Transcript CLEO-C: prospects and relevance to LHCb

Hadronic Charm Decays & Do-Do Mixing
Sheldon Stone,
Syracuse University
FLAVOR Physics & CP Violation, April 9-12, 2005
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What We Hope to Learn

Charm Mixing & CP Violation


Can we see new physics? SM mixing & CP
violation is small, so new effects don’t have
large SM background as in the K or B systems
Hadronic Charm Decays

Engineering numbers useful for other studies


BCharm is dominant, so knowing lots about charm
is useful, e.g. absolute B’s, resonant substructure,
phases on Dalitz plots, etc…
Learn about Strong Interactions, esp. final state
interactions
FLAVOR Physics & CP Violation, April 9-12, 2005
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Absolute Charm Meson
Branching Ratios & Other
Hadronic Decays
o
D,
3
+
D
& DS
Experimental methods
DD production at threshold: used
by Mark III, and more recently by
CLEO-c and BES-II.
Unique event properties
Only DD not DDx produced
Large cross sections:
World
Ave
s(DoDo) = 3.720.09 nb
s(D+D-) = 2.820.09 nb
s(DSDS*) = ~1.1 nb
Continuum ~14.5 nb
 Ease of B measurements
using "double tags“
p
 BA = # of A/# of D's
B-factories (e+e-) + fixed target & collider
(ps)
experiments at hadron machines
e+
D displaced vertex
D*+ p+D0 tag, or DS* gDS
FLAVOR Physics & CP Violation, April 9-12, 2005
K
D0
e-
4
+
D K p+p+ at
the y´´ (CLEO-c)
Single tags
D+K-p+p+ or
D-K+p-p-,
80,865 events
Double tags
D+K-p+p+ &
D-K+p-p2002 events
M2D = Ei2 - Pi2 =E 2beam - Pi2
281 pb-1 of data at y(3770)
FLAVOR Physics & CP Violation, April 9-12, 2005
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Absolute B Results for D+ & Do 57 pb-1
B(DoK-p+)
B(D+K-p+p+)
CLEO-c
(not in average)
B (%)
Error(%)
Source
B (%)
Error(%)
Source
9.52 0.250.27
3.9
CLEO-c
3.910.08 0.09
3.1
CLEO-c
9.2±0.6
6.5
PDG
3.81±0.09
2.4
PDG
9.43 0.31
3.3
World avg
3.85 0.07
1.9
World avg
FLAVOR Physics & CP Violation, April 9-12, 2005
For 281pb-1, ~few weeks:
2.2% projected error 1.8% projected error6
CLEO DS+ Results at 4170 MeV


Since e+e-DS*DS, the DS
from the DS* will be smeared
in beam-constrained mass.
cut on MBC & plot invariant
mass (equivalent to a p cut)
KsK+
Signal MC
MBC
from DS*
MBC
hp+
69735
27121
Inv Mass (GeV)
FLAVOR Physics & CP Violation, April 9-12, 2005
Inv Mass (GeV)
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Ds+ → K-K+p+ from CLEO-c (72 pb-1)
Ds+ → K-K+p+
305778
Ds+ → K* K+
126247
(GeV)
FLAVOR Physics &Inv
CPMass
Violation,
April 9-12, 2005
Ds+ → f p+
119736
±20 MeV
cut around
f mass
Ds+ → f0(980) p+
11112
Inv Mass (GeV)
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Ds+ → K-K+p+ from
Fit results
Fit frac.
K*0 (892)
0.44 ± 0.01
K*0 (1430) 0.06 ± 0.01
f (1020)0.45± 0.01
f0 (980)
0.16 ± 0.01
fj (1710)
0.04 ± 0.01
Phase (Deg)
0.0 (fixed)
114 ±5
148 ± 4
135 ± 4
106 ± 8
E687 published result
Fit frac.
From Sandra Malvezzi CIPANP 2000
AIP Conference Proceedings -- December
12, 2000 -- Volume 549, Issue 1, p. 569
FLAVOR Physics & CP Violation, April 9-12, 2005
K*0 (892)
0.48 ± 0.05
K*0 (1430) 0.09 ± 0.03
f (1020)0.40± 0.03
f0 (980)
0.11 ± 0.04
fj (1710)
0.03 ± 0.02
Phase (Deg)
0.0 (fixed)
152 ± 40
178 ± 20
159 ± 22
110 ± 20
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Single & Double DS+ Tags in 76 pb-1

Modes:
Different
selection criteria
than other analyses
 Clean double
tag signal
Invariant mass2 (GeV)

Invariant mass1 (GeV)
FLAVOR Physics & CP Violation, April 9-12, 2005
Dm=mass1-mass2
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Absolute B Results for DS+ 76 pb-1
Mode
KSK+
B (%) (CLEO-c)
B (%) PDG
1.280.13
0.12  0.07
1.80±0.55
K+K-p+
4.540.44
0.42  0.25
4.3±1.2
K+K-p+po
4.830.49
0.46  0.46
1.020.11
0.10  0.05
1.00±0.28
p+p+p


About ±11% error
Results are preliminary: more modes are
being added & more data is being taken
What about DSfp+ ?
FLAVOR Physics & CP Violation, April 9-12, 2005
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The Effective B(DSfp+)



CLEO does not quote it. Because of the presence
of f0p & other interferences on the Dalitz plot, the B
you get depends on your mass resolution & your
mass cut
I, however, will make an estimate based on CLEO’s
mass resolution since many experiments have similar
resolution. (Note that the observed f line shape is a
convoluted BW & Gaussian)
Using a ±10 MeV K+K- mass cut about the f mass
(91% efficient on the f), I find from the observed ratio
of fp/KKp events: Beff(DSfp+)=(3.49±0.39)%. For
±20 MeV cut (97% efficient) (3.73±0.42)%, which
gives a scale of the mass cut sensitivity
FLAVOR Physics & CP Violation, April 9-12, 2005
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Previous Measurements of Beff(DSfp+)

Compare fully and partially reconstructed
BD*DS* decays
CLEO Beff(DSfp+)=(3.6±0.8±0.5)%
 BaBar Beff(DSfp+)=(4.8±0.5±0.4)%
5.11.8
eff
+
(3.9
 BES
B (DSfp )=
1.91.1 )%


Compare with my estimate
Beff(DSfp+)=(3.5±0.4)%.

Upper limit based on counting all known
modes <4.8% @ 90% c.l 5.2% based on
current data (Muheim & Stone Phys. Rev. D 49, 3767
(1994)). They also predicted B(DSfp+)=(3.6±0.6)%
FLAVOR Physics & CP Violation, April 9-12, 2005
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Inclusive ss Mesons from D decays
η (%)
η (%)
f(%)
Do
9.4 ± 0.4 ± 0.6
2.6 ± 0.2 ± 0.2
1.0 ± 0.1 ± 0.1
D+
5.7 ± 0.5 ± 0.5
1.0 ± 0.2 ± 0.1
1.1 ± 0.1 ± 0.2
DS


32.0 ± 5.6 ± 4.7 11.9 ± 3.3 ± 1.2
15.1 ± 2.1 ±1.5
Done using double tag events
f & h rates are much higher for DS, useful
for hadron collider b experiments
FLAVOR Physics & CP Violation, April 9-12, 2005
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Can be used to check Beff(DSfp+)




Procedure: take all modes containing f, h & h all
measured wrt to fp (bands are ±1s).If new modes are
found the slope of the bands would increase
CLEOc measurements are horizontal lines, also at ±1s)
Consistent with a 3.5% fp effective branching ratio
If more modes are found slope would increase, implying a
lower fpbranching ratio
FLAVOR Physics & CP Violation, April 9-12, 2005
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The Real B(DSfp+)




You can use a Dalitz plot fit (i.e. FOCUS) to get
the fraction of fp. This is not the same procedure
that was done in the past of merely cutting on the
K+K- invariant mass about the f.
The FOCUS Dalitz plot analysis has the fp+
fraction of K+K-p+ =0.45±0.01
Dividing the CLEO number for B(DS K+K-p+) by
B(fK+K-)=.491, gives B(DSfp+)=(4.16±0.41)%
This is the branching ratio that is most appropriate
to compare with theoretical calculations
FLAVOR Physics & CP Violation, April 9-12, 2005
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Cabibbo Suppressed Decays
CLEO-c
Mode
Branching Ratio x 10 -3
PDG
BaBar
D+Kp0 0.246±0.046±0.024±0.016
D+pp0
1.22±0.10±0.08±0.08
1.33±0.22
New value for phase
shift in Dpp modes
between DI=3/2 &
DI=1/2 amplitudes of
(86.4±2.8±3.3)o
CLEO-c
FLAVOR Physics & CP Violation, April 9-12, 2005
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Searches for New Physics in
Charm Decays
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 D0 (t ) 
  D0 (t ) 
i  0   ( M  i G 2)  0 
t  D (t ) 
 D (t ) 
Do-Do Mixing
Mixing could proceed via

{
Do


}
D
o
the presence of d-type quarks in
the loop makes the SM
expectations for Do- Do mixing
small compared with systems
involving u-type quarks in the box
diagram because these loops include
1 dominant super-heavy quark (t): Ko
(50%), Bo (20%) & Bs (50%)
New physics in loops implies
x DM/G>>y DG /2G;but long range
effects
complicate predictions
FLAVOR Physics & CP Violation, April 9-12, 2005
SM |x|
SM |y|
BSM |x|
From H. Nelson, updated by
A.A. Petrov hep-ph/0311371
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o
o
D - D mixing:

Wrong-sign
Complicated by interference between
DCSD & mixing [strong phase d will be
measured by CLEOc] x  x cos d  y sin d
(
Rws (t )  eGt RD  RD y ' Gt  14 ( x2  y2 )(Gt )2


Kp
Stolen from
Ligeti
)
Complicated by CP violation
Experiment
BaBar (2003)
x2 (x10-3) <@95 % CL
y(95% C.L.) (x10-3)
CPV
No CPV
CPV
No CPV
2.2
2.0
-56<y<39
-27<y<22
FOCUS (2004)
0.80
0.83
CLEO (2000)
0.82
0.78
-58<y<10
-52<y<2
Belle (2005)*
0.72
0.72
-28<y<21
-9.9<y<6.8
FLAVOR Physics & CP Violation, April 9-12, 2005
*consistent
-120<y<67 -72<y<41
with no mixing at 3.9% cl
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Other Studies



CDF WS/RS in Kp is
(4.05±0.21±0.12)x10-3 (350 pb-1)
Direct measurements of C=+
and C=- D0 lifetime differences
(yCP)
WS rate in semileptonic decays
measures (x2+y2)/2 directly
From PDG2004
FLAVOR Physics & CP Violation, April 9-12, 2005
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Dalitz Plot Analyses: D0 KSpp


CLEO: D0 KSpp full
time dependent analysis,
compared with BaBar
semileptonic analyses
Essential feature: distinct
time-dependence of DCP+, &
DCP- (CP+1, CP-1)
D1(t)~exp(-i(m1–iG1/2)t)
D2(t)~exp(-i(m2–iG2/2)t)
Limits are (-4.5<x<9.3)% & (-6.4<y<3.6) %, @ 95% C.L.,
without assumptions regarding CP-violating parameters.
FLAVOR Physics & CP Violation, April 9-12, 2005
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D0 K+ppo




BaBar: Uses Dalitz plot
to enhance Cabibbo
favored rate since it
proceeds largely via K-r+,
while wrong-sign rate
goes to K*+p- & K*opo
For CP conserving fit
Cabibbo favored
Wrong-sign
+0.18
R M = ( 0.23-0.14
±.04 ) x10-3
RM<0.54x10-3 @ 95% cl
RM is consistent with no
mixing at 4.5% cl
FLAVOR Physics & CP Violation, April 9-12, 2005
RD (%)
RM (%)
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CP/T Violation

Unexpectedly large CP violation asymmetries may be a
better signature for new physics (0.01-0.001)

CP violation can be studied in a variety of ways:

Direct CP violation

CP violation in mixing

T violation in 4-body decays of D0/D+ (assuming
CPT) and studying triple product correlations

Exploiting quantum coherence of DD produced in
y(3770) decays
FLAVOR Physics & CP Violation, April 9-12, 2005
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CP/T Violation: some recent data
Experiment Decay mode
BaBar
D+K-K+p+
BaBar
BaBar
D+ f+p+
D+ K*0 K
CLEO II.V
D0
CDF
CDF
FOCUS
FOCUS
FOCUS
D0 K+KD0 p+ pD0 K+K-p+ pD+ KoK+p+pDS KoK+p+
p+ p- p0
FLAVOR Physics & CP Violation, April 9-12, 2005
ACP (%)
Notes
1.41.0 0.8
0.21.50.6
0.91.70.7
+9
1-7 8
Res. Substr.
Of
D+K-K+p+
Dalitz plot
analysis
2.0 1.2  0.6 Direct CPV
1.0 1.3  0.6 Direct CPV
1.0 5.73.7
2.3 6.22.2
-3.6 6.72.3
T violation
through triple
product
correlations
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Conclusions on Absolute B’s

D meson absolute B scale now becoming well known:
 B(D+Kpp) =(9.430.31)% [CLEOc+PDG]
error 3.3% 2.1% (in a few weeks)
 B(Do Kp) =(3.850.07)% [CLEOc+PDG]
error 1.9% 1.4% (in a few weeks)
0.44
 B(DSK Kp) 4.540.42  0.25 [CLEOc]
error 11%  ~4-6% (this summer)
 Beff(DSfp+)=(3.49±0.30)% [SS]

Best to change base branching ratio for DS from
fp to something else. Suggest K+K-p, or KSK+
Already quite useful: # of charm particles/B decay:
1.09±0.04 (includes Do, D+, DS, Lc, Xc, 2x charmonium)

FLAVOR Physics & CP Violation, April 9-12, 2005
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Conclusions II


Many more Cabibbo suppressed & DCS
modes found. Large phase shifts in Dpp
No definitive evidence yet for charm mixing




Best limits are ~|y|<2.5% & |x2|<7.2% @ 95%
cl
Hints from Belle in wrong sign Kp decays
(only 3.9% cl for no mixing)
Hints from BaBar in wrong sign K+ppo decays
(only 4.5% cl for no mixing)
No observations of CP Violation
FLAVOR Physics & CP Violation, April 9-12, 2005
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The End
28
+
D K p+p+ at
the y´´ (CLEO-c)
Single tags
D+K-p+p+ or
D-K+p-p-,
15,120 events
Double Tags
D+K-p+p+ &
D-K+p-p377 events
M2D = Ei2 - Pi2 =E 2beam - Pi2
57 pb-1 of data at y(3770), CLEO now has 281 pb-1
FLAVOR Physics & CP Violation, April 9-12, 2005
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