Charmonium Results from CLEO

Y. Kubota representing the CLEO collaboration

18 Aug 2004

18 August 2004 CLEOc Charmoium results 2

Outline

• Motivation(2S)cJ branching fractions

c(’) masses and (2S)c branching

fractions

• X(3872) search (preliminary)

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Motivation

• Better understanding of QCD– Needed for better measurements of electroweak

processes– Good testing ground of LQCD– Good practice to understand future physics,

which involves strong coupling (Lepage)

• Heavy quarkonia– relativistic effects are smaller

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cJ

cJ:

– well established.• E1 transitions from (2S) (transition rates) fusion production (Γγγ’s)

• pp annihilation (masses, widths)

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c(’)

c: – well established.

– M1 transition from J/ & (2S) (mass, transition rates) fusion production (mass, width, Γγγ’s)

– pp annihilation (mass, width)

c’:

– Established two years ago by Belle (B decays, etc.), and CLEO and Babar ( fusion production)

– Crystal Ball result using M1 transition from (2S) is most likely false.

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Photon Spectrum (2.7 pb-1)

• No 0 suppression

• cos >0.5 – used in analysis

• Max 0 suppression

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c Fit results

Solid: Signal+backgroundDotted: generic background onlyDashed: generic + MIP background

Background subtracted

Systematic errors:Event selection,Fitting,0 suppression

0

10000

MIP

J/c

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(2S)cJ Branching Fractions

• CLEOc & C-Ball agree well.• Ratios of BF’s very close to 1

– within 3-8% systematic errors– NRQCD expectations ~ (2J+1)Eγ

3 – Relativistic effects important?

BF (%) c2 c1 c0

CLEOc 9.33±0.14±0.61 9.07±0.11±0.54 9.22±0.11±0.46

Crystal Ball 8.0±0.5±0.7 9.0±0.5±0.7 9.0±0.5±0.8

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c Fit results

Solid: Signal+backgroundDotted: generic background only

Background subtracted

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c mass and (2S)c BF

• mc = (2970±7) MeV

– Consistent w/ world average of ~2980 MeV.

• B((2S)c) = (0.32±0.04±0.06)%– Sensitive to relativistic corrections.

– Crystal Ball obtained (0.28±0.06)% for Γc =

(11.5±4.5)MeV.

– CLEOc would have given (0.25±0.06)% for this Γc –

entirely consistent.

• About expected level by theories.

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(2S)c(2S)

• No trace of this transition at Eγ = 91 MeV• BF < 0.2% at 90% C.L.• C-Ball presented BF ~ (0.2-1.3)% with 95%

C.L.• Given the mass & width of c(2S) of 3638

and 25 MeV at recent experiments (Belle, CLEO, Babar), we expect Eγ = 47 MeV and width ~ 10 MeV

• No meaningful sensitivity exists at this energy and width.

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X(3872): background

• Found by Belle in B decays

• Confirmed by CDF and D0 – general hadronization

• Mass = 3872 MeV

• Width – smaller than resolution ~ 2 MeV

• Decays to π+π–J/ψ; no report on π0π0J/ψ

• Has not been found in γχ, γJ/ψ, DD, D0D0π0

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What is X(3872)?• Charmonium?

– From narrow width,– 13D2(2– –), 13D3(3– –), 21P1(1+–) all C = –, or– 11D2(2–+), 23P1(1++) all C = +

• DD* molecule?– Close to DD* threshold and from lack of π0π0J/ψ

decays– ρ0J/ψ decay?– Then X(3872) will most likely be 0–+ or 1++.

• Glueball?– Three-gluon glueball of 1– – at m = 3850 MeV

predicted.

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JPC determination• It will be useful to know what JPC of X(3872)

is.

• BES showed that its production in ISR (e+e–

γe+e–γX(3872) is invisible (ECM = 4 GeV)

– Γee×B(π+π–J/ψ) < 10 eV (90% C.L.)

– JPC 1– –?

• CLEO seeks X(3872) in 15 fb-1 of data using– γγ fusion (C = + & J = even only)

– ISR (ECM = 10 GeV)

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Event characteristics

• Missing momentum/energy in the beam directions– In γγ fusion, missing momentum ~ 0– In ISR, missing momentum ~ missing energy

• Missing momentum perpendicular to the beam is small

• 4 charged particles• No neutral energy

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Result• Clear peak

for ψ(2S)

• No event for X(3872)

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Distinguishing γγ fusion from ISR• Due to the difference in the beam-direction

motion of X(3872) candidates, we can distinguish the two production mechanism.

ISR γγ fusion

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Final results

• (2J+1)Γγγ×B(Xπ+π–

J/ψ) < 12.9 eV (90% C.L.)

• Γee×B(π+π–J/ψ) < 8.0 eV (90% C.L.)

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Interpreting results• (2J+1)Γγγ×B(Xπ+π–J/ψ) < 12.9 eV

– Assume B(BKX) ~ B(BKψ(2S)) – B(Xπ+π–J/ψ) = 2% – (2J+1)Γγγ < 0.6 keV

– Compare it to (2J+1)Γγγ for ηc, χc0, and χc2.

• 7.4 keV (ηc); 2.6 keV (χc0); 2.6 keV (χc2)

• Γee×B(Xπ+π–J/ψ) < 8.0 eV (90% C.L.)

– This is less than 1% of ψ(2S) production in ISR events.

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Summary

• Precise measurements of rates for (2S)cJ and

(2S)c

• Limit on (2S)c(2S)

• Upper limits on X(3872) productions in– ISR– γγ fusion