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Hadron Physics from -Charm factories

Hadron Physics from -Charm factories. Yangheng Zheng Graduate University of Chinese Academy of Sciences Sep. 21, 2009. Outline. Recent selected hadron physics results from CLEOc and BESII Charmonium physics Light hadron spectroscopy

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Hadron Physics from -Charm factories

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  1. Hadron Physics from -Charm factories Yangheng Zheng Graduate University of Chinese Academy of Sciences Sep. 21, 2009

  2. Outline • Recent selected hadron physics results from CLEOc and BESII • Charmonium physics • Light hadron spectroscopy • BESIII/BEPCII experiment status and preliminary results • Summary

  3. Topics are not covered • Open charm physics (D, Ds decays) • Search for rare and forbidden decays • Earlier physics results from t-Charm colliders • I apologize for not covering many important results

  4. Data samples • CLEOc • ~27 million(2S) decays • ~5.4 million DDbar events (818 pb-1) • ~0.55 millione+e-→ DsDs* events (600 pb-1) • BESII • ~14 million(2S) decays • ~58 millionJ/ decays • BESIII • ~110 million(2S) decays • ~200 millionJ/ decays

  5. Charmonia physics • What to measure? • Production, decays, transition, spectrum • For what ? • A lab for pQCD and non-pQCD • Calibrate LQCD • How quarks form a hadron ? • Why at tau-charm factories? • A clean environment • Tagging possible • Abundantly produced Examples of Interesting problems: • rp puzzle • Missing states ? • Mixing states ? • New states above open charm (X,Y,Z,…)

  6. J/, ’→c and the c lineshape 12 Exclusive hc from J/ψ  γηc PRL 102, 011801 (2009) BW* E3g BW backgrounds PRD 73, 054005 (2006) CLEO inclusive photon from ψ(2s) γηc B(ψ(2S)→γηc)=(4.32±0.16±0.60)×10−3 inclusive B(J/ψ→γηc)/B(ψ(2S)→γηc) =(4.59±0.23±0.64) exclusive  B(J/ψ→γηc)=(1.98±0.09±0.30)% Line: shape from exclusive Lineshapes in exclusive channel at BESIII, and energy dependent ψ(1S,2S)→γηc matrix element  accurate hc mass & width inconsistent(>3s) hc mass measurements M1 transition poorly known; Data: y(2s)  p+p-J/y, y(2s), J/y  ghc Exclusive channels  Distorted lineshapes Hard to determine mass and width

  7. First observation of J/ →    CLEO PRL 101, 101801 (2008) Quarkonium analogue of ortho-positronium. Tag J/y with y’→p+p-J/y, • 37 events are inconsistent with gp0/h/h’/hc, • 24.2 events remain after subtracting backgrounds (dominantly g p0 p0). B(J/y → g g g) = (1.2 ± 0.3 ± 0.2) × 10−5 first 3g decay mode of any hadron Agrees with LO QED, but NLO correction takes rate negative! (Higher order corrections very significant.) A search for J/y → g hc; hc → gg leads to an upper limit:B(hc→ g g) < 3×10−4 @ 90% C.L. (PDG: B(hc → gg) = (2.7±0.9)×10−4)

  8. Measure: R1 consistent with known h/h’mixing R2 expected to be equal to R1 but it is not! J/ y, y’→g(p0, h, h’) g h Mode J/y y’ P ψ(’) g g mode dominated by 3 g QED g g 3 p0 CLEO p+ p- p0 g p+p- - PRD(R) 79, 111101 (2009)

  9. Study of ccJ decays χc2 χc0 χc2 χc0 Branching Fractions or 90% CL UL [10-3] CLEO CLEO results for two-baryon final states: PRD 78, 031101(R) (2008) PRD 79, 072007 (2009) Clean and multiple JPC states Especially two body decays: • role of the color octet mechanism • probe gluon content in final states substantial improvement over current world averages in some channels 9

  10. Observation of ccJ(1P) → (, , ) Look for: ’ →(low)cJ cJ→(high) (,,) Significant signals: c1→   c1→   ρ M(π+π−) • The process is expected to be analogous to that of glueball production: J/ψ  γfJ • pQCD, however, predicts rates an order of magnitude below the observations ! • (Gao,Zhang,Chao, Chin.Phys.Lett. 23, 2376 (2006) [arXiv:hep-ph/0607278]) γρ ω M(π+π−π0) γω γφ 1. cut on hadronic mass 2. look at Eγ(low) CLEO PRL 101, 151801 (2008)

  11. Light hadron spectroscopy Glueball spectrum fromLQCD Many results in BESII: ~ 50 publications Much more from BESIII: 100 statistics, 10 g resolution Y. Chen et al., PRD 73 (2006) 014516 Motivation: • Establish spectrum of light hadrons • Search for non-conventional hadrons • Understand how hadrons are formed • Study chiral symmetry in QCD Why at a tau-charm collider ? • Gluon rich • Kinematics favorable • Clean environment, JPC filter

  12. Observation of charged k at BESII •  was first found in K scattering data • However, its phase shift is much less than 180o and it cannot be filled into any nonets of ordinary mesons. There have been hot debates on the existence of . • In recent years: • FNAL E791 found evidence of neutral  in D+ K-++. • CLEO D0 K-+0 data find no evidence of . • FOCUS data on K+K-++ require K*0 interfere with either a constant amplitude or a broad 0+ resonance in K. • BESII observed neutral  in J/  K*0K  KK in 2006. • neutral  pole:

  13. The existence of charged k is expected ! BESII Preliminary K*(1410), K*(1430) M(K0) GeV/c2  • CLEO reported the necessity of in . • However, no charged  is needed in BABAR data. • Charged  is observed at BESII in • Different parameterizations of  are tried in PWA. Consistent results on the pole of charged  are obtained. • The pole position for charged  is consistent with that for neutral  within the error.

  14. This decay mode is thought to be mainly produced from the annihilation of three gluons into ss pair. First observation of (2S)+  M BESII preliminary M Statistical significance ~ 5

  15. QCD studies at low energies ? BESIII: < 2% Phys.Lett.B677,(2009)239 In good agreement with previous results Understand where exactly pQCD becomes invalid Precision measurement of as running Precision measurement of R input to Related toaQED (s), prediction of higgs mass and g-2 A new measurement at BESII on R • Precision at ~ 3.5% • A new determination of s(s): s(M2Z) =

  16. BEPC II Storage ring: Large angle, double-ring RF SR RF Beam energy: 1.0-2 .3GeV Luminosity: 1×1033 cm-2s-1 Optimum energy: 1.89 GeV Energy spread: 5.16 ×10-4 No. of bunches: 93 Bunch length: 1.5 cm Total current: 0.91 A BESIII detector IP

  17. BESIII Commissioning and data taking milestones Mar. 2008: first full cosmic-ray event April 30, 2008: Move the BESIII to IP July 19, 2008: First e+e- collision event in BESIII Nov. 2008: ~ 14M y(2S) events collected April 14, 2009 ~110M y(2S) events collected(4CLEOc) May 30, 2009 42 pb-1 at continuum collected July 28, 2009 ~200M J/y events collected(4 BESII) Peak Lumi. @ Nov. 2008: 1.2 1032cm-2s-1 Peak Lumi. @ May 2009: 3.21032cm-2s-1  • 5 CESRc • 30 BEPC

  18. Achieved Luminosity vs Time Record: 0.32×1033 cm-2s-1 reached in May 14, 2009

  19. BESIII collaboration EUROPE (8) Germany: Univ. of Bochum, Univ. of Giessen, GSI Russia: JINR, Dubna; BINP, Novosibirsk Italy: Univ. of Torino，FrascatiLab Netherland：KVI/Univ. of Groningen US(6) Univ. of Hawaii Univ. of Washington Carnegie Mellon Univ. Univ. of Minnesota Univ. of Rochester Univ. of Indiana Korea (1) SouelNat. Univ. China(26) IHEP, CCAST, Shandong Univ., Univ. of Sci. and Tech. of China Zhejiang Univ., Huangshan Coll. Huazhong Normal Univ., Wuhan Univ. Zhengzhou Univ., Henan Normal Univ. Peking Univ., Tsinghua Univ. , Zhongshan Univ.,Nankai Univ. Shanxi Univ., Sichuan Univ Hunan Univ., Liaoning Univ. Nanjing Univ., Nanjing Normal Univ. Guangxi Normal Univ., Guangxi Univ. Hong Univ., Hong Kong Chinese Univ. Japan (1) Tokyo Univ. Pakistan (1) Univ.of Punjab ~ 300 collaborators 19

  20. Detector performance and calibration ●Layer 7 ●Layer 22 Wire reso. Design: 130 mm dE/dxreso.: 5.80% Design：6-8% CsI(Tl) energy reso. Design: 2.5%@ 1 GeV Barrel TOF reso.: 78ps Design：80-90ps Bhabha

  21. EM transitions: inclusive photon spectrum c1 c2 co c1,2 J/ c BESIII preliminary

  22. Observation of hc: E1-taggedy(2S)p0hc,hcghc background subtracted BESIII preliminary BESIII preliminary N(hc)= 2540±261 c2/d.o.f = 39.5/41.0 Select E1-photon to tag hc A fit of Double-Gaussian signal+ sideband bkg. yield: M(hc)Inc = 3525.16±0.16±0.10 MeV G(hc)Inc = 0.89±0.57±0.23 MeV (First measurement) Br(y’p0hc)×Br(hcghc)Inc =(4.69±0.48(stat)) ×10-4 (G(hc) floated) =(4.69±0.29(stat)) ×10-4 (G(hc) fixed at G(cc1)) Systematic errors under study Details  Dr. LiGang’s talk (see parallel talk)

  23. Observation of hc : Inclusive y(2S)p0hc BESIII preliminary BESIII preliminary Inclusive p0 recoil mass spectrum background subtracted Systematic errors under study Select inclusive p0 A fit of D-Gaussian signal + 4th Poly. bkg yield N(hc) = 9233±935, c2/d.o.f = 38.8/38.0 Combined inclusive and E1-photon-tagged spectrum Br(y’p0hc) = (8.42±1.29(stat)) ×10-4 (First measurement) Br(hcghc) = (55.7±6.3(stat)) % (First measurement) Details  Dr. LiGang’s talk (see parallel talk)

  24. Study of (2S)→ 00 , ( → ,0 → ) (2S)00 Nc0 16645±175 Nc2 4149±82 (2S) Nc0 1541±56 Nc2 291±23 CLEO-c arxiv:0811.0586 Interesting channels for glueball searches Based on 110M y(2S) BK study from 100M inclusive MC sample and 42pb-1 continuum sample Unbinned Maximum Likelihood fit: • Signal: PDF from MC signal • Background: 2nd order Poly.

  25. Confirmation of the BESII observation: pp threshold enhancement in J/y decays  BES III preliminary BES II (2S)→ J/y 0.3 M(pp)-2mp (GeV) +3 +5 -10 -25 M=1859 MeV/c2 G < 30 MeV/c2 (90% CL) M=1865  5 MeV/c2 G < 33 MeV/c2 (90% CL) PRL 91 (2003) 022001

  26. No pp threshold enhancement in y’decays  PRL 99, 011802 (2007) 0.3 Mpp(GeV/c2) No significant narrow strong enhancement near threshold

  27. Study of ccJ → VV, V=w,f • BK from sideband & 100M MC events • Clear cc1 ff signal BESIII preliminary Test QCD-based theory at ccJ decays Puzzles for cc0  VV: no helicity suppress cc1 ff, ww is only allowed for L=2, suppressed ? ccJ fw OZI doubly suppressed

  28. First observation of ccJ wf   0 BESIII preliminary Background from sideband & 100M MC events Clear signal from cc0 /cc1 w(p+p-p0)f(K+K-)

  29. BESIII will resume data taking after summer shutdown, ~5 months until next summer. Possible data taking plans: 500-1000 M J/y events (2-4 months) 500-1000 M y(2s) (2-4 months) 2fb-1y(3770) (4 months) Lineshape scan of y(3770) (2 weeks) Data taking plan in the future: ~10 B J/y events ( 1 year ) ~3 B y(2s) ( 1year ) ~20 fb-1y(3770)+ y(4040)+ y(4160) ( ~5 years) R scan/resonance scan: 2.0-4.6 GeV ( months) Tau physics (months) Possible upgrades: Luminosity: crab waist, bunch spacing, … Beam Energy: Emax = 4.6 GeV  5 GeV e- Polarization Detector: TOF, inner DC, … BESIII Prospects To be decided in Nov.

  30. Prospects: reach charm programs • BESIII (2008 – 2018 ?) • Future charm programs • LHCb at CERN（soon） • BELLE II at SuperB factory（~ 2014 ） • PANDA at GSI（~ 2015） • New machines under discussion: • Frascati(super flavor factory) • Novosibirsk(super tau-charm factory) 2020 ? L ~ 1035-36 cm-2s-1 Expand the life time of tau-charm colliders to > 50 years !

  31. Summary • Great progress by CLEOc charmonium physics • Continuous contributions from BESII • BESIII is operational since 2008: • Detector performance excellent, ready for physics • High quality data samples in hand • Analysis in progress, papers in a few months • In the next few years, there will be great leap on physics of light hadron spectroscopy, charmonium, charm, tau and QCD. • More exciting results is coming

  32. Acknowledgement • All BESIII collaborators • Many CLEOc colleagues • In particular, Yifang Wang, Xiaoyan Shen, Changzheng Yuan, Beijiang Liu, Haibo Li, Gang Li Thank you

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