cp violation in neutral b meson system
DESCRIPTION
CP Violation in Neutral B Meson System. J ingsheng Li Apr 16, 2007 Presentation for Intro. Exp. Part. Course. O utline. CKM Matrix CP Violation in B Meson Decay Detector Design and Data Selection Event Reconstruction Result Conclusion. CKM M atrix. - PowerPoint PPT PresentationTRANSCRIPT
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CP Violation in Neutral B Meson System
CP Violation in Neutral B Meson System
Jingsheng Li
Apr 16, 2007
Presentation for Intro. Exp. Part. Course
Jingsheng Li
Apr 16, 2007
Presentation for Intro. Exp. Part. Course
2
Outline
CKM Matrix CP Violation in B Meson Decay Detector Design and Data Selection Event Reconstruction Result Conclusion
3
CKM Matrix
Quark Mixing, SU(2)U(1) repr.
V=V1V2V3
CP Violation due to angle
€
L = U Lγ μ DL = u c t ( )γ μ (1+ γ 5)V
d
s
b
⎛
⎝
⎜ ⎜ ⎜
⎞
⎠
⎟ ⎟ ⎟
€
V =
1 0 0
0 c2 −s2
0 s2 c2
⎛
⎝
⎜ ⎜ ⎜
⎞
⎠
⎟ ⎟ ⎟
c1 s1 0
−s1 c1 0
0 0 e iδ
⎛
⎝
⎜ ⎜ ⎜
⎞
⎠
⎟ ⎟ ⎟
1 0 0
0 c3 s3
0 −s3 c3
⎛
⎝
⎜ ⎜ ⎜
⎞
⎠
⎟ ⎟ ⎟€
where DL = V
d
s
b
⎛
⎝
⎜ ⎜ ⎜
⎞
⎠
⎟ ⎟ ⎟L
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CKM Matrix continued
€
VCKM =
Vud Vus Vub
Vcd Vcs Vcb
Vtd Vts Vtb
⎛
⎝
⎜ ⎜ ⎜
⎞
⎠
⎟ ⎟ ⎟=
1− λ2 /2 λ Aλ3(ρ − iη )
−λ 1− λ2 /2 Aλ2
Aλ3(1− ρ − iη ) −Aλ2 1
⎛
⎝
⎜ ⎜ ⎜
⎞
⎠
⎟ ⎟ ⎟
€
VudVub* + VcdVcb
* + VtdVtb* = 0
B decay
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B Decay
€
B0 → J /ψ +
€
l + l€
2π
3π
€
K 0
€
b → c + W +* → c + c + s
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CP Violation in B Decay Indirect CP Violation
Direct CP Violation Interference between
channels (to deg ’)
€
BL = B1 + εB2
BS = B1 + εB2
⎧ ⎨ ⎩
€
η00 ≠ 0;η +− ≠ 0
€
η00 ≠ η +− ;φ00 ≠ φ+−
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B Decay in Belle and BABAR
PEP-IILum: 31033/cm2se+/e-:3.1GeV/9.0GeV=0.56
€
Υ(4S)
€
Btag
€
BCP
€
l±
€
K ±
€
D*
€
π ±
CP Eigenstate€
BR ≈10−4
Low momentum
€
l±
€
π ±
€
π 0
e+ e-
Flavor tagz
z/(c)=t
€
Btagged
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BaBar Detector
9GeV
3.1GeV
9
Belle Detector
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Comparison
Belle BaBarBeam Asy. 8.0GeV/3.5GeV
=0.425, 22mrad
9.0GeV/3.1GeV
=0.56, head on
Vetices SVD 3ly SVT 5lyCharged Ptc CDC DCH
Ptc ID CDC, ACC, TOF DIRC
EM shower ECL EMC
, KL RPC IFR
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CP Violation Parameter Decay modes:
Distribution Asymmetry €
J /ψKS0
€
ψ(2S)KS0
€
χclKS0
€
J /ψKL0
€
J /ψK*0
€
KS0π 0
€
f±(Δt) =e
−|Δt | /τB0
2τB 0 (1+ | λ |2)
×1+ | λ |2
2± Imλ sin(Δm
B 0Δt) m1− | λ |2
2cos(Δm
B 0Δt) ⎡
⎣ ⎢
⎤
⎦ ⎥
€
ACP (Δt) ≡f+(Δt) − f−(Δt)
f+(Δt) + f−(Δt)= −η f sin2β sin(Δm
B 0Δt)
ηf= -1 +1-1 -1 0.650.07
€
λ =η f e−2iβ
€
=arg[−VcdVcb* /VtdVtb
* ]
angular mixing
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Event Reconstruction Event Selection
Flavor Tagging Total events 32106
Full BCP <1000
Fitting
€
E = Ebeamcm − EB
cm < 3σ ~ 30MeV
€
mES = (Ebeamcm )2 − ( pB
cm )2 > 5.2GeV
€
BCP
€
J /ψ → l+l−
€
2.95 ≤ me +e − ≤ 3.14GeV
€
KS0 → π +π −
€
489 < mπ +π − < 507MeV
€
KS0 → π 0π 0
€
800MeV < m2π
13
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BABAR Result
Sin2=0.590.14(stat) 0.05(syst)
At 4 level |λ|=0.930.09(stat)
0.03(syst)
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Belle Result
sin2=0.990.14(stat) 0.06(syst)
At 6 level
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Conclusion
(Indirect) CP Violation at 4 levelNow sin2=0.6850.032
Direct CP Violation in
Precise Measurement for SMStay Tuned for New Physics
(Indirect) CP Violation at 4 levelNow sin2=0.6850.032
Direct CP Violation in
Precise Measurement for SMStay Tuned for New Physics
€
B → K +π −
€
AK +π − =
A K −π + / A
K +π − −1
A K −π + / A
K +π − +1= −0.115 ± 0.018
(2005)