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 ,
A0
 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
qCP=+1
qCP=-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 = 13914
purity = 0.63
Events/(50MeV/c)
Poor tag
Nsig=3615
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 = 7210 3pp168 2pp,1p0p08813
Purity = 0.563pp0.40 2pp,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
B0gKKKS
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 = 16816 (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
A0
 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