expectation experiments rate asymmetries other approaches outlook
DESCRIPTION
CP Violation in D Meson Decays Mats Selen, University of Illinois 2002 FPCP Meeting, University of Pennsylvania. Expectation Experiments Rate Asymmetries Other Approaches Outlook. Indirect CPV:. G ( ) ≠ G( ). - PowerPoint PPT PresentationTRANSCRIPT
M. Selen, FPCP/02 1
• Expectation
• Experiments
• Rate Asymmetries
• Other Approaches
• Outlook
CP Violation in CP Violation in D Meson DecaysD Meson Decays
Mats Selen, University of Illinois
2002 FPCP Meeting, University of Pennsylvania
M. Selen, FPCP/02 2
0D
0D
f( ) ≠ 0D
0D
f
Indirect CPV:
Very small in charm since mixing is suppressed(i.e. good hunting ground for new physics)
( ) ≠ Direct CPV:
D f
11
ieA
22
ieA
D f
1*1
ieA
2*2
ieA
3
21*21
2
2
2
1
21*21 10
)(2
)(2
)()(
)()(
cosAReAAA
sinAImA
ff
ffACP
M. Selen, FPCP/02 3
Since this decay isSingly Cabibbo Suppressed…
Direct CPV:
1) Consider D0 →
(same for K+KK+KK+K, , ,etc)
0Dc
u
u
d
u
d
W+
M. Selen, FPCP/02 4
0Dc
u
u
d
u
d
d,s,b
W+
Direct CPV:
…we can modify it’stopology in a simpleway to get a penguin:
1) Consider D0 →
(same for K+KK+KK+K, , ,etc)
M. Selen, FPCP/02 5
0Dc
u
u
d
u
d
W+
0Dc
u
u
d
u
d
b
W+
udcdVV *
ubcbVV *
differentweak
phases
differentstrongphases
are likely
2
3,
2
1I
2
1I
We have theingredients:
Expect ACP < 10-3
in most cases
M. Selen, FPCP/02 6
2) Consider D+ → KS
(also KS, KSa1, K*[KS KS DSKSK[KS]K*Ketc)
Dc
ds
u
d
SKK 0
W+
d
Dc
d
SKK 0
W+
s
d
u
d
CabibboFavoredDecay
DoublyCabibboSuppressedDecay
M. Selen, FPCP/02 7
D
SKK 0
CFDSKK 0DCSD
D
dCdKSS
SSCP sinsintanR
)KD()KD(
)KD()KD(A
22
Lipkin& Xing
M. Selen, FPCP/02 8
≤ 10-3
in SM(from data)
hopefully big(measurablein principle)
~5x10-2~1From CPV in
K0 system~ 3x10-3
D
SKK 0
CFDSKK 0DCSD
D
dCdKSS
SSCP sinsintanR
)KD()KD(
)KD()KD(A
22
New physics couldmake this much bigger
Lipkin& Xing
M. Selen, FPCP/02 9
)KD()KD(
)KD()KD(A
SS
SSCP
Bigi & Yamamoto, Phys. Lett B349 (1995)See Lipkin & Xing, Phys. Lett B450 (1999)
3x10-3 + new physics
So what?
• D+ → KS+, KS+, KSa1+…
• D0 → KS0, KS …
• Should be able to see K induced CPV with 107-108 reconstructed D events.
- This is in the ballpark for CLEO-c/Belle/BaBar
• New physics could make this asymmetry much bigger by increasing weak (and strong) phase differences.
- If seen, this can be studied using a suite of decays involving KL and KS in final state.
not suppressed (big BR)
M. Selen, FPCP/02 10
The usual suspectsThe usual suspects
M. Selen, FPCP/02 11
CommentsComments Since D+ and D (and similarly D0 and D0) are not produced in equal numbers in FOCUS and E791,
these experiments normalize all asymmetries to some known Cabibbo favored mode.
e+e experiments need to worry about, A+, AFB
DD
DDKKACP
KDN
KKDND
For example:
where
M. Selen, FPCP/02 12
These modes are “self-tagging” (no D* needed).
E791 D+ → K+K+, + ,K*(892)0+, ++
FOCUS D+ → K+K+, KSK+, KS+
DD++ Decays Decays
M. Selen, FPCP/02 13
73710 ± 29268607 ± 282
D+→ D→
7355 ± 112
D→
6860 ± 110
D+→
M. Selen, FPCP/02 14
5080 ±110
D+→S
5518 ±110
D→S
495 ±38
D+→S
454 ±42
D→S
M. Selen, FPCP/02 15
1031± 44
1265± 48
474± 25
598± 28
D+→
23465± 183
28014± 201
D→
D+→ D→ D+→ D→
M. Selen, FPCP/02 16
239± 18
291± 19
697± 42
851± 48
D+→ D→D+→ D→
M. Selen, FPCP/02 17
-10-505
1015
K-K
+P
i+
KsP
i+
KsK
+(K
pp
)
KsK
+(K
sP)
K-K
+P
i+
Ph
iPi+
K*
K+
PiP
iPi
AC
P (
%)
stat
stat & systD± ACP
Summary
FOCUS E791
S S+
()
± 1.1 ± 0.5
S ± 1.5 ± 0.9
S ± 6.0 ± 1.5
SS ± 6.1 ± 1.2
± 2.9
± 3.6
± 5.0
± 4.2
S+
(S)
* All analyses statistics limited.* None are background free.
M. Selen, FPCP/02 18
DD00 Decays Decays
Use D* decays to tag D0 flavor:
E791 D0 → K+K, +, K++
FOCUS D0 → K+K, +
CLEO D0 → K+K, +, KS0, KSKS, 00
0* DD
fD 0
0D0D
M. Selen, FPCP/02 19
KKD 0
333±21
KKD0
276±20
0D149±17
0D194±18
KD 0
7198±95
KD0
6075±87
M. Selen, FPCP/02 20
KKD 0
1707±53
KKD0
1623±47
0D
606±31
0D
571±33
KD 0
19633±149
KD0
18501±144
M. Selen, FPCP/02 21
KK
DD 00
2463±65
930±37
9099±151
0000 sKDD
00 DD
)(histogram
(points) 0
0
D
D
M. Selen, FPCP/02 22
810±8965±14
0000SS KKDD 0000 DD
)(histogram
(points) 0
0
D
D)(histogram
(points) 0
0
D
D
M. Selen, FPCP/02 23
-15-10
-505
1015
K+
K-
Pi+
Pi-
KsP
i0
Pi0
Pi0
KsK
s
K+
K-
Pi+
Pi-
K+
K-
Pi+
Pi-
AC
P (
%)
stat
stat & systD0 ACP
Summary
CLEO FOCUS E791
S SS
± 2.2 ± 0.8
± 3.2 ± 0.8
S ± 1.3
± 4.8
S S ± 19
± 2.2 ± 1.5
± 3.9 ± 2.5
± 4.9 ± 1.2
± 7.8 ± 2.5
* All analyses statistics limited.* None are background free.
M. Selen, FPCP/02 24
Other Promising ApproachesOther Promising Approaches
Look for CPV in Dalitz Plots: Analyze D and D samples separately Any differences in amplitudes & phases is an indication of
CPV. Work under way by several groups.
Examples from CLEO D0 → K+(Published last year). D0 → KS +(Preliminary results). D0 → +(soon…) D0 → S0(soon…).
M. Selen, FPCP/02 25
D0
K
D0
K
Y
K
D0
X
D0 K
Z
D0→
M. Selen, FPCP/02 26
Resonance Fit Fraction Phase
(770) 0.788 0.023 0 (fixed)
K(892) 0.161 0.010 163 4
K(892) 0.127 0.010 0 4
(1700) 0.057 0.011 171 7
K (1430) 0.041 0.009 166 7
K (1430) 0.033 0.009 56 7
K(1680) 0.013 0.004 103 11
Non-res 0.075 0.011 31 7
We are sensitive to the amplitude and phase of something with BR ~ 10-3.
(Show Movie)
M. Selen, FPCP/02 27
Fit D0 and D0 Dalitz Plots separately and look for asymmetries:
Find ACP = 0.031 0.086
DPd
DD
DD
22
22
00
00
MM
MMACP
(Not an optimized ACP analysis)
M. Selen, FPCP/02 28
Almost nobackground
D0→S
Fit D0 and D0 samples separately
0400300200202
1 ..ie..p
210
210
2
1
2
1
DDq
D
DDp
D
122 qp
writing
with
PRELIMINARY:
M. Selen, FPCP/02 29
E791 and FOCUS Working on ACP analyses (for example Dalitz plots).
CLEO-c Still working on analyses using CLEO-II, II.V and III data. CLEO-c will turn on in about a year.
~30 million DD events (and new ACP search modes).
~ 1.5 million DsDs events
B Factories In the next 5 (?) years Belle and BaBar will accumulate
~100 times the integrated luminosity that CLEO has at the (4S). Improve on present CLEO limits by at least a factor of 10.
Hadron Machines CDF & D0 are getting into the game. BTeV (& LHC-b ?) could have 109 reconstructed charm events. COMPASS ? Others ?
BES
Outlook (is interesting)Outlook (is interesting)
E791
CLEO
M. Selen, FPCP/02 30
Extra Slides…Extra Slides…
M. Selen, FPCP/02 31
Observing this is evidence of CP
At the ”(3770)
e+ e
0D
0D
+
K+
e+e ” D0D0
JPC = 1
i.e. CP+
Suppose both D0’s decay to CP eigestates f1 and f2: These can NOT have the same CP :
CP(f1 f2) = CP(f1) CP(f2) (-1)l = CP
+ (since l = 1)
CPV through quantum CPV through quantum coherence at CLEO-ccoherence at CLEO-c
Sensitivity to this will be at the ~1% level
M. Selen, FPCP/02 32
DD00→→AACPCP Fits Fits