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Tau-charm physics at B factories. Stephen L. Olsen, Univ of Hawai’i Chinas workshop-2006 June 11-18, Beijing. 馬 鵬. BaBar and Belle. e + (3.5 GeV/c). e - (8 GeV/c). Peak luminosity 1.08 10 34 cm –2 s –1 Integrated luminosity 363 fb –1. Peak luminosity 1.62 10 34 cm –2 s –1 - PowerPoint PPT Presentation
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Stephen L. Olsen, Univ of Hawai’iChinas workshop-2006 June 11-18, Beijing
Tau-charm physics at B
factories
馬 鵬
• Main purpose: Study CP violation in asymmetric e+e - (4S) BB
• Both experiments have far exceeded their design goals• Approx. 1 ab-1 integrated flux combined
BaBar and Belle
e- (8 GeV/c)
e+ (3.5 GeV/c)
Peak luminosity 1.081034 cm–
2s–1
Integrated luminosity 363 fb–
1
Peak luminosity 1.621034 cm–
2s–1
Integrated luminosity 602 fb–
1
B Factories are -charm factories
On
~5M charm particles/fb-1
ECM (GeV)
0.89 nb ~2M ’s/fb-1
-physics at B factories
• M
• Spectral functions– Non-strange & strange
• Rare decays
• Forbidden decays
m away from threshold
Lafferty Charm 2006
Precision measurements
79 fb-1
Strange spectral function
Belle
Path to world-best measurements of |Vus| and ms
Rare decaysHuge signals for decays
limits on decays
LFV decays,ℓ-ℓ-
ℓ+, etc
Lafferty Charm 2006
LFV limits from BaBar & BelleX10-7
Lafferty Charm 2006
constraints from limits
Lafferty Charm 2006
constraints from limits
Lafferty Charm 2006
Future for LFV decays
Charm physics
•Charmed particle spectroscopy
•Rare decays
•Form-factors
•DDbar mixing
Sources of charm at B-factories
D
c
d
u
q
D
D
• Continuum– D*-tagged– Recoil tags
• B decays
• Radiative return
c
c
Old new charmed-strange particles
BaBar BaBar
BDs DsJ decays are spin filters
BDsDsJ
J=0J=0 J=?; m=0
DsJ(2460)
DsJ(2317)J=0DsJ(2460)J=1
Belle
P –wave c-s mesons?
Broad D** states found by Belle
Masses coincide?
See tak by Dmitrasinovic @ Charm 2006
New new charmed-strange particles
DsJ(2860)D0K+
BaBar
Baryons, baryons, baryons..
Signal
c+ sideband
Feeddown from c(2880)+
cc++-- cc
++00 cc++++
ISOTRIPLET!
BelleBelle
Rare FCNC charm decaysRare FCNC charm decays
18Paul D. Jackson Charm 2006
FCNC decays only occur in loop diagrams in SM:
New physics can introduce new particles into loop Some models increase
BF(cull) to 10-6—10-5
No signal forFCNC charmdecays foundLimits on yieldsextracted withunbinned likelihood fits
Largest “signal”is ~1.5 in
c+pµ+µ– decays
D+e+e– D+µ+µ–
Ds+Ke+e– D
s+Kµ+µ–
c+pe+e–
c+pµ+µ–
Unblinded Mass DistributionsUnblinded Mass Distributions
Paul D. Jackson Charm 2006 24
Branching Fraction LimitsBranching Fraction Limits
26Paul D. Jackson Charm 2006
Improved limits in 17 modes, more than order magnitude in 12 modes
(preliminary)
Upper limits on BF (x10-6) at 90% CL
Ktag
D
mass-constrained vertex fits
e+ e-3.5 GeV 8 GeV
K
K
D0
slow
e/µ
D*-
„inverse“ fit
tag side
Recoil-tagged Charmed mesons
D*
signal side
additional primary mesonsIP
L. Widhalm Charm06
Form Factors – Comparison with Models
ISGW2 modellattice calculation modified pole model
D0 lD0 l
D0 lD0 l
pole mass (GeV)
Kl 1.82 ± 0.04stat ± 0.03syst
l 1.97 ± 0.08stat ± 0.04syst
simple pole
Kl 0.52 ± 0.08stat ± 0.06syst
l 0.10 ± 0.21stat ± 0.10syst
modified pole(poles fixed at theo. values)
fit results
f+(0)
Kl 0.695 ± 0.007stat ± 0.022syst
l 0.624 ± 0.020stat ± 0.030syst
Belle
L. Widhalm Charm2006
CLEO-c untagged with v-reconstruction
bcM
Decay Mode - Simple Pole |Vcd| f +(0) mpole
D0 ±e 0.146 ± 0.004 ± 0.003 1.87 ± 0.03 ± 0.01
D± 0e 0.152 ± 0.007 ± 0.004 1.97 ± 0.07 ± 0.02
Decay Mode - Modified Pole |Vcd| f +(0)
D0 ±e 0.142 ± 0.005 ± 0.003 0.37 ± 0.09 ± 0.03
D± 0e 0.151 ± 0.008 ± 0.004 0.12 ± 0.17 ± 0.05
Preliminary
f (q2 ) f (0)
1 q2 mpole2 f (q2 )
f (0)
1 q2 mpole2 1 q2 mpole
2 Simple Pole
ModelModified Pole
Model
D0→-e+ D0→-e+
2q
I Shipsey Charm2006
DDbar mixing using D*-tags
DDbar mixing limits
Covered by A Schwartz
Particles with hidden charm
Charmonium production in B decays
j=½
j=½
J = 0 or 1
Spectator model says Jcc= 0 or 1 shoulddominate exclusive BK(cc) decays.
charmonium states
All sub-open-charmthreshold states havebeen identified
Discovered at B factories
Allowed decays all have Bf~10-3
cK 0.9 x10-3
JK 1.0 x10-3
J/K* 1.4 x10-3
’K 0.7 x10-3
’K* 0.9 x10-3
c0K 0.6 x10-3
c1K 0.7 x10-3
J/K12701.8 x10-3
BK cc(J=2) still not seen
XYZ particles• X(3872)
– J/ in BKJ/
• Z(3930)– DD in DD
• Y(3940)– J/ in BK J/
• Z(3940)– DD* in e+e- J/ DD*
• Y(4260)– J/ in e+e- J/
Z(3931) DD at Belle
41 11 evts (5.5)
M=3931 4 2 MeV
208 3 MeV
sin4 (J=2)
Matches well to c2’ expectations
Z(3931) is most likely the c2’
3931
X(3940)
e+e-J/ + X
e+e-J/ + DD*
Seen in DD* but not DD; this implies c1’ or c”
but e+e-J/ +c0 not seen
Is the X(3940) the c”?
3940Mass is about
150 MeV too low
X(3872)
BK J/
M(J)
’J/
X(3872)J/
S.K. Choi et al PRL 91, 262001
C=+1 is establishedX(3872)J/ seen in:
Belle
&
M( looks like a (CDF)
X(3872)””J/ seen in Belle
angular analysis favors 1++ or 2 -+
X(3872) has no obvious cc assignment
3872
Masswidth way too smallAngular dist. wrong
c is allowed J/ is isospin forbidden
c”
2
MassJ/ way too smallc1’
Masswidth too smallAngular dist wrongc0’
Y(3940) in BK J/M≈3940 ± 11 MeV≈ 92 ± 24 MeV
S.K. Choi et al. (Belle)PRL94, 182002 (2005)
M(J/) MeV (Y3940 J/ > ~7 MeV (an SUF(3)-violating decay)
Is the Y(3940) the c1’ ?
Y(3940) J/ enhanced by FSI ?
Y
D
D*FSI
JIt seems strange (to me) that an SU(3)-violating
process can “short out” an SU(3)-allowed process
If the Z(3930) is the c2’ (which seems likely)the Y(3940) mass is too high for the c1’
Y(4260) /ISR Jee
J/ sideband
Well above DD & DD* threshold but wide & found in a suppressed
mode??
M=4259 8 MeV = 88 23 MeV
B. Aubert et al. (BaBar)hep-ph/0506081
Y(4260)
10.58 GeV
4.26 GeV
not seen in (e+e-hadrons)at Ecm =4.26 GeV
J.Z. Bai et al. (BESII)PRL 88 101802
BES
(e
+e
- h
ad
ron
s)
cc~5nb
CLEO-c results on the Y(4260)
58 12 pb
PRL 96 162003 (2006)
(Y4260)J/ > ~1.8 MeV>10x higher than what we are used to
DD** threshold in relation to the Y(4260)
4.26-mD
Is the Y(4260) a hybrid?Expect distortions of J/ line shape
DD1
No sign ofYDD** “turn-ons”
DD0*0 DD0’0
Summary• B factories are also -charm factories
• Sensitivity for rare and forbidden LFV decays probably better than at threshold region
• Many discoveries of new (& sometimes unusual) charmed and hidden-charm particles
謝 謝Thank you