CLEOIII Upsilon results

CLEOIII Upsilon results• In principle, includes:• CLEO-III dipion transitions between vectors

– Complements CLEO05 results on transitions between L=1 P-states

• High-precision measurement of dielectronic width of Y(1S), (2S) (3S)

• Many radiative results:– Observation of exclusives already presented:

– Upper limits on and ’ modes

– UL on multibody modes (>=4 charged tracks)

– Comparison of inclusive quark/gluon production in radiative decays of Y vs. qq+photon (ISR)

CLEOIIICLEAN signals, angular analysis underway.

Dipion transitions

• Renewed interest in `double-bump’ structure in (3S)(1S) following BaBar observation of 4S(nS)

Goal: spin/parity analysis across invariant mass to determine whether low-mass bump is sigma0 – if not, what is it?

Exclusives: Multibody modes

• Exclusive radiative events‘bumps’ in the inclusive (scaled to Ebeam) photon spectrum (assume narrow recoil object)• We perform a series of fits to the inclusive photon spectra as a function of E in order to set an E-dependent upper limit on these radiative events.

• Nota bene: ‘bumps’ in the inclusive photon spectra can also be caused by continuum threshold effects (ccbar, e.g.)

*→+, →4 MC

An example, albeit exaggerated, of signal . . . (10-2)

Method (Fitting Spectrum)

• We fit each step to a Gaussian+Chebyshev polynomial

• Step along the photon spectra with the Gaussian mean

• Fix Gaussian sigma at each step to be the detector resolution (~1% @ 5 GeV)

• Looking for narrow resonances so the measured photon energy dist. should be Gaussian with Gaussian width E.

Efficiencies (*→+, →?)

4 592% 2p2K0 505% 480 602%

4K 502% 22K0 532% 6 743%

4p 672% 420 591% 6K 684%

2p2 623% 4K20 492% 6p 524%

2p2K 562% 4p20 632%

22K 533% 2p220 635%

40 602% 2p2K20 572%

4K0 482% 22K20 543%

4p0 652% 440 572%

2p20 545% 460 602%

Worst

Phase Space

High Mult.

All limits on the order of 10-4

•Embed signals at a given level into data. •We then apply our procedure to the resulting spectra

• We construct all signals above our upper limit floor (~10-4) in our accessible recoil mass range

In/Out and Sensitivity Check

A(M

)+

1.6

45*

A(M

)

dN

/d(A

/A)

(<

(1S

))

A/A

Check of pulls:

Continuum data

Results

• Our sensitivity is of order 10-4 across all accessible values of M

• Above the threshold for any known B((1S)→+pseudoscalar, pseudoscalarh+h-h+h-+neutrals)

• We measure for all M:B((1S)→+,4 charged tracks) < 1.05 x 10-3

B((2S)→+,4 charged tracks) < 1.65 x 10-3


Results (2)

• Restricting M to 1.5 GeV < M < 5.0 GeV we measure:B((1S)→+,4 charged tracks) < 1.82 x 10-4



• We report these upper limits as a function of recoiling mass M (see conf. Paper)• B.R.’s are all ~10-4. • N.B. Not in conflict with any observed two-body radiative decays to-date (due to 4-charged track requirement here)

Many modes!

Dedicated search for 1S and 1S’;

Observed in J/psi decay at 10-4 and 4.7x10-4 level

Only upper limits quoted at this time…

Suggests dedicated search for (1S)c?

Quarks v. Gluons

•1981 (CESR): e+e- collisions (ECM ~ 10 GeV) produce ; ggg allows high-statistics study of gluon fragmentation

•Isolate gluons: ggg decay of Isolate quarks: fragmentation

•1984 Find: more baryons/event in ggg decay than

•Weakness: 3 partons (ggg) vs. 2 partons ( ) 3 strings (ggg) vs. 1 string ( )

•Solution: decay of vs. decay of continuum

qq

qq

qq

gg

qq

qq

• e+e- Z0

(LEP)

Y(1S)3gluons, but also 2-gluon source:

•e+e- (CLEO)

• e+e- (1S) (CLEO)

)(qq

gg

gqq

ggg

Z0

gqq

Data Sets

Data Set Luminosity (1/fb) ECM (GeV)

1S 1.19 9.46

2S 1.07 10.02

3S 1.42 10.36

4S 5.52 10.58

Below 4S 2.10 10.55Note that for 2S and 3S have not corrected for cascades:

(2S) (1S) + X(3S) (2S) + X (3S) (1S) + X

Are included as consistency checks, but have subtractions and corrections that have not been included.

Method: vs. qqggg

•Bin according to particle momentum

•Count N(Baryon) per bin and normalize to hadronic event count

•Enhancement is:

Continuum-subtracted Resonance Yield

Continuum Yield

Enhancement = 1.0 Particle is produced as often on resonance as on continuum

Method: vs.

•Bin particle yield recoiling against high-E photon according to tagged photon momentum

•Count N(Baryon) per bin and normalize to photon count in that bin

•Enhancement is:

Continuum-subtracted Resonance Yield

Continuum Yield

Enhancement = 1.0 Particle is produced as often on resonance as on continuum

qqgg

Λ p p φ

Detector and Generator Level: ggg

manageable bias; use correction factor where appropriate; discrepancy in/out used for systematics

•Successfully reproduce CLEO84 indications of baryon enhancement in 1S (ggg) vs. CO ( ) fragmentation

•Comparison of baryon production in 1S ggγ vs. e+e- (comparing two gluon to two quark fragmentation)

-1S gg baryons shows much reduced enhancement relative to baryons -Effect not reproduced in JETSET MC

Proton f2 results

qq

qq

qq

Ggg/qqbar Ggγ/qqbargamma Ratio

p 1.30 ± 0.01 1.10 ± 0.02 ~ 1.2

Antip 1.33 ± 0.01 1.19 ± 0.03 ~1.1

Λ 2.56 ± 0.02 1.97 ± 0.03 ~1.3

φ 0.85 ± 0.03 1.1 ± 0.3 ~0.8

f2 0.66 ± 0.04 1.4 ± 0.9 ~0.5

Deuteron Production (Preliminary)

B(1S(ggg+ggd+X=

2.86(0.30)x10-5

Per event enhancement of deuteron production in gluons vs. quarks ~12.0(2.0). Also: note 1Spsi >> continuumpsi

Summary

• Radiative decays (in general) continue to be more elusive than for J/psi

• Baryon coupling to 3-gluons confirmed (even larger for deuterons!); enhancement in 2-gluons mitigated.

• Ramping down these efforts (CLEO-III CLEOc)

• Future improvements/results hopefully to emerge from B-factories with dedicated Upsilon running

• Thanks to everyone who did the work!

•Reproducing CLEO84 indications of baryon enhancement in 1S(ggg) vs. CO ( ) fragmentation

•New comparison of baryon production in 1S ggγ vs. e+e- comparing two gluon to two quark fragmentation -First time such a comparison has been made

•Essential results: -1S gg baryons shows much reduced enhancement

relative to baryons -Effect not reproduced in JETSET MC

•Additional cross-checks (2S, 3S, comparison with mesons) included

Overview

qq

qq

qq

p and p: 2S/3S data corrected

Data Results: ggg

Λ: 2S corrected

Data Results: ggγ

Method (Extracting Limit)

• Plot the gaussian area A(x) from fits to inclusive photon spectra

• Convert into an upper limit contour with height=A(x)+1.645*A(x)

• A(x) is the Gaussian fit sigma

• Negative points → 1.645*A(x)

• Divide on-resonance fits by efficiency corrected number of (1S), (2S) and (3S) events (-1events) •Divide off-resonance fits by luminosity of off-resonance running and derive xsct UL’s

• Note: +f2(1270) will not show up in this analysis since B (f2 4 tracks) is approximately 3%• B ((1S)+, +-, +-0) << 10-4

The M-Dependent Upper Limits

CHECK OF PULL DISTRIBUTIONS

Fragmentation Models

•Simplistically there are two models: Parton vs. String

•Parton: g or q radiates a new particle

•String: g and q are connected by a string (gluon). Particles move apart; string stretches and breaks; forms new particles

•String model is what is in JetSet MC (CLEO: Jetset 7.4 PYTHIA) Parameters tuned to √s = 90 GeV LEP Data

e+

e-

q

q

Data Results

•Show data and detector level MC enhancements for both ggg and ggγ

•“Corrected” data and generator level MC enhancements for those with a low CL fit.

•Systematic errors have been introduced based on the correction factor.

Λ p p φ f2

1

Data Results: Momentum-Integrated

Λ p p φ f2

1

Documents

CLEOIII Upsilon results