Measurements of and sin(2) in BaBar...ICHEP'04 32ndInternational Conference on High Energy Physics....
Transcript of Measurements of and sin(2) in BaBar...ICHEP'04 32ndInternational Conference on High Energy Physics....
Gianluca Cavoto1
Measurements of and sin(2 ) in BaBar
Gianluca CavotoPrinceton University
Università di Roma La Sapienza
On behalf of theBaBar Collaboration
ICHEP'0432nd International Conference on
High Energy Physics
Gianluca Cavoto2
Angle of t he Unit arit y Triangle
Measure relative phase between Vub and VcbMeasure relative phase between Vub and Vcb
from direct CP asymmetry
Process mediated by both b c and b u amplitudes
Results (all preliminary)
0
(*)
(*)0 0
0 *0 0 0
0
*
, (
[ 3
)
[ ]
]
CP
CP
CPB D K D D K
B
B D K
D K
B D D body
K
K
0 (*)
(*)
0
00 (*)0
,
s
D
Search fo
B D
B D
D
K
r B
sin(2 + ) time dependent CP asymmetry
Updated and new results
Gianluca Cavoto3
f rom direct CP violat ion
Relative size (rB) of B decay amplitudes
Different incarnationsDifferent incarnations
Not well constrained by theory.Larger rB, larger interference, better experimental precision
Relative strong phase ( B) unknown
( )
( )B
A b ur
A b c
Interference when D final state common to both D0 and D0Interference when D final state common to both D0 and D0
BaBar hep-ex/0402024 0.22(90% . .)Br C LBelle hep-ex/0406067
0.100.140.26 0.03 0.04Br
Bi ie e
Gianluca Cavoto4
Gronau London Wyler method
CP modes: small D0 branching ratio
D decays into CP eigenstate D decays into CP eigenstate
Select CP-even and CP-odd final states
Theoreticallyclean, but with 8-foldambiguity
0 02
0
( ) ( )1 2 cos cos
2 ( )CP CP
CP B B B
B D K B D KR r r
B D K
0 0
0 0
( ) ( )2 sin sin
( ) ( )CP CP
CP B B CPCP CP
B D K B D KA r R
B D K B D K
3 observables, 3 unknowns
2)(000 DDDCP
Normalize to D0 decay into flavour state (K- +)Experimentally
Gianluca Cavoto5
Analysis t echniques
Cerenkov angleNo charge confusion. Clear separation D /D
BF(B DK) ~ 10 -4, BF(D f) ~ 10 -2 reconstruct as many f final states as possible BF(B DK) ~ 10 -4, BF(D f) ~ 10 -2 reconstruct as many f final states as possible
dataMC
High reconstruction efficiency
Reject
eventstopological variables
in Neural Network or Fisher discriminant
e e qq
2*2*BbeamES pEm
**beamB EEE
Gianluca Cavoto6
B- D0CP
- yields
D0 background
B+ CP+ B- CP+ B- CP-B+ CP-
NBB=214 106
Combine severalfinal states
NBB=227 106
75 13
18 7
K K 0 76 13SK
15.1 5.8CP34.4 6.9CP
Adding KS , KS
D0CP K -D0
CP K - CP+ ( + -,K+K-) CP- (KS0)
D0CP K* - (K* - KS
-)D0CP K* - (K* - KS
-)
Gianluca Cavoto7
GLW B- D(*)0CP
*)- results
CP
CP
- 0.80 0.14 0.08
0.21 0.17
0.87 0.14 0.06
0.40 0.15 08
0
0
.
.
07C
C
P
P
R
R
A
A
D0CP K -D0
CP K - D0CP K* - (K*- KS
-)D0CP K* - (K*- KS
-)
0.040.1CP- 4
CP
0.33 ( 1.15 0.0.34 0.1 )0 12 ( )
0.76 0.29 0.0
1.77 0.37 0.12
0.09 0.20 0.0
6
6
CP CP CP
CP
A AA
R
A
R
Additional systematic erroron ACP- ( CP even background)
More CP eigenstate finalstates still to be added More statistics needed to constrain More statistics needed to constrain
Loose bound on rB22(1 )CP CP BR R r
From DCPK*2 0.23 0.24Br
0.100.081.09 0.26
0.02 0.24 0.05CP
CP
R
A
D*0 (D0CP
0)K -D*0 (D0CP
0)K -
NBB=214 106 NBB=227 106
NBB=123 106
Gianluca Cavoto8
Atwood Duniet z Soni method
0
0
| ( ) |0.060 0.003
| ( ) |D
A D K
A Dr
KInput:
Count B candidates with opposite sign kaons Count B candidates with opposite sign kaons
2 2([ ] ) ([ ] )2 cos( )cos
([ ] ) ([ ] )ADS D B B D D B
Br K K Br K KR r r r r
Br K K Br K K
([ ] ) ([ ] )2 sin( )sin /
([ ] ) ([ ] )ADS B D D B ADS
Br K K Br K KA r r R
Br K K Br K K
D decay into flavor stateD decay into flavor state
Phys.Rev.Lett.91:171801,2003
B D
D decay strong phase D unknown
Gianluca Cavoto9
ADS results
D0K D*0(D0 0)K D*0(D0 )K
1.30.8
2.
4.0.
1.4
2
1
3
*( )
*( )
([
([ ] )
] ) 0.2
([
.
)
7
] 1.2
4D
D D
D D
N K K
N
N
K
K
K
KNBB=227 106
No signal in current datasetNo signal in current dataset
Gianluca Cavoto10
rB f rom ADS method
RADS R*ADS
0.030 (90%CL)ADSR * 0.021 (90%CL)ADSR
0.23 (90% )Br CL * 0.21 (90% )Br CL
No AADS measurement
1
48 73
D
D
o o
any
r
any
D0K D*0(D0 0)K D*0(D0 )K
Sensitive to rB (RADS~r2B)
Not easy to determine Not easy to determine
Gianluca Cavoto11
B- D(*)0 - D0( S ) Dalit z analysis
=75, =180,rB=0.125
Isobar model for f(m2+ ,m2
- )can fix phase variation
D across Dalitz plot.
Only two-fold ambiguity in extraction
Sensitivity to
Amplitude for B-/B+ D0 K-/K+Amplitude for B-/B+ D0 K-/K+
202 )( SKMm202 )( SKMm
If we knew the charm phase shift D?If we knew the charm phase shift D?
DCS K*(892)
(770)
Gianluca Cavoto12
D0( S ) Dalit z model
Plot of mpipi
Determined on D* D0 sampleDetermined on D* D0 sample
No D-mixing, No CP violation in D decays
(770)
CA K*(892)
DCSK*(892)
2m
2m 2m
Gianluca Cavoto13
B- D0 - , B- D*0 -
261 19
83 11
40 8Dalitz projection for mES >5.272 GeV/c2
Signal plus backgroundPDF superimposed
NBB=211 106
B+ B+
B- B-
0B D K
DCS K*(892)
DCS K*(892)
D0K
D*0(D0 0)K
D*0(D0 )K
2m
2m 2m
2m
Gianluca Cavoto14
f rom B- D(*)0[ S ]
With current statistics, no rB sensitivity for rB<0.10 With current statistics, no rB sensitivity for rB<0.10
0.18 (90% )Br CL * 0.24 (90% )Br CL
Bayesianconfidence regions
Bayesianconfidence regions
D0K-
68%
95%D*0K-
D0K- D*0K-
* (311 52 23 10)oB
(88 41 19 10)o
Dalitz model syst
180
-180
0
180
0
0.3
0.3
r*B
(130 45 8 10)oB
rB-180
0.3 0.30. 0.
A posteriori rB(rB*) with uniform a priori
Gianluca Cavoto15
Crit ical rB
rB
D0 Dalitz
measurement fromcombination of many modes(multiple constraints on rB)
measurement fromcombination of many modes(multiple constraints on rB)
rB =0.1
rB =0.2
rB =0.3
, 13062 , 15o oB D
o
0 90 180
GLW only ADS only ( D and Bunknown)GLW+ADS
sensitivity projection for 500 fb-1
2
0.23 (90% )Br CLFrom ADS
21
1ADS B
D
B
A SB
R r
A Ar
R rGLW ADS
= 62o
Gianluca Cavoto16
sin(2 + ) with B0 D(* )- +/ +
Time dependent CP analysisTime dependent CP analysis
favored b c amplitude suppressed b u amplitude
|||| *1 udcbVVA
time-dependent CP violation arises from interference of mixing and decay:
0B0
B
(*)D
iicdub eeVVA |||| *
2
2
b u
dc
dd0
B
*DubV
*cdVu
d
dd0B *D
*cbV
udV
b c
The final state is accessible from both B0 and B0
Exclusive reconstruction of D- +, D*- +,D- +
Partial reconstruction of D*- +
D*Combinatoric BBPeaking BBContinuum
Lepton tag
*0 DB
softD0
X
Asymmetry
parameters
2 sin(2 )cos
2 cos(2 )sinlep
a r
c r
~ ~
Gianluca Cavoto17
B0 D(*)0 (*)0
(*)0 00
00 (*)0
( )
( )
B D Kr
B D K
Sensitivity given by
0 *00 ( )B D K K
Search for b u transition(self tagging mode)
Eventually TD analysis
No signal
NBB=124 106
0 0 *0 5( ) 4.110 90% . .BR B D K at C L
Gianluca Cavoto18
Unit arit y t riangle const raints
Confidence regions in planeConfidence regions in plane
Combination of BaBar a and c results with uniformprior in r
Search for B0 DsImprove bound using SU(3) r from B0 D+
s-
3( ) 9.5 10 90% . .r D at C L
Not encouraging for D
http://www.utfit.orghttp://www.utfit.org
NBB=90 106
.
68% C.L. 95% C.L.
(*)
(*)
0 (*)(*)
0 (*)
( )tan
( )S
S DC
D
fBR B Dr
BR B D f
Phys.Rev.Lett.90:181803,2003
* 0.0050.007
0.019 0.004
0.017
r
r
hep-ph/0408079
Gianluca Cavoto19
More modes and techniques added to measureGLW, ADS, D0K Dalitz, time-dep. sin(2 + )
No single golden technique
Constraints on b u amplitude in B DKEvidence for small rB
Sensitivity to relies heavily on rB
from combination of many modes
Combination of BaBar GLW+ADS+D0K Dalitz
Conclusion
68 %C.L.
( )
( )B
A b ur
A b c
95 % C.L.
Gianluca Cavoto20
Backup slides
Gianluca Cavoto21
sin(2 + ): results
Exclusive reconstruction of D- +, D*- +,D- +
Higher resonance Included in syst.error
- higher signal purity, lower efficiency
Partial reconstruction of D*- +
- high efficiency, more background
NBB=110 106
NBB=178 106
*
:
: , ,
1 ( )
i flavor tag category
D D D
flavor
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