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