 → Z-mediated FCNC at tree-level

Constrains on the NP coupling

• B(B→Xsμμ) sensitivity

– 1<q2<6 (GeV2): dominated by photon

– 7<q2<12: dominated by charm resonances

– 14<q2<mb2 : dominated by Z, W

• We use the high q2 data to constrain Z FCNC model

Constrains on the NP coupling

FC Z contributions to asl, Sψϕ,△Γs

Cannot explain 1σ of asl, Sψϕ. But enhancement by factor ~40 in asl ispossible. Sψϕ: 0.040.1

Conclusions

• Explained semileptonic charge asymmetry

as well as ,

• In non-universal Z´-model, all the three observables can be accommodated with non-standard operators

• In FC Z-model with VL b´, marginal

but cannot explain 1σ of