CLEO Charmonium Results

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1 CLEO Charmonium Results Hanna Mahlke Cornell University Ithaca, NY Quarkonium Working Group Meeting 10/17-20/07 DESY, Hamburg

2 The Landscape All states below DD threshold observed 1-- states known best, large samples ψ(2s): 14M BES, 27M CLEO J/ψ: * on-resonance 58M BES, * from ψ(2s) π + π - J/ψ decay: BR ~32%, can tag the transition pions (CLEO: ε tag =75% 6.5M tagged J/ψ) Era of precision studies and discovery of rare phenomena in 1-- decay B(ψ(2S) γχ cj )~9%, E(γ) selects between J=0,1,2: not far behind 1 -- in statistical power Performing similar kinds of studies as for 1 -- decays Singlets less well known J PC = ψ(2s) γχ cj inclusive photon spectrum: CLEO 1.5M ψ(2s) χ χ ψ(2s) c2 c1 γχ χ cj c0 Background removed QWG 10/18/07 H. Mahlke, CLEO 2

3 New CLEO charmonium results discussed in other presentations: ψ(2s) γ η c (1S): Exclusive and inclusive η c (1S) decays η c (1S) line shape BR(ψ(2S) γ η c (1S)) Ryan Mitchell s talk (Wednesday) ψ(2s) π 0 h c, h c γη c (1S): Exclusive and inclusive η c (1S) decays M(h c ) and hyperfine splitting Product branching fraction BR(ψ(2S) π 0 h c ) BR(h c γη c (1S) ) Kam Seth s talk (Friday) QWG 10/18/07 H. Mahlke, CLEO 3

4 χ cj Decays to γγ ππ, KK η( )η( ) baryon/anti-baryon multibody final states Detailed comparisons between decay modes allow to assess the role of the color octet configuration 27M ψ(2s) decays over 2M χ cj produced for J=0,1,2 each Can probe exclusive decays down to BR ~10-4 Exploit kinematic constraints in a fit of measured momenta/ energies to m(ψ(2s)), don t need to constrain to m(χ cj ) in addition

5 χ cj 2 hadrons Glue-rich environment different from 1 states χ cj = cc many theory predictions «experimental BR results Accurate prediction of 2-hadron decay rates of 3 PJ states rely on understanding of the role of the color octet contribution: γ E1 Analysis relies on identification of all decay products and kinematic fit to initial ψ(2s) four-momentum. Is that all? Known 2-body modes amount to only a few percent of χ cj decays e - ψ e + Next: 14 two-body decay modes of χcj (13x hadronic + γγ) QWG 10/18/07 H. Mahlke, CLEO 5 h χ c h

6 χ cj MM, M=π,K ππ, KK (χc1 PP is forbidden) χc0 χc2 Previous measurements had uncertainties of 10% or larger Clean signals seen in CLEO data CLEO uncertainties <=10% QWG 10/18/07 H. Mahlke, CLEO 6

7 χ cj MM, M=π,K Branching Fraction Results: CLEO preliminary BR (10-3 ) π + π π 0 π 0 K + K - K S K S Belle PLB 651, 15 (2007) χ c0 χ c2 Ratios: PDG CLEO 27M (total error) PDG CLEO 27M (total error) 4.9± ±0.11±0.20±0.32 (6%) 1.8± ±0.04±0.06±0.10 (8%) χ c0 0.54±0.03 Belle: K s K s /K + K ± ±0.24 π 0 π 0 /π + π ± ±0.13 K s K s /π + π ±0.03 Belle: 0.46± ±0.03 Belle: 0.40± ± ±0.07±0.16±0.15 (8%) 1.1± ±0.03±0.05±0.04 (10%) χ c2 0.47±0.05 Belle: 6.0± ±0.11±0.29±0.32 (7%) 0.9± ±0.03±0.05±0.07 (8%) 2.8± ±0.01±0.15±0.17 (7%) 0.7± ±0.03±0.02±0.03 (7%) Errors: (stat.) ± (syst.) ± (BR(ψ γχcj)) QWG 10/18/07 H. Mahlke, CLEO 7 CLEO, PRD 70, (2004) CLEO improves upon precision, is consistent with Belle and with isospin counting expectations K S K S : K + K - = 1:2, π 0 π 0 : π + π - = 1:2

8 χ cj η ( ) η ( ) η( )η( ) B(J/ψ ωf0(1710)) ~ B(J/ψ φf0(1710)): f0(1710) is thought to be largely ss naively expect φ preferred over ω ω Suggestive of large OZI violating effects in J/ψ decay?...glueball mixing? F. Close,Q. Zhao, PRD 71, (2005) Look for similar effects in χc η( )η( ) Use the factorization scheme proposed by Q. Zhao (PRD 72, (2005)) ηη can only go through DOZI, χ c1 PP is forbidden r = relative strength between singly-ozi and doubly-ozi suppressed transition amplitudes QWG 10/18/07 H. Mahlke, CLEO 8 SOZI DOZI

9 χc0 χc2 χ cj η ( ) η ( ) ηη ηη 1 st obs. branching fractions χ c0 ηη and η η improved η η χ c2 ηη observed (1 st time) Still no signal for ηη CLEO, PRD 70, CLEO Preliminary Errors: (stat.) ± (syst.) ± (B(ψ γχ cj )) Uses similar analysis technique as for other two-body modes BR, 10-3 χ c0 χ c2 ηη 3.18±0.13±0.18± ±0.05±0.03±0.03 η η <0.25 (90% CL) <0.05 (90% CL) η η 2.12±0.13±0.11±0.11 < 0.10 (90%CL) QWG 10/18/07 H. Mahlke, CLEO 9

10 χ cj η ( ) η ( ), comparison with theory Predicted dependence of BR on r (DOZI/SOZI) Q. Zhao (PRD 72, ) (2005) CLEO Preliminary Results Result: Data suggest small if any contribution for DOZI decays in 0 -+ channel. QWG 10/18/07 H. Mahlke, CLEO 10

11 χ cj γγ Experimental technique similar to that for χ cj decays to 2 hadrons c c ψ(2s) χ cj γ E1 γγ Fit E1 photon or m(γγ) distribution after selecting χ cj γγ Determine QED background shape from continuum and ψ(3770) samples χ cj γγ is pure QED in first approximation Decay rates relativistic and radiative corrections (significant in the charmonium system!) Γ(χ γγ) measurements range from 2-4keV, with smallest error 0.6keV χ c2 335 ± M ψ(2s) χ c0 212 ± 31 (background subtracted) CLEO Preliminary Eγ [GeV] QWG 10/18/07 H. Mahlke, CLEO 11

12 χ cj γγ γγ PDG ave CLEO Preliminary Results Errors: (stat.) ± (syst.) ± (PDG Input) Also limit the forbidden process: Most precise measurement In the nonrelativistic limit: R=4/15=0.27 QWG 10/18/07 H. Mahlke, CLEO 12

13 Two-photon widths comparison with theory * -- includes relativistic corrections -- includes radiative corrections Fajfer CLEO preliminary QWG 10/18/07 H. Mahlke, CLEO 13

14 χ cj baryon antibaryon χc0 χc2 χc1 ~5σ ~3σ ΛΛ: only direct production; kin. fit weeds out Σ 0 Λγ pp and ΛΛ have been seen before; puzzle over relative production rates: Color Octet Model reproduces pp rates: Extend to ΛΛ (J=1,2): expect ΛΛ:pp = 1:2, see ΛΛ»pp forj=0,1,2 BES PRD 67, (2003) χ cj other baryon pairs? CLEO studied B=p,Λ,Σ,Ξ some new discoveries QWG 10/18/07 H. Mahlke, CLEO 14

15 χ cj baryon antibaryon CLEO preliminary BR, 10-5 (UL at 90% CL): Errors: (stat.) ± (syst.) ± (BR(ψ γχcj)) PDG CLEO χ c0 χ c1 χ c2 pp ΛΛ 22.5± ±1.5±1.5±1.3 47± ±3.6±2.3±1.7 Σ 0 Σ ±5.6±2.5±2.2 Σ + Σ ±5.7±4.9±1.7 Ξ Ξ < ±6.0±3.8±2.6 Ξ 0 Ξ ±7.0±3.2± ± ±0.8±0.4±0.5 26± ±1.8±0.7±0.7 - <4 - <6 <34 8.6±2.2±0.6±0.5 - <5 6.8± ±0.8±0.4±0.5 34±17 17±2.2±1.1±1.1 - <6 - <6 < ±1.9±1.0±0.9 - <9 CLEO, PRD 70, (2004) New and/or improved branching fraction measurements Lambda production, as seen by BES, not found to be suppressed relative to protons (prediction only for J=1,2) QWG 10/18/07 H. Mahlke, CLEO 15

16 3M ψ(2s) χ cj h + h - h 0 π 0 CLEO preliminary, 3M ψ(2s) Clear signals seen M(4hadrons) (GeV/c 2 ) Survey of four-body decays Resonant substructure is important for 4π and KKππ, (ρππ or K*Kπ or KKρ or...) Branching fractions and contributions from intermediate resonances determined Isospin relations: ρ + π π 0 = ρ 0 π + π? K*Kπ modes: Expect 1:2 CLEO preliminary QWG 10/18/07 H. Mahlke, CLEO 16

17 χ cj h + h - h 0 π 0 branching fractions CLEO preliminary, 3M ψ(2s) Sum: 7.2% 2.4% 3.7% QWG 10/18/07 H. Mahlke, CLEO 17

18 Ties to lighter systems η properties Resonances observed in χ cj multibody decays

19 γγ η branching ratios 0.12 J/ψ momentum, GeV cos θ (EHi) +1 3π 0 l + l - J/ψ 27M ψ(2s), ψ(2s) B(ψ(2S) ηj/ψ) = 3.1%, B(J/ψ l + l - ) = 12%, η π + π γ π + π - π 0 e + e - γ Fully reconstruct five final states: γγ + 3π 0 + π + π - π 0 + π + π γ + e + e - γ % Constrain l +, l - J/ψ, constrain J/ψ, η products ψ(2s) Excellent data/mc agreement Measurement of ratios allow cancellation of systematics QWG 10/18/07 H. Mahlke, CLEO 19

20 η branching fractions CLEO-c Other l + l - J/ψ 27M ψ(2s), ψ(2s) B(ψ(2S) ηj/ψ) = 3.1%, B(J/ψ l + l - ) = 12%, η R / R central (Other) CLEO-c PDG Global Fit Fully reconstruct five final states: γγ + 3π 0 + π + π - π 0 + π + π γ + e + e - γ % Follow PDG procedure: sum of the above five modes is ~ 100% build absolute Br s from ratios π + π - γ and e + e - γ: 3σ deviation Γ(CLEO) / Γ(PDG06) CLEO, PRL 99, (2007) or arxiv: QWG 10/18/07 H. Mahlke, CLEO 20

21 Invariant mass of η decay products: γγ CLEO ψ(2s) ηj/ψ 27M ψ(2s) η Mass 3π 0 CLEO: M(η) = ± ± MeV PRL 99, (2007) (arxiv: ) KLOE: M(η) = ± ± MeV arxiv: (LP07 contribution) π + π - π 0 π + π - γ M(CLEO) M(PDG06) (MeV) QWG 16k 10/18/07 fully reconstructed events H. Mahlke, CLEO 21

22 Interest: Branching fractions Likely a lot Substructure analysis CLEO studied h + h - h 0 in 3M decays, sufficient events for simple Dalitz analysis in ηπ + π -, K + K - π 0, and K - K S π + - model describes dominant features, but ignores interference 20% systematic uncertainty h + h - h 0 π 0 also looked promising Enlarged data sample will allow to refine technique and to study other multibody modes χ cj multibody decays 3M psi(2s) CLEO PRD 75, (2007) QWG 10/18/07 H. Mahlke, CLEO 22

23 χ cj KKππ 27M ψ(2s) - first look Can study charged and neutral pion and kaon combinations χ cj decays to all combinations from all three J states visible, well separated QWG 10/18/07 H. Mahlke, CLEO 23

24 χ c0 from 27M ψ(2s) - first look Substructure: M(π + π ) m(k + K - ) KK and ππ χ c0 No f 0 (980) Complementary and different structure in six KKππ submodes No ρ (K 1 feeddown) Looking at different isospin configurations allows to disentangle components QWG 10/18/07 H. Mahlke, CLEO 24

25 Summary Charmonium is a testing ground for many areas of QCD: Spectroscopy of charmonium states Decay of charmonium states Production of lighter systems New results cascading down on the community need to sort, digest, understand (exp + th!) At today s data sample sizes, sensitive to small effects discovery and precision studies CLEO s 27M ψ(2s) dataset will lay the foundation for future BES studies QWG 10/18/07 H. Mahlke, CLEO 25

26 Backups

27 χ c0 χ c2 1+cos 2 theta 1+1/13*cos 2 theta χ c2 χ c2 chicj information: pion and kaon samples combined χ c2 Meson theta in chic2 rest frame χ c2 Meson theta in lab frame Meson phi in lab frame QWG 10/18/07 H. Mahlke, CLEO 27