Marina Artuso 1 Beyond the Standard Model: the clue from charm Marina Artuso, Syracuse University D o D o , D o K - + K - K + + K - K +
Marina Artuso 1
Beyond the Standard Model:
the clue from charmMarina Artuso,
Syracuse UniversityDoDo, DoK-+
K-
K+
+
K-
K+
Marina Artuso 2
Experimental strategies considered
Mixing Comparison between hadronic and lepton tagged modes
from C=1 DoDo pairs Study of “right-sign” leptons versus “wrong sign
leptons” CP violation
Direct CP violation in Do and D+
Indirect CP violation in Do decays CP violation measurements exploiting the quantum
coherence of the DoDo pair Rare and forbidden decays Decay constants revisited
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A glimpse into the world of new physics?
Mixing CP violation } Exploit quantum
coherence of initial state at the and D0D0
Study interference effects induced by strong phases (Dalitz plot analyses)
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D0D0K+K+& rD
•No rDCSD component because of quantum statistics
•Sensitivity can be enhanced by adding other modes (such as K(*)
+l(*)l).
•Standard Model predictions quite uncertain. We will not span the full range of Standard Model predictions, but we may see “new physics driven”, possibly distinguishing x from y
2
22 yxrD
UL(sqrt(rD))0.01 @95%CL
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A COMPREHENSIVE MAPPING
OF MIXING PARAMETERS - 1
Final state (C=-1) (C=+1)K-+K-+ A4(x2+y2)/2 4A4(r2+ry’+3/8(x2+y2)
K-+K+- A4(1-2r2cos2-1/2(x2-y2))
A4(1+2r2cos2-+4ry-3/2(x2-y2))
K-+S A2AScos A2AS
y
Comparison of CPeven and odd allows determination of cos
Linear in y
hep-ph/0103110Gronau, Grossman & Rosner
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CP eigenstates
CP(+1) eigenstates
Channel B.F.(x103) 3fb-1 #(3fb-1 D0D0)
K-K+ 4.1 110,000 9,400
1.6 36,000 3,000
15.0 54,200 4,600
CP(-1) eigenstates
s 3.5 61,600 5,300
s 6.0 98,400 8,400
s 10.6 176,000 15,000
s 10.0 141,000 12,000
s 4.3 39,100 3,300
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Phase determination from C=-1 sample
2 cosS
SCS
SD D
S
A r
•We sum over all the CP eigenstates of a given sign to
obtain =(K-+S+)
•We can use MM technique to increase statistics
•Expected accuracy in cos is 0.05
S
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Lepton tagged samples
Final state (C=-1) (C=+1)
K-+l - A2A2(1-1/2(x2-y2)) A2 A2 (1+2ry-3/2(x2-y2))
K-+ l + A2 A2 (r2-1/2(x2+y2)) A2 A2 (1+2ry+3/2(x2+y2))
Sl + A2 ASy2 A2 A S
y+3y2)
l-
l+
l-
l+
~
l+
l+
CP even – CP odd asymmetries linear in y
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CP Violation experimental search
techniques Direct CP violation in D decays CP violation in the decay of a Do Do pair CP violation in final state distributions
(DVV) Order of magnitude expected in Standard
Model 10-3
New physics can enhance CP asymmetries + in this scenario they can emerge in Cabibbo allowed modes
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CP violation in charm decays
Present experimental data: FOCUS Acp(D+K-K++)=-0.0010.0220.015, FOCUS result Acp(K+K-)=-0.0010.022 0.015
CLEO Acp(D0K-K+)=+0.050.02180.0084
CLEO-C error 0.01 with 3 fb-1 with a variety of techniques. In some measurements b-factories are very competitive
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CP asymmetries from flavor tagged decays
)]KK)(ek[(N)]KK)(ek[(N
)]KK)(ek[(N)]KK)(ek[(Na cp
•Necessary ingredients:
•Flavor tag (lepton/kaon)
•CP eigenstate
•Obtain acp, for example:
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Acp with flavor tagged CP eigenstates
CP eigenstate
Flavor tagged sample
A
K+K- 10,200 0.01
Ks0 10,400 0.01
Ks 3,500 0.02
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Acp sensitivities
Self tagging modes (D+, Ds)
O(10-3)0.009D++K*0
O(10-3)0.007D++O(10-3)0.008D++
SM predictions
Acp(Lint=3 fb-1)Mode
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DoDo f+ f+ or f- f-(f+=K+K-,+-,Ks
•A single background free event CP violation
CP eigenstate 1 CP eigenstate 2 # for 100% CPV
K+K- K+K- 174
K+K- Ks0 171
K+K- 00 183
Ks0 Ks0 136
•We can increase statistics x3-4 using MM technique discussed before
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CP violation studies in the Dalitz Plot
High statistics background free DalitzPlot analyses may turn out to be the most sensitive probes of CP violation in D decays
Not only “Beyond SM”, also QCD etc..
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Rare and forbidden decays
Some D decays are forbidden: Standard Model expectations are several order of magnitude below any experimental reach laboratory for “Standard Model background free” searches for new physics
the charm threshold region has the advantage of high efficiency and low background both for charged particle final states and final states including and o.
Sensitivities to branching fractions (10-6) expected
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Leptonic Decays: D l
+ Introduction: Pseudoscalar decay constants
Q and q can annihilate
probability is to wave function overlap
Example -:
22+ 2 2 2
221
(P ) 1 | |8 F P P Q
Pq
mG m M Vf
M
In general for all pseudoscalars:
_
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fD and new physics
22
2
22
2
( )
( )1
1s
s
s
s
D
DB D
D
m
m
mm
mm
B
We can probe violation of universality
222
2ta( ) 1 1 nsD s
s l SM
H cm
m mB D l B
m
Effect can be a few % with new physics
2HDM prediction
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Summary on decay constant reach
Decay mode
Decay constant
½
B/B½
Vcq/Vcq
fDq/fDq
D+ fD 1.9% 0.6% 1.1% 2.3%
Ds fDs1.4% 1.0% 0.1% 1.7%
Ds fDs1.2% 1.0% 0.1% 1.6%
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Conclusions
CLEO-c can probe for physics beyond the Standard model with 4 different strategies Mixing studies CP violation studies Rare decays Precision decay constant measurements
Phenomenology is very rich, some measurements unique (quantum coherence of initial state)
Search for signatures of physics beyond the Standard Model in charm is very important and our studies will be complemented by other experiments (BaBar, BELLE, BTeV…)