New Physics in Bs-Bsbar Mixing Seungwon Baek (Korea U) KISTI Sep 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: ΔM d, ΔM s, B→X s γ, ε K, … 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 K S ). Lunghi, Soni (2009)

● ● Forward-backward asymmetry in

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 – B s →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 mixing U. Nierste, SUSY10

If NP only in M 12 s, then, imposing from, ???

NP both in M 12 s and M 12 d ? U. Nierste, SUSY10

NP both in M 12 s and M 12 d ? U. Nierste, SUSY10

NP both in M 12 s and M 12 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 Γ 12 s NP in can solve the problem ! The SM tree amplitude b→s c cbar is λ 2 -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 M 12 Γ 12

M12 and Γ12 in the SM M 12 Γ 12

M12 and Γ12 in the Z’ model M 12 Γ 12 (Z’): considered c, τ-loop only, can compete with the SM when

Constraints on Z’ FCNC model We imposed

L couplings only After imposing constraints

L,R couplings

b  scc 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→X s μμ) sensitivity – 1<q 2 <6 (GeV 2 ): dominated by photon – 7<q 2 <12: dominated by charm resonances – 14<q 2 <mb 2 : dominated by Z, W We use the high q 2 data to constrain Z FCNC model

Constrains on the NP coupling

FC Z contributions to a sl, S ψ ϕ, △ Γ s Cannot explain 1σ of a sl, S ψ ϕ. But enhancement by factor ~40 in a sl is possible. S ψ ϕ : 0.04  0.1

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