Decays at CLEO

Decays at CLEO

Steve BluskSyracuse University

for the CLEO Collaboration

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

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

ICHEP’04, Beijing, China Aug 16-22,2004

BottomoniumBottomonium

JPC

1-- (bb) states couple to virtual photon

(1S)- (3S) too light to form B mesonsggg and qq decays dominant, but suppressed. States are narrow ! EM and hadronic transitions to lower-lying bb states competitive

(4S)BB; Weak Int. Physics

n2S+1LJ J=L+S

Photon TransitionsE1: |L|=1, S=0: 3 2| | | |f f f fE n L R n L

M1: L=0, |S|=1: 3 2 2( / ) | | | |b f f f fE m n L R n L E1 >> M1

Hyperfine(spin-spin) splitting

Spin-orbit3PJ3P0,1,2

CLEO III

Detector & Data Samples

(1S)

(2S)(3S)

106

Analyses presented here makeextensive use of the excellent CsIcalorimeter, tracking and muonsystems

CsI: 6144 crystals (barrel only): E/E ~ 4% at 100 MeV ~2.5% at 1 GeV

Tracking

Measurement of B((nS)) Goal: Extract tot.of (nS) .

tot << Ebeam cannot be extracted by scanning the resonance. Use: tot= ee / Bee = ee / B where Bll=B((nS)+-); (assumes lepton universality) B((nS)) also important for (nS) EM & hadronic BF’s.

We actually measure:

Which is related to B by:

( ) ( )/ /had nS nS hadronsN N B

/(1 3 )B B B

(nS) Event Selection Exactly 2 back-to-back oppositely charged muons < 2 showers with E>50 MeV

(nS)hadrons Event Selection >2 charged tracks For Ntrk<5: (Ecc> 0.15Ecm) & (Ecc<0.75Ecm or Esh

max<Ebeam) Evisible > 0.2Ecm

(nS) efficiency: (65.2±0.2)%

(nS)hadrons efficiency: (97-98)%

Background dominated by cascade decays:e.g. (2S) (1S) 00/ (2S) : (2.9±1.5)% (3S) : (2.2±0.7)%

Nsh < 2Nsh 2

M/Ebeam

(2S)(1S)X, (1S)

(2S)

(2S) Data

ICHEP ABS10-0774

B(%) B(%)B(%)

Results(1S) (2S) (3S)

N 344,908 ± 2485 119588 ± 1837 81179 ± 2660

0.652 ± 0.002 0.652 ± 0.002 0.652 ± 0.002

Nhad 18,957,575 ± 11729 7,838,270 ± 8803 4,641,369 ± 12645

had 0.979 ± 0.016 0.965 ± 0.013 0.975 ± .014

Interference corr. 0.984 0.961 0.982

B (%) 2.49 0.02 0.07 2.03 0.03 0.08 2.39 0.07 0.10

tot (keV) 52.8 ± 1.8 29.0 ± 1.6 20.3 ± 2.1

PDGtot (keV) 53.0 ± 1.5 43.0 ± 6.0 26.3 ± 3.4

(1S) in goodagreement with previousmeasurements

(2S), (3S) significantly larger than current world average values

Electromagnetic

Transitions

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)bJ(1P) (3S)bJ(1,2P)

Can be used to extract E1 matrix elements and extract relative importance ofspin-orbit and tensor interactions.

C. Davies, et al, PRL 92. 022001 (2004)

Inclusive (2S)bJ(1P)

e+e-

hadrons

hadrons

(2S) Branching

Fraction (%)Photon energy

(MeV)

b0(1P) 3.750.120.47

162.560.190.42

b1(1P) 6.930.120.41

129.580.090.29

b2(1P) 7.240.110.40

110.580.080.30

Raw

Backgroundsubtracted

hadrons

Preliminary

Dominant Systematics B: Shower Simulation & Fitting E: Calorimeter calibration

(3S) Branching Fraction (%)

Photon energy(MeV)

b0(2P) 6.770.200.65121.550.160.4

6

b1(2P) 14.540.180.73

99.150.070.25

b2(2P) 15.790.170.73

86.040.060.27

b0(1P) 0.300.040.10 -

Inclusive (3S)bJ(1,2P)

(2S)b(1PJ) (1DJ)b(1Pj)

(3S) b(1P0) (3S) b(1P2) +

(3S) b(1P1) +

b(1PJ) (1S)

(3S)bJ(2P)

(3S)bJ(1P)

100 50 200EMeV

EMeVPreliminary

Summary of (2S) bJ(1P) Results (Preliminary)

EE

BB

(2S)b(1P2) (2S)b(1P1) (2S)b(1P0)

2 1

1 0

0.57 0.01 0.01m m

rm m

Gives quantitative information on the relativeimportance of spin-orbit & tensor forces

Summary of (3S) bJ(2P) Results (Preliminary)

EE

BB

(3S)b(2P2) (3S)b(2P1) (3S)b(2P0)

2 1

1 0

0.58 0.01 0.01m m

rm m

Charmonium Production in (1S) Decay History: CDF observes J/, (2S) ~10x, 50x too large. Braaten & Fleming propose color-octet (CO) mechanism; J/ produced perturbatively in CO state and radiates a soft-gluon (non-perturbatively) to become a color-singlet (CS); <ME> fit to data. Problems though: J/ polarization data from CDF, e+e-J/+X from BaBar & Belle, J/ 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 production. Distinct signatures in J/ momentum spectrum (peaking near endpoint).

Li, Xie & Wang show that the Y(1S)J/+ccg may also be important (2 charm pairs)

Li, Xie & Wang, PLB 482, 65 (2000)

Cheung, Keung & Yuan, PRD 54 929 (1996)

B((1S)J/+X) 6.2x10-4 5.9x10-4

Momentum Spectrum Soft Hard

Previous CLEO measurement based on ~20 J/ events: B=(11±4)x10-4

ICHEP ABS10-0773

Event Selection & Signals Data Sample: 21.2x106 (1S) decays Reconstruct J/, e+e- Backgrounds:

Radiative return: suppressed through Ntrk, Emax, and Pev

miss requirements Radiative Bhabha (ee only): veto events where either electron can form M(e+e-)<100 MeV. cJ: Negligible after Ntrk and Pev

miss requirements. e+e-J/+X continuum: Estimated using (4S) data and subtracted.

Efficiencies: ~40% (~50%) for J/ (J/ee); small dependence on momentum, cos

(1S)J/+X e+e-J/+X below Y(4S)

(1S)J/+X

B((1S)J/+X)=(6.4±0.4±0.6)x10-4

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

Continuum Background

(e+e-J/+X)=1.9±0.2(stat) pb

BaBar(e+e-J/+X)=2.52±0.21±0.21 pb, PRL87, 162002 (2001) Belle(e+e-J/+X)=1.47±0.10±0.13 pb,

PRL88, 052001 (2002)

Normalization to (1S) Data * Luminosity ratio * Phase space ratio: 0.78±0.13

9.46 10.56 2

/ /* / (10.56 / 9.46)GeV GeV

e e J X e e J X

BaBar

First Observations/Evidence(1S)(2S)+X (1S)cJ+X

( (1 ) (2 ) )0.41 0.11 0.08

( (1 ) / )

B S S X

B S J X

2

1

0

( (1 ) )0.52 0.12 0.09

( (1 ) / )

( (1 ) )0.35 0.08 0.06

( (1 ) / )

( (1 ) )7.4

( (1 ) / )

c

c

c

B S X

B S J X

B S X

B S J X

B S X

B S J X

CO & CS both predict ~20%

c1, c2 BF’s ~2x CO prediction

(4S) Continuum

SummaryCLEO has the world’s 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 predictions

Recent work also includes: Searches/limits for M1 transitions (b) First observation of a (1D) state (first new (bb) state in 20 years!) Measurements of new hadronic transitions (e.g., b1,2(2P)(1S)) Searches for anomalous couplings Many other interesting topics are in the pipeline Exclusive 2 and 4 transitions in (3S) decays New measurements of ee for (1S), (2S), (3S) (1S,2S,3S)Open Charm (1S) , K*K, etc (“puzzle”) Searches for LFV …

Backup Slides

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, confiningk~1 GeV/fm

Electric Dipole Transitions

2321 )12(

27

4)( SnrPnEJePnSn ifQfiE

After normalizing out the (2J+1)E3 between

different J’s, we obtain:

b(2P):(J=2) / (J=1)

(J=0) / (J=1)

(J=0) / (J=2)

1.000.010.05

0.760.020.07

0.760.020.09

b(1P):(J=2) / (J=1)

(J=0) / (J=1)

(J=0) / (J=2)

1.010.020.08

0.820.020.06

0.810.020.11

c(1P):(J=2) / (J=1)

(J=0) / (J=1)

(J=0) / (J=2)

1.500.020.05

0.860.010.06

0.590.010.05

In the non-relativistic limit, the E1 matrix element is spin independent.

In NR bb system, (v/c)2~ 0.1 expect ratios ~ 1 NR corrections O(<20%) for J=0

Also shown are (cc), which show sizeabledifferences (v/c)2~0.3; mixing between 23S1and 13D1 states may also contribute.

Comparison with various models

E1=B(niSnfP)tot((nS))Using:Uses newCLEO tot

valuesWe can extract | | f in P r n S

Relativistic corrections needed for (cc)

In (bb) system, NR calculations in reasonable agreement with data.

o = predictions (non-relativistic)▲ = spin-averaged predictions (relativistic)

time

Spin-Orbit & Tensor InteractionsResponsible for splitting the P states 3PJ

Can express:

MJ=2 = Mcog + aLS - 0.4aT

MJ=1 = Mcog - aLS + 2aT

MJ=0 = Mcog - 2aLS - 4aT

where

2 02

1 1| (2 0.5 ) |LS

b

da nP V V nP

m R dR

32

1| |

12Tb

a nP V nPm

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

01

12

mm

mmr

CLEO3 CLEO2

r (1P) 0.570.010.01 0.540.020.02

r (2P) 0.580.010.01 0.570.010.01

Our results indicate that there is no difference between the different radial excitations of the P waves in (bb) system.

Search for b in (3S) b(1S) and (2S) b(1S)

(2S) b(1S) (3S) b(1S)

b(2PJ) (1S)

(2S) Data

b(1PJ) (1S)

Hindered (ninf) M1 transition suppressed by 1/mb

2

Large differences amongmodels

(3S) Data

(3S) b(2S) (2S) b(1S) (3S) b(1S)

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)

e+e-J/+X using on Y(4S) Data, pJ/>2 GeV

Y(1S) & Y(4S) Overlayed