Charmonium and Exotics

1. Charmonium and Exotics Klaus Peters Ruhr-University Bochum Krakow, June 5, 2004

2. Mesons/Baryons Molecules/Multiquarks Hybrids Glueballs + Effects due to the complicated QCD vacuum Objects of Interest Quark AntiQuark K. Peters - Charmonium and Exotics

3. Light Meson Spectrum qq Mesons Each box corresponds to 4 nonets (2 for L=0) Radial excitations 2–+ 2.5 0–+ Hybrids 2+– 2++ 2–+ 1–– 2.0 exotic nonets 1–+ Glueballs 1+– 1++ 1.5 Lattice 1-+ 1.9 GeV 0+– 0–+ 0++ 1.0 0++ 1.6 GeV L = 0 1 2 3 4 (L = qq angular momentum) K. Peters - Charmonium and Exotics

4. strong interaction C undefined K1A-K1B Kaon mixing strong interaction IG, JPC identical η-η‘ Isoscalar mixing elm interaction ΔI=1 ρ-ω Isospin mixing a1 f1 f1’ K1B JPC=JP+ b1 h1 h1’ K1A JPC=JP- I=1 I=0nn I=0ss I=½ Glueball mixing Hybrid mixing Level Mixing • Light quark problem • the mixing • Mixing • broad states • high level density K. Peters - Charmonium and Exotics

5. Level Mixing • Light quark problem • the mixing • Mixing • broad states • high level density • Better: • narrow states • and/or • lower level density • charmed systems ! K. Peters - Charmonium and Exotics

6. P S Charmed Hybrids • Gluonic excitations of the quark-antiquark-potential may lead to bound states • LQCD: • P-potential of excited gluon fluxin addition to S-potential for one-gluon exchange • mHc ~ 4.2-4.5 GeV/c2 • Light charmed hybridscould be narrow if open charm decays are inaccessible or suppressed important <r2> and rBreakup K. Peters - Charmonium and Exotics

7. q q gMIX gFSI Simplest Hybrids • S-Wave+Gluon (qq)8g with ()8=coloured • 1S0­¯3S1­­ • combined with a 1+ or 1- gluon Meson – Hybrid Mixing Exotic JPCcannot! be formedby qq K. Peters - Charmonium and Exotics

8. LQCD ccg 1-+ vs. cc 1-- (J/y) K. Peters - Charmonium and Exotics

9. 1-- (0,1,2)-+ < 1++ (0,1,2)+- JKM00, NPB83Suppl83(2000)304 and Manke, PRD57(1998)3829 L-Splitting Dm ~ 100-250 MeV/c2 for 1-+ to 0+- S-Splittings Page thesis,1995 and PRD35(1987)1668 4.14 (0-+ ) to 4.52 GeV/c2 (2-+) consistent w/LQCD JKM, NPB86suppl(2000)397, PLB478(2000) 151 2+- 4.85 1++ 4.81 1+- 4.70 2-+ 4.52 1-- 4.48 0+- 4.47 1-+ 4.37 4.3 4.5 4.1 4.4 4.7 4.6 4.8 4.2 0-+ 4.14 Charmed Hybrid Level Scheme DD** K. Peters - Charmonium and Exotics

10. Meson Hybrid Fluxtube ~ Simplified Lattice Approach Flux (excited Gluon) carries angular momentum Bali, priv. comm., 1991 K. Peters - Charmonium and Exotics

11. Proposed Decays K. Peters - Charmonium and Exotics

12. 8.0 4.0 7.1 3.9 3.8 6.3 3.7 3.6 5.5 3.5 3.4 3.3 4.8 3.2 3.1 4.1 3.0 3.4 2.9 JP=0- 1- 1+ (0,1,2)+ 2- (1,2,3)- Charmonium Physics Open questions … ψ(33S1) D*D* χc2(23P2) ψ(13D3) pp [GeV/c] Mcc [GeV/c2] ηc(31S0) χc1(23P1) Peculiar ψ(4040) ψ(13D2) DD* h1c(21P1) χc0(23P0) ψ(11D2) ψ(13D1) DD Terra incognita for 2P and 1D-States ψ(23S1) ηc(21S0) χc2(13P2) h1c(11P1) χc1(13P1) ηc’- ψ(2S) splitting χc0(13P0) h1c– unconfirmed … Exclusive Channels Helicity violation G-Parity violation Higher Fock state contributions J/ψ(13S1) ηc – inconsistencies ηc(11S0) K. Peters - Charmonium and Exotics

13. The c(11S0) T. Skwarnicki – Lepton Photon 2003 M(c) = 2979.9  1.0 MeV (c) = 25.5  3.3 MeV K. Peters - Charmonium and Exotics

14. The Belle collaboration has recently presented a 6 signal for BKKSK which they interpret as evidence for c production and decay via the process: with: in disagreement with the Crystal Ball result, but reasonably consistent with potential model expectations. (DPF 2002). The c(21S0) discovery by BELLE K. Peters - Charmonium and Exotics

15.   c(21S0) T. Skwarnicki – Lepton Photon 2003 Log-scale BaBar 88 fb-1 Preliminary M(c) = 3637.7  4.4 MeV (c) = 19  10 MeV K. Peters - Charmonium and Exotics

16. Quantum numbers JPC=1+- The mass is predicted to be within a few MeV of the center of gravity of the c(3P0,1,2) states Mcog=1/9 {M(cc0)+3M(cc1)+5M(cc2)} The width is expected to be small (hc)  1 MeV The dominant decay mode c ( 50 %) It can also decay to J/: J/0 violates isospin J/+- suppressed by phase space and angular momentum barrier Analysis of E835 data (also in other channels) underway Expected properties of the h1c(1P1) pp®h1c®J/yp0 E760 M(h1c) = 3526.2  0.15  0.2 MeV (h1c) < 1.1 MeV K. Peters - Charmonium and Exotics

17. The hc(1P1) 1P1 vs 3Pcog mass – distinguish models • In QM triplet-singlet splittings test • the Lorentz nature of the confining potential • Relativistic effects • important validation of • lattice QCD calculations • NRQCD calculations • Observation and precision measurementof 1P1 states is an important test of theory S. Godfrey – QWG03 K. Peters - Charmonium and Exotics

18. The X(3872) New state discovered by Belle in BK (J/+-), J/µ+µ- or e+e- X(3872) seen also by CDF M = 3872.0  0.6  0.5 MeV  2.3 MeV (90 % C.L.) M = 3871.4  0.7  0.4 MeV K. Peters - Charmonium and Exotics

19. DD Possible interpretations • y(13D2) • D-states have negative parity, spin-2 states cannot decay to DD • They are narrow as long as below the DD* threshold • y(11D2) • preferentially decays to h1c • decays to p+p-J/y would be of magnetic type and suppressed • Width • Some models predict large widths for y(13D2) → p+p-J/y • All models predict even larger widths for y(13D2) → gcc2 • D0D*0 Molecule ? • No model can accomodate (3770) and X(3872) in the same 13DJ triplet. • Can coupled channel effects and (13D1)- (23S1) mixing change this ? y(13D3) y(11D2) y(13D2) y(13D1) 14% g g g 65% g g 7% 20% 32% p+p- g Based on: E.J.Eichten, K.Lane C.Quigg PRL 89,162002(2002) J/y K. Peters - Charmonium and Exotics

20. Charmonium States above the DD threshold • It is extremely important • to identify as many missing states above the open charm threshold as possible • and to confirm the ones for which we only have a weak evidence. • This will require • high-statistics • small-step scans of the • entire energy region accessible at GSI. K. Peters - Charmonium and Exotics

21. CBall E835 100 cc1 1000 CBall ev./2 MeV E 835 ev./pb ECM 3500 3510 3520 MeV Charmonium Physics • e+e- interactions: • Only 1-- states are formed • Other states only bysecondary decays (moderate mass resolution) • pp reactions: • All states directly formed(very good mass resolution) K. Peters - Charmonium and Exotics

22. Exotics in Proton-Antiproton • Exotics are heavily produced in pp reactions • High production yields for exotic mesons (or with a large fraction of it) • f0(1500)p® ~25 % in 3p0 • f0(1500)p® ~25 % in 2hp0 • p1(1400)p® >10 % in p±p0h Crystal Barrel Interference with other well known (conventional) states is mandatory for the phase analysis K. Peters - Charmonium and Exotics

23. p p p p G G p p H H H H _ _ _ _ _ _ p p p p M p p M M Proton-Antiproton @ Rest/Flight nng ssg/ccg • Gluon rich process creates gluonic excitation in a direct way • cc requires the quarks to annihilate (no rearrangement) • yield comparable to charmonium production • even at low momenta large exotic content has been proven • Momentum range for a survey pp® ~15 GeV • But also Glueball Formation Production all JPC available Formation only selected JPC K. Peters - Charmonium and Exotics

24. Summary and Outlook • It’s an amazing time in charm spectroscopy • many new states – but a lot is missing for a coherent picture • What are the new DsJ states • what are their properties like width and decay channels • How do the new cc findings fit into one model • like the new X(3872) state • understand the large width of the cc groundstate hC • and the hC-y(2S) splitting • Where are gluonic excited charmonia (hybrids) • spectrum, widths and decay channels • Only high precision experiments can finallyhelp to solve the puzzle like Panda @ HESR @ GSI K. Peters - Charmonium and Exotics

25. Accessible cc-Hadrons at PANDA • Other exotics with identical decay channels ® same region mass and phase space of recoil meson for exotic JPC included conventional charmonium K. Peters - Charmonium and Exotics