Transcript B 0
Time-Dependent
CP
violation
_
in bgsqq and bgsg decays
Lake Louise Winter Institute
Feb.21, 2005
Yutaka Ushiroda (KEK)
Outline
• Introduction
– Time-Dependent CP asymmetry (TCPV)
– Belle & KEKB
• Results
– TCPV in charmonium modes
– TCPV in hadronic bgs penguins
– TCPV in radiative bgs penguin
• Summary
b c cs
b sq q
b sg
Time-Dependent CP violation (TCPV)
fc
B0
mixing
=
mixing
p
B0
fc
B0
p
B0
Time dependent amplitudes are different
because of the KM phase
t
B
B
Bd t fCP Bd t fCP
AC P
0
0
d
t
fCP
0
0
d
t
S sin m t A cos m t
Mixing-induced timedependent CPV
Direct CPV
fCP
b c cs
_
B0
_
d
Vtd
w
b
_
t
t
_
b
w
d
V*td
_
_
B0
B0
b
w
d
Mixing (f1) + Decay w/o KM phase
S f sin 2f1 ,
A0
f : C P eigenvalue
In tree, no room that a NP steps in
g SM anchor point
c
c
_
s
d
J/Y
K0
f1
b sq q
_
B0
_
d
Vtd
w
b
_
t
t
_
_
w
b
b
t
w
B0
d
B0
_
g
d
V*td
Extra CPV phase
" sin 2f1 " (NP)
sin 2f1 0.73
Ab sq q Ab c cs 0
_
b _
~
bR
d
f, h’...
s
s
_
s
d
K0
~
g
g
_
_ s
s~R
s
_
s
d
Experimental technique
m+ J/Y
mKS
_
B0
(4S)
electron
(8GeV)
B1
positron
(3.5GeV)
nm
0
fCP
p-
D
B2
p
m+
B0
z ~ 200mm t z
g c
+
K
Flavor tag
KEKB accelerator
3.5 GeV e X 8.0 GeV e
crossing angle = 11 mrad.
Mt. Tsukuba
Belle
KEKB
Belle
~1 km in diameter
L p ea k
1 .5 1 0 cm
3 6 0 fb
Ldt
34
# B B day
2
s
1
1
1 10
6
Results based on 140fb-1 or 253fb-1
Belle Detector K/p separation
g, p0 reconstruction
e+-, KL identification
Electromagnetic Calorimeter
CsI(Tl) 16X0
Aerogel Cherenkov Counter
n = 1.015~1.030
3.5 GeV e+
TOF counter
K/p separation
8.0 GeV e-
charged particle tracking
Central Drift Chamber
momentum, dE/dx
50-layers + He/C2H6
B vertex
Si Vertex Detector
4-layer DSSD
Muon / KL identification
KL m detector
14/15 layer RPC+Fe
b c cs
sin2f1 result
hep-ex/0408111
qCP=+1
qCP=-1
poor flavor tag
good flavor tag
152 10 B B
6
g 4347 signal events
sin 2f1 0.728 0.056 0.023
b sq q
_
275M BB
B0gfK0
S = 0.73
fit
Nsig = 13914
purity = 0.63
Events/(50MeV/c)
Poor tag
Nsig=3615
purity = 0.17
fK0
Good tag
~1.9s away
sig + bkg_sum
bkg_sum
sig + B-bkg
B-bkg
" sin 2f1 " 0.06 0.33 0.09
A 0.08 0.22 0.09
[hep-ex/0409049]
_
275M BB
Nsig = 31 7
purity = 0.56
B 0 gw K S
S = 0.73
fit
Raw Asymmetry
b sq q
Good tag
" sin 2f1 " 0.75 0.64
0.13
0.16
A 0.26 0.48 0.15
[hep-ex/0409049]
~0.0s away
b sq q
Raw Asymmetry
_
275M BB
B0gKSKSKS
S = 0.73
fit
Good tag
Nsig = 7210 3pp168 2pp,1p0p08813
Purity = 0.563pp0.40 2pp,1p0p0
" sin 2f1 " 1.26 0.68 0.18
A 0.54 0.34 0.08
[hep-ex/0409049]
~2.8s away
b sq q
_
275M BB
B0gh’KS
purity = 0.61
Raw Asymmetry
Nsig = 512 27
S = 0.73
fit
Good tag
" sin 2f1 " 0.65 0.18 0.04
A 0.19 0.11 0.05
[hep-ex/0409049]
~0.4s away
b sq q
_
275M BB
B0gKKKS
Mixture of CP even/odd
f 1
1.03 0.15 0.05
Nsig = 399 28
purity = 0.56
Raw Asymmetry
[PRL 91, 261602 (2003)]
S = 0.73
fit
Good tag
" sin 2f1 " 0.49 0.18 0.04
A 0.08 0.12 0.07
[hep-ex/0409049]
~0.9s
b sq q
B0gKSp0
high LHR only
Raw Asymmetry
_
275M BB
S = 0.73
fit
Good tag
Nsig = 16816 (high LHR) 83 16 (low LHR) 251 24
purity = 0.55 (high LHR), 0.17 (low LHR)
" sin 2f1 " 0.30 0.59 0.11
A 0.12 0.20 0.07
[hep-ex/0409049]
~0.7s
b sq q
B0gf0(980)KS
Nsig = 94 14
purity = 0.53
Raw Asymmetry
_
275M BB
S = 0.73
fit
Good tag
" sin 2f1 " 0.47 0.41 0.08
A 0.39 0.27 0.08
[hep-ex/0409049]
~2.9s
“sin2f1” from hadronic bgs penguins
" sin 2 f1 ( b sq q ) " 0.39 0.11
B elle
sin 2f1 ( b c cs ) 0.726 0.037
W . A.
~2.7s
w/o theory error
Deviation from SM expectation !?
b sg
_
B0
_
d
Vtd
w
b
_
t
t
g
_
b
w
d
V*td
B0
B0
_
w
_
b
d
t
s
d
K0
Introduction
AGS [Phys.Rev.Lett. 79, 185 (1997)]
TCPV in B0gM0g decay
M0 : self-conjugate state (K*0(gKSp0), K1(gKSr0))
g : polarized in the SM. Carries the flavor information.
b
sg L
ms
mb
b
sg R
Due to g, the final state is
(almost) flavor specific
(Helicity flip)
S CP
2ms
mb
sin 2f1
4%
~10% according to B.Grinstein, Y.Grossman,
Z.Ligeti, D.Pirjol [PRD 71, 011504 (2005)]
A large CPV
New Physics
An effect that unpolarizes the g
B0gK*0(KSp0)g
_
275M BB
S=0
fit
Poor tag
Nsig=57 9
purity 0.65
Good tag
S 0.79
A0
0.63
0.09
0.50
( fixed )
[hep-ex/0409049]
Extended AGS (AGHS)
AGHS [hep-ph/0410036]
TCPV in B0gP0Q0g decay
P0,Q0: self-conjugate spin-0 neutral particle (KSp0,KSh))
K*(892)
K2*(1430)
57 9
105 14
_
275M BB
B0gKSp0g
S=0
fit
Poor tag
Nsig=105 14
purity 0.50
S 0.58
MK
Sp
0
1.8 G eV
0.46
0.11
0.38
A 0.03 0.34 0.11
[hep-ex/0410036]
Good tag
Summary
_
TCPV in b g ccs
sin 2f1 0.728 0.056 0.023
We know well about SM
TCPV in hadronic b g s penguins
2.7s away from SM expectations with all the
Belle results combined
" sin 2f " 0.39 0.11
1
TCPV in radiative b g s penguins
SM prediction is S~A~0
measured with B0 g Ksp0g (M(KSp0)<1.8GeV)
consistent with 0
0.46
S 0.58
0.11
0.38
A 0.03 0.34 0.11