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Interference Effects in D Meson Decays

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Title: Interference Effects in D Meson Decays


1
Interference Effects in D Meson Decays
  • D. Cinabro
  • Wayne State University
  • FPCP 2006, 12 April

2
Why Interference Effects?
  • Provide unique information
  • Phases and amplitudes are otherwise inaccessible
  • Need these to extract fundamental parameters (CKM
    elements for example) from other measurements
  • Challenge and input for QCD

3
Outline
  • New results (since summer 2005) are thin
  • D?KK?0 Dalitz analysis for D?KK strong phase
    from CLEO-III
  • D?3? Dalitz analysis from CLEO-c
  • Quantum Correlations in D0D0 decays from the ?
    for phases and mixing parameters from CLEO-c

_
4
CLEO Data Sets
  • CLEO-III data on ?(4S), 9/fb with charm produced
    in continuum or from B decay
  • CLEO-c data on the ?, 281/pb, which
    corresponds to 1.4M D pairs.

5
CLEOc Detector
  • Venerable CsI Calorimeter 2.2 resolution on 1
    GeV photon, 5 on 100 MeV, ?p/p 0.6 at 1 GeV,
    RICH particle ID

6
CLEO-III D?KK?0
  • Motivation is to extract strong phase difference
    in D?KK
  • See Grossman, Ligeti, and Soffer (PRD
    67(2003)07130) and Rosner and Suprun
    (PRD68(2003)054010) for how this helps measure
    CKM ? (?3) in charged B decay

7
D?KK?0 Charged D Tag
  • 600 Signal SB41, Soft ? tag gives D0 flavor

8
D?KK?0
  • Both charges of K and ? contributions clearly
    visible
  • Interference between Ks is also clear

9
D?KK?0
10
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11
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12
CLEO-III D?KK?0
  • Preliminary
  • ?D?KK 332o8o11o, large interference
  • A(D?K-K)/ A(D?KK-) 0.520.050.04
  • Precision limited by non-K contributions to the
    decays
  • Observed branching fractions consistent with
    previous measurements

13
CLEO-c D?3? Dalitz
First time doing a Dalitz analysis that has been
done by E791 and FOCUS (previously concentrated
on modes with ?0) 2600 signal on SB of 21
(E791 1200, FOCUS 1500) Mbc ?Ebeam2 p3?2, ?E
Ebeam - E3?
__________
14
D?3? Dalitz
  • Symmetry under interchange of like-sign pions
  • Dalitz analysis on high mass versus low mass
    unlike-sign pion combinations
  • Big vertical stripe is Ks?

15
D?3? Dalitz
  • Worry that efficiency will be difficult in
    corners of the Dalitz plot since D starts nearly
    at rest.
  • Looks good, changes are smooth.
  • Model with both MC bin-by-bin and polynomial fit.

16
D?3? Dalitz
  • Backgrounds from sidebands (offset in ?E to
    insure that it remains on the Dalitz plot)
  • Add in Ks, ?, f0(1370) to represent possible
    resonance contributions

17
D?3? Dalitz Many potential contributions
18
D?3? Dalitz
f2?
??
??
f0?
19
D?3? Dalitz
FF in E791 CLEOc
?? 33.63.9 20.02.5
?? 46.39.2 41.82.9
f2? 19.42.5 18.22.7
f0(980)? 6.21.4 4.10.9
f0(1500)? ---------- 3.41.3
Non-res 7.86.6 lt3.5
?(1450)? 0.70.8 lt2.4
Prob(?2) 96.3 27.8
20
CLEO-c D?3? Dalitz
  • Still preliminary
  • Need to consider other models of ?? S-wave (for
    example replace ? and f0 contributions by
    generalized ?? interaction) to compare with FOCUS
    which used the K-matrix
  • Broad agreement with E791 (? contribution, first
    observation for CLEO)

21
CLEO-c TQCA
  • K-? vs semileptonic measures isolated decay rate
    and tags flavor of decaying D
  • Different sensitivity to mixing vs DCSD
  • D decays to CP eigenstates also interfere and
    opposite semileptonics to get isolated rate,
    flavor tags for yet another dependence on y and
    strong phase
  • CP eigenstate vs CP eigenstate shows maximal
    correlations
  • The Quantum Correlation Analysis
  • ee???D0D0 is C -1
  • K-? vs K?- interfere and thus sensitive to DCSD
    and strong phase
  • Time integrated rate depends on both cos?D?K? and
    mixing parameter y ??/2?
  • K-? vs K-? forbidden unless there is mixing.

-
22
TQCA
See PRD 73 034024 (2006) hep-ph/0507238 by
Asner and Sun
RM (x2y2)/2 r Amp DCS/Amp CF
f l CP CP-
f RM/r2
f 1r2(2-(2cos?)2)
l- 1 1
CP 1r (2cos?) 1 0
CP- 1-r (2cos?) 1 2 0
X 1 ry (2cos?) 1 1-y 1y
-
And measure branching fractions simultaneously
23
TQCA Single Tags in Data
K-?
K?-
KK
Ks?0
Ks?0?0
??
24
TQCA Double Tags in Simulation
M(K-?)
M(K-?)
M(K?-)
M(K-?)
M(KK)
M(KK)
M(K-?)
M(KK)
25
TQCASemileptonics
Opposite K? Flavor Tag
Opposite CP- Tag
Signal
Backgrounds
Electron Momentum (GeV)
Electron Momentum (GeV)
26
TQCA
CP tags vs CP tags clearly shows Quantum
Correlation
No QC Data K-K ?-? Ks?0?0 Ks?0
K-K 5.20.4 -2.21.9 4.50.3 0.10.9 5.70.4 1.61.3 16.00.6 39.66.3
?-? 1.10.2 0.21.4 2.20.2 1.61.3 5.80.4 14.03.7
Ks?0?0 1.20.2 1.01.0 7.30.4 19.04.4
Ks?0 9.70.5 3.01.7
CP
CP-
C P
CP-
27
TQCA
K-? vs K-?
K-? vs K?-
Data clearly favors QC interpretation
showing constructive and destructive
interference and no effect as predicted
CP vs CP
CP- vs CP-
CP vs CP-
K? vs CP
K? vs CP-
28
Parameter CLEO TQCA PDG or CLEOc
y -0.0570.066? 0.0080.005
r2 -0.0280.069? (3.740.18)X10-3
r (2cos?D?K? ) 0.1300.082?
RM (1.741.47?)x10-3 lt 1x10-3
B(D?K?) (3.800.029?) (3.910.12)
B(D?KK) (0.3570.029?) (0.3890.012)
B(D???) (0.1250.011?) (0.1380.005)
B(D?Ks?0?0) (0.9320.087?) (0.890.41)
B(D?Ks?0) (1.270.09?) (1.550.12)
B(D0?Xe?) (6.210.42?) (6.460.21)
29
CLEO-c TQCA
  • Obviously still preliminary, but very promising
  • Systematics look tractable (lt stats)
  • Number of CP tags is limit so working on adding
    more
  • C fraction lt 0.060.05? on ?
  • Ultimate sensitivity with projected CLEO-c data
    set y 0.012, x2 0.0006, cos?D?K? 0.13,
    x(sin?D?K?) 0.024 (needs C1 initial state from
    running above the ?)

30
Conclusions
  • Unique information from interference effects in D
    decays
  • All since summer 2005 from CLEO
  • ?D?KK 332o8o11o and A(D?K-K)/
    A(D?KK-) 0.520.050.04 in D?KK?0 Dalitz
  • D?3? Dalitz agrees with E791 on need for low
    mass ?? S-Wave contribution
  • CLEO TQCA sensitive to D mixing parameters and
    ?D?K?
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