Decays at CLEO

1
? Decays at CLEO
Steve BluskSyracuse Universityfor the CLEO
Collaboration

• Preview
• Introduction
• Measurements of B(?(nS) ? mm- )
• Electric Dipole Transitions
• ?(1S) ? ( c c ) X
• Summary

ICHEP04, Beijing, China Aug 16-22,2004
2
Bottomonium
CLEO III
n2S1LJ JLS

• 1-- (bb) states couple to virtual photon
• ?(1S)- ?(3S) too light to form B mesons
• ?ggg and qq decays dominant, but suppressed.
• ? States are narrow !
• ? EM and hadronic transitions to
  lower-lying bb states competitive
• ?(4S)?BB Weak Int. Physics

Spin-orbit3PJ?3P0,1,2
Hyperfine(spin-spin) splitting
JPC
Photon Transitions
E1 DL1, DS0
M1 DL0, DS1
? GE1 gtgt GM1
3
Detector Data Samples
Analyses presented here makeextensive use of the
excellent CsIcalorimeter, tracking and
muonsystems
?(1S)
?106
CsI 6144 crystals (barrel only) sE/E
4 at 100 MeV 2.5 at 1
GeV Tracking
?(2S)
?(3S)
4
Measurement of B(?(nS)?mm- )
ICHEP ABS10-0774

• Goal Extract Gtot.of ?(nS) .
• Gtot ltlt dEbeam ? cannot be extracted by scanning
  the resonance.
• Use Gtot Gee / Bee Gee / Bmm where
  BllB(?(nS)?mm-) (assumes lepton
  universality)
• B(?(nS)?mm- ) also important for ?(nS) EM
  hadronic BFs.
• We actually measure
• Which is related to Bmm by

Background dominated by cascade decayse.g.
?(2S)? ?(1S) ?0?0/ ? ? ?(2S)
(2.91.5) ?(3S) (2.20.7)

• ?(nS)?mm- Event Selection
• Exactly 2 back-to-back oppositely charged muons
• lt 2 showers with Egt50 MeV

?(2S) Data
?(nS)?mm- efficiency (65.20.2)
Nsh ? 2
?(2S)?mm-
Nsh lt 2

• ?(nS)?hadrons Event Selection
• gt2 charged tracks
• For Ntrklt5
• (Eccgt 0.15Ecm) (Ecclt0.75Ecm or
  EshmaxltEbeam)
• Evisible gt 0.2Ecm

?(2S)??(1S)X, ?(1S)?mm-
?(nS)?hadrons efficiency (97-98)
Mmm/Ebeam
5
Results
?(1S) ?mm in goodagreement with
previousmeasurements ?(2S), ?(3S) ?mm
significantly larger than current world average
values
B()
B()
B()
6
Electromagnetic Transitions
C. Davies, et al, PRL 92. 022001 (2004)

• Aim is to get precision measurements of masses
  and transition rates. ?Tests of LQCD
  effective theories, such as potential models or
  NRQCD.
• We present results on Inclusive Analyses of E1
  transitions
• ?(2S)?gcbJ(1P)
• ?(3S)?gcbJ(1,2P)
• Can be used to extract E1 matrix elements and
  extract relative importance ofspin-orbit and
  tensor interactions.

7
Inclusive ?(2S)?gcbJ(1P)
g
g
hadrons
Raw
hadrons
Preliminary
Backgroundsubtracted
Dominant Systematics B Shower Simulation
Fitting Eg Calorimeter calibration
8
Inclusive ?(3S)?gcbJ(1,2P)
?(3S)?gcbJ(2P)
?(3S)?gcbJ(1P)
(3S) ? ?b(1P0) ?
(3S) ? ?b(1P2) ? (3S) ? ?b(1P1) ? ?b(1PJ) ?
(1S) ?
?(1DJ)??b(1Pj) ?
Eg(MeV)
Preliminary
(2S)??b(1PJ) ?
100
50
200
Eg(MeV)
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Summary of ?(2S)? gcbJ(1P) Results (Preliminary)
?(2S)?gcb(1P1)
?(2S)?gcb(1P0)
?(2S)?gcb(1P2)
Eg
B
Gives quantitative information on the
relativeimportance of spin-orbit tensor forces
10
Summary of ?(3S)? gcbJ(2P) Results (Preliminary)
?(3S)?gcb(2P1)
?(3S)?gcb(2P0)
?(3S)?gcb(2P2)
Eg
B
11
Charmonium Production in ?(1S) Decay
ICHEP ABS10-0773

• History CDF observes J/y, y(2S) 10x, 50x
  too large.
• ? Braaten Fleming propose color-octet (CO)
  mechanism J/y produced perturbatively in CO
  state and radiates a soft-gluon
  (non-perturbatively) to become a color-singlet
  (CS) ltMEgt fit to data.
• ? Problems though J/y polarization data from
  CDF, ee-?J/yX from BaBar Belle, J/y at HERA .
• Suggestion by Cheung, Keung, Yuan If CO
  is important, the glue-rich decays of ? should
  provide an excellent labortatory for
  studying the role of the CO mechanism in y
  production. ? Distinct signatures in J/y
  momentum spectrum (peaking near endpoint).
• Li, Xie Wang show that the Y(1S)?J/yccg
  may also be important (2 charm pairs)

Li, Xie Wang, PLB 482, 65 (2000)
Cheung, Keung Yuan, PRD 54 929 (1996)
5.9x10-4
6.2x10-4
B(?(1S)?J/yX)
Soft
Hard
Momentum Spectrum
Previous CLEO measurement based on 20 J/y?mm
events B(114)x10-4
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Event Selection Signals

• Data Sample 21.2x106 ?(1S) decays
• Reconstruct J/y?mm-, ee-
• Backgrounds
• Radiative return suppressed through Ntrk,
  Egmax, and Pevmiss requirements
• Radiative Bhabha (ee only) veto events where
  either electron can form M(ee-)lt100 MeV.
• gg?ccJ Negligible after Ntrk and Pevmiss
  requirements.
• ee-?J/yX continuum Estimated using U(4S) data
  and subtracted.
• Efficiencies 40 (50) for J/y?mm (J/y?ee)
  small dependence on momentum, cosq

ee-?J/yX below Y(4S)
?(1S)?J/yX
13
?(1S)?J/yX
Continuum Background
BaBar
s(ee-?J/yX)1.90.2(stat) pb
BaBar s(ee-?J/yX)2.520.210.21 pb,
PRL87, 162002 (2001)
Belle s(ee-?J/yX)1.470.100.13 pb,
PRL88, 052001 (2002)
B(?(1S)?J/yX)(6.40.40.6)x10-4
Normalization to ?(1S) Data Luminosity
ratio Phase space ratio 0.780.13

• Spectrum much softer than CO prediction
• Somewhat softer than CS prediction
• Very different from continuum

14
First Observations/Evidence
?(1S)?ccJX
?(1S)?y(2S)X
?(4S) Continuum
CO CS both predict 20
cc1, cc2 BFs 2x CO prediction
15
Summary

• CLEO has the worlds largest sample of ?(1S), ?
  (2S), and ?(3S) data sets ?Precision
  measurements in (bb) spectroscopy (rates, masses)
  provides
• a unique laboratory for probing QCD.
• ? Glue-rich environment is ideal for studying
  color-octet predictionsRecent work also
  includes
• ? Searches/limits for M1 transitions (hb)
• ? First observation of a ?(1D) state (first new
  (bb) state in 20 years!)
• ? Measurements of new hadronic transitions
  (e.g., cb1,2(2P)?w?(1S))
• ? Searches for anomalous couplings
• Many other interesting topics are in the pipeline
• Exclusive 2g and 4g transitions in ?(3S) decays
• New measurements of Gee for ?(1S), ?(2S), ?(3S)
• ?(1S,2S,3S)?Open Charm
• ?(1S)? rp, KK, etc (rp puzzle)
• Searches for LFV

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Backup Slides
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The Physics
The ?(1S)- ?(3S) resonances are the QCD analogy
of positronium - bb are bound by the QCD
potential e.g. V(r) 4/3 ?s/r kr Large
b quark mass ? (v/c)2 0.1 ? non-relativistic to
0th order(In some models, relativistic
corrections added to non-relativisticpredictions)
In much the same way that positronium allowed
for a greater understanding of QED, the masses,
splittings between states and the transition
rates provide input into understanding
QCD. Tests of lattice QCD ?Important for flavor
physics ! Test of effective theories, such as
QCD potential models
Coulomb-like behaviorfrom 1-g exchange
Long distancebehavior, confiningk1 GeV/fm
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Electric Dipole Transitions
In the non-relativistic limit, the E1 matrix
element is spin independent.
?E1B(niS?nfP)??tot(?(nS))
Using
Uses newCLEO Gtotvalues
We can extract
After normalizing out the (2J1)E?3 between
different Js, we obtain
Comparison with various models
o predictions (non-relativistic)?
spin-averaged predictions (relativistic)

• In NR bb system, (v/c)2 0.1 ? expect ratios 1
• NR corrections O(lt20) for J0
• Also shown are (cc), which show
  sizeabledifferences (v/c)20.3 mixing between
  23S1and 13D1 states may also contribute.

time

• Relativistic corrections needed for (cc)
• In (bb) system, NR calculations in reasonable
  agreement with data.

19
Spin-Orbit Tensor Interactions
Responsible for splitting the P states ?3PJ
where
Can express MJ2 Mcog aLS - 0.4aT
MJ1 Mcog - aLS 2aT MJ0 Mcog - 2aLS -
4aT
Spin-Orbit Coeff.
Tensor Coeff.
V0 static potential V2,3 spin-dependent
potentials(both model-dependent)
Data on mass-splittings can be used to extract
aLS and aT,

• Experimentally, the mass splittings are most
  precisely determined using

Our results indicate that there is no difference
between the different radial excitations of the P
waves in (bb) system.
20
Search for hb in ?(3S) ? ?b(1S) ? and ?(2S) ?
?b(1S) ?
(2S) ? ?b(1S) ?
(3S) ? ?b(1S) ?
g
U(2S) Data
U(3S) Data
Hindered (ni?nf) M1 transition suppressed by
1/mb2 Large differences amongmodels
?b(2PJ) ? (1S) ?
?b(1PJ) ? (1S) ?
(3S) ? ?b(2S) ?
(2S) ? ?b(1S) ?
(3S) ? ?b(1S) ?
21
CUSBII(PRD46,1928(1992)) vs CLEOIII

• ?(3S)200/pb
  
  ?(3S)1300/pb
• ??10 (poor segmentation of
  calorimeter) ??60
• Also it seems that they
  had worse energy resolution.
• We are very surprised that they
  claimed comparable accuracy to ours.

(3S) ? ?b(2PJ) ?
22
ee-?J/yX using on Y(4S) Data, pJ/ygt2 GeV
23
Y(1S) Y(4S) Overlayed