QCD Exotics and Charmonium Klaus Peters Ruhr-University Bochum 2nd Workshop "Challenges and Opportunities at the New International Accelerator Facility for Beams of Ions and Antiprotons at Darmstadt GSI, Oct 15, 2003

2 K. Peters - QCD Exotics and Charmonium Related Talks Oct 15: 16:30Hadron PhysicsMadeleine Soyeur, CEA, Saclay Oct 16: 10:20Phenomenology of Hadron Spectroscopy Ted Barnes, ORNL, Oak Ridge 11:20Hadrons and Gluonic Excitations on the Lattice Chris Michael, Liverpool Oct 17: 16:35Hadron PhysicsSerge Kox, Grenoble

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

4 K. Peters - QCD Exotics and Charmonium Objects of Interest SU(3) C Symmetry tells us that q 3i+n q 3j+n g k is color neutral i=1 j,n,k=0 baryon (B=i-j) i,j,k=0 n=1 meson i,j,n=0 k>1 glueball i,j=0 n=1 k>0 meson hybrid i=1 j,n=0 k>0 baryon hybrid i,n=1 j,k=0penta quark i,j,k=0 n=2four quark i,j,k=0 n=3 / i,j=3 k,n=0baryonium (hexa quark)

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

6 K. Peters - QCD Exotics and Charmonium Level Mixing Mixing (Light Quark) broad states high level density Better: narrow states and/or lower level density charmed systems !

7 K. Peters - QCD Exotics and Charmonium Charmed Hybrids Gluonic excitations of the quark-antiquark-potential may lead to bound states LQCD: -potential of excited gluon flux in addition to -potential for one-gluon exchange m Hc ~ GeV/c 2 Light charmed hybrids could be narrow if open charm decays are inaccessible or suppressed   important and r Breakup

8 K. Peters - QCD Exotics and Charmonium Simplest Hybrids S-Wave+Gluon (qq) 8 g with () 8 =coloured 1 S 0  3 S 1  combined with a 1 + or 1 - gluon Gluon1 – (TM) 1 +(TE) 1 S 0, 0 – –– 3 S 1, 1 –– – – –+ Meson – Hybrid Mixing g MIX g FSI q q Exotic J PC cannot! be formed by qq

9 K. Peters - QCD Exotics and Charmonium LQCD ccg 1 -+ vs. cc 1 -- (J/) 1 -+ m(ccg)ModelGroupReference 4390±80±200 isotropicMILC97PRD56(1997) ±150 isotropicMILC99NPB93Supp(1999) isotropicJKM99PRL82(1999) ±37±99 anisotropicZSU02hep-lat (1 -+,1 -- ) m(ccg)- m(cc) 1340±80±200 isotropicMILC97PRD56(1997) ±150 isotropicMILC99NPB93Supp(1999) ±130 anisotropicCP-PACS99PRL82(1999) isotropicJKM99PRL82(1999) ±37±99 anisotropicZSU02hep-lat

10 K. Peters - QCD Exotics and Charmonium Charmed Hybrid Level Scheme 1 -- (0,1,2) -+ < 1 ++ (0,1,2) +- JKM00, NPB83Suppl83(2000)304 and Manke, PRD57(1998)3829 L-Splitting m ~ MeV/c 2 for 1 -+ to 0 +- S-Splittings Page thesis,1995 and PRD35(1987) (0 -+ ) to 4.52 GeV/c 2 (2 -+ ) consistent w/LQCD JKM, NPB86suppl(2000)397, PLB478(2000) DD**

11 K. Peters - QCD Exotics and Charmonium Charmed Hybrid Level Scheme 1 -- (0,1,2) -+ < 1 ++ (0,1,2) +- JKM00, NPB83Suppl83(2000)304 and Manke, PRD57(1998)3829 L-Splitting m ~ MeV/c 2 for 1 -+ to 0 +- S-Splittings Page thesis,1995 and PRD35(1987) (0 -+ ) to 4.52 GeV/c 2 (2 -+ ) consistent w/LQCD JKM, NPB86suppl(2000)397, PLB478(2000) DD**

12 K. Peters - QCD Exotics and Charmonium Charmonium Physics Open questions …  c – inconsistencies  c’ -  (2S) splitting h 1c ( 1 P 1 ) unconfirmed Peculiar decays of (4040) Terra incognita for any 2P and D-States … Exclusive Channels Helicity violation G-Parity violation Higher Fock state contributions

13 K. Peters - QCD Exotics and Charmonium The  c (1 1 S 0 ) M(  c ) =  1.0 MeV  (  c ) = 25.5  3.3 MeV T. Skwarnicki – Lepton Photon 2003

14 K. Peters - QCD Exotics and Charmonium The  c (1 1 S 0 ) Despite the recent measurements by E835 not much is known about the ground state of charmonium: the error on the mass is still bigger than 1 MeV/c 2 recent measurements give larger widths than previously expected A large value of the  c width is difficult to explain in terms of simple quark models Also unusually large branching ratios into channels involving multiple kaons and pions have been reported. A precision measurements of the  c mass, width and branching ratios is of the utmost importance, and it can can only be done in by direct formation in pp.

15 K. Peters - QCD Exotics and Charmonium The  c (2 1 S 0 ) discovery by BELLE The Belle collaboration has recently presented a 6 signal for BKK S K 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).

16 K. Peters - QCD Exotics and Charmonium    c (2 1 S 0 ) BaBar 88 fb -1 Preliminary Log-scale M(  c ) =  4.4 MeV  (  c ) = 19  10 MeV T. Skwarnicki – Lepton Photon 2003

17 K. Peters - QCD Exotics and Charmonium Quantum numbers J PC =1 +- The mass is predicted to be within a few MeV of the center of gravity of the  c ( 3 P 0,1,2 ) states M cog =1/9 { M(  c0 )+3M(  c1 )+5M(  c2 ) } The width is expected to be small  (h c )  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 Expected properties of the h 1c ( 1 P 1 ) M(h 1c ) =  0.15  0.2 MeV ( h 1c ) < 1.1 MeV E760 Analysis of E835 data (also in other channels) underway pph 1c J/  0

18 K. Peters - QCD Exotics and Charmonium S. Godfrey – QWG03 The h c ( 1 P 1 ) 1 P 1 vs 3 P cog 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 measurement of 1 P 1 states is an important test of theory

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

20 K. Peters - QCD Exotics and Charmonium  (1 1 D 2 )  (1 3 D 2 )  (1 3 D 3 )  (1 3 D 1 ) DD  J       7% 65% 14% 32%20% Based on: E.J.Eichten, K.Lane C.Quigg PRL 89,162002(2002) Possible interpretations (1 3 D 2 ) D-states have negative parity, spin-2 states cannot decay to DD They are narrow as long as below the DD* threshold (1 1 D 2 ) preferentially decays to h 1c decays to  +  - J/ would be of magnetic type and suppressed Width Some models predict large widths for (1 3 D 2 ) →  +  - J/ All models predict even larger widths for (1 3 D 2 ) →   c2 D 0 D *0 Molecule ? No model can accomodate (3770) and X(3872) in the same 1 3 D J triplet. Can coupled channel effects and (1 3 D 1 )- (2 3 S 1 ) mixing change this ?

21 K. Peters - QCD Exotics and Charmonium 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. Charmonium States above the DD threshold

22 K. Peters - QCD Exotics and Charmonium MeV3510 CBall ev./2 MeV 100 E CM Charmonium Physics e + e - interactions: Only 1 -- states are formed Other states only by secondary decays (moderate mass resolution) pp reactions: All states directly formed (very good mass resolution) CBall E E 835 ev./pb  c1

23 K. Peters - QCD Exotics and Charmonium E CM Resonance Scan Measured Rate Beam Profile Resonance Cross Section small and well controlled beam momentum spread p/p is extremely important

24 K. Peters - QCD Exotics and Charmonium Charmonium Physics with pp Expect 1-2 fb -1 (like CLEO-C) pp (>5.5 GeV/c) J/10 7 /d pp (>5.5 GeV/c)  c2 (J/10 5 /d pp (>5.5 GeV/c)  c ‘(10 4 /d| rec. ? Comparison of to E835 Maximum energy 15 GeV/c instead of 9 GeV/c Luminosity 10x higher Detector with magnetic field – charged final states p/p 10x better Dedicated machine with stable conditions

25 K. Peters - QCD Exotics and Charmonium Exotics in Proton-Antiproton Exotics are heavily produced in pp reactions High production yields for exotic mesons (or with a large fraction of it) f 0 (1500)  ~25 % in 3  f 0 (1500)  ~25 % in 2   1 (1400)  >10 % in      Crystal Barrel Interference with other well known (conventional) states is mandatory for the phase analysis

26 K. Peters - QCD Exotics and Charmonium Rest/Flight 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 p p ~15 GeV But also Glueball Formation p p _ G M p M H p _ p M H p _ p p _ G p p _ H p p _ H Production all J PC available Formation only selected J PC nngnngssg/ccg

27 K. Peters - QCD Exotics and Charmonium Heavy Glueballs Light gg/ggg-systems are complicated to identify (mixing!) Exotic heavy glueballs m(0 +- ) = 4140 (50)(200) MeV m(2 +- ) = 4740 (70)(230) MeV Width unknown, but! nature invests more likely in mass than in momentum newest proof: double cc yield in e + e - Flavour-blindness predicts decays into charmed final states too Same run period as hybrids In addition: scan m>2 GeV/c 2 Morningstar und Peardon, PRD60 (1999) Morningstar und Peardon, PRD56 (1997) 4043

28 K. Peters - QCD Exotics and Charmonium Open charm discoveries The D S ± Spectrum |cs> +c.c. was not expected to reveal any surprises Potential model Old measurements New observations 00 11 00 11 22 33 DsDs Ds*Ds* D sJ * (2317) D s1 m [GeV/c 2 ] D0KD0K D*K D sJ (2458) D s2 JPJP

29 K. Peters - QCD Exotics and Charmonium # 1267  53 Events in peak # 273  33 Events in peak M =  0.4 MeV  = 8.6  0.5 MeV Resolution from MC is  = 8.9  0.2 MeV M =  1.3 MeV  = 8.8  1.1 MeV D sJ *(2317) +  D s +  0 D s +  K + K –  +  0 D sJ *(2317) +  D s +  0 D s +  K + K –  + Combinatorial D S *+  D S *+ (2112) BABARBABAR BABARBABAR New State in Two D s + Modes

30 K. Peters - QCD Exotics and Charmonium m = ± 1.2 MeV/c 2 m = ± 1.4 MeV/c 2 D s * Sideband m(K + K -  +  0  )- m(K + K -  +  ) [GeV/c 2 ] m(K + K -  +  0  )- m(K + K -  +  ) BABARBABAR BABARBABAR DifferenceSignal + Sideband Search for a D s +  0  State N = 140 ± 22

31 K. Peters - QCD Exotics and Charmonium BF(D sJ (2458)D s  ) BF(D sJ (2458)D s *   ) 0.63  0.15  0.15 (continuum) 0.38  0.11  0.04 (B decays) = = 0.47  0.10 Consistent with 1 + hypothesis, 0 +, 2 + are excluded Continuum B decays D sJ (2458)D s  decay Belle

32 K. Peters - QCD Exotics and Charmonium Explanation: Chiral doubling? Ground states D S ± (J P =0  ) D S *± (J P =1  ) m=144 MeV/c 2 have chiral partners D sJ * (2317) (J P =? + ) D sJ (2458) (J P =1 + ) m=141 MeV/c 2 Prediction D s1 (2536) (J P =1 + ) and D sJ (2573) (if J P =2 + ) m=37 MeV/c 2 have also chiral partners at 2721±10 MeV/c 2 (J P =1  ) and 2758±10 MeV/c 2 (J P =2  ) m=37 MeV/c 2 Nowak, Rho, Zahed

33 K. Peters - QCD Exotics and Charmonium 4-Quark States, DK Molecules C=+1, S=+1 |D 0 K + > ≈ |cuus>  |csuu>  |D S + π 0 > + |D S + η> |D + K 0 > ≈ |cdds>  |csdd>  –|D S + π 0 > + |D S + η> |D S + π 0 > decay of |D 0 K + > – |D + K 0 >(I=1) |D S + η> decay of |D 0 K + > + |D + K 0 >(I=0) |D 0 K 0 > ≈ |cuds>  |csdu>  |D S + π - > |D + K + > ≈ |cdus>  |csud>  |D S + π + > C=+1, S=-1 |D 0 K - > ≈ |cuus>  |udsuus>  |π + K - K - > |D + K - > ≈ |cdus>  |udsdus> |π + K 0 K - >  |π + K S K - > |D + K 0 > ≈ |cdds>  |udsdds> |π + K 0 K 0 >  |π + K S K S > cW + s  ud s Lipkin, Close, Barnes and others

34 K. Peters - QCD Exotics and Charmonium D s[J] [*]± Pairproduction in pp Annihilation Associated Pair m/MeV/c 2 JPJP Channel (+cc)Final State D s (1968.5) ,1 -,2 +,3 -,4 + Ds+Ds-Ds+Ds- 2K - 2K +  +  - D s (1968.5)D s * (2112.4) ,1 -,1 +,2 -,2 +,3 -,3 +,4 -,4 + D s + (D s - )2K - 2K +  +  -  D s * (2112.4) ,0 +,1-,1 +,2 -,2 +,3 -,3 +,4 -,4 + (D s + )(D s - )2K - 2K +  +  -  D s (1968.5)D sJ * (2317.5) ,1 +,2 -,3 +,4 - D s + (D s -  0 )2K - 2K +  +  -  0 D s (1968.5)D sJ (2458.5) ,1 -,1 +,2 -,2 +,3 -,3 +,4 -,4 + D s + ((D s - ) 0 )2K - 2K +  +  -  0  D s * (2112.4)D sJ * (2317.5) ,1 -,1 +,2 -,2 +,3 -,3 +,4 -,4 + (D s + )(D s -  0 )2K - 2K +  +  -  0  D s (1968.5)D s1 (2535.4) ,1 -,1 +,2 -,2 +,3 -,3 +,4 -,4 + D s + (D *- K 0 ) 2K - K + K S  + 2 - ( 0 ) D s (1968.5)D sJ * (2572.4) ,1 -,1 +,2 -,2 +,3 -,3 +,4 -,4 + D s + (D 0 K - ) 2K - 2K +  +  - ( 0 ) D s * (2112.4)D sJ (2458.5) ,0 +,1-,1 +,2 -,2 +,3 -,3 +,4 -,4 + (D s + )((D s - ) 0 )2K - 2K +  +  -  0  D sJ * (2317.5) ,1 -,2 +,3 -,4 + (D s +  0 )(D s -  0 )2K - 2K +  +  - 2 0 D s * (2112.4)D s1 (2535.4) ,0 +,1-,1 +,2 -,2 +,3 -,3 +,4 -,4 + (D s + )(D *- K 0 )2K - K + K S  + 2 - ( 0 ) D s * (2112.4)D sJ * (2572.4) ,0 +,1-,1 +,2 -,2 +,3 -,3 +,4 -,4 + (D s + )(D 0 K - )2K - 2K +  +  - ( 0 ) D s (1968.5)D 1 * (2770) ,1 -,1 +,2 -,2 +,3 -,3 +,4 -,4 + D s + (D s -  +  - )2K - 2K + 2 + 2 - D sJ * (2317.5)D sJ (2458.5) ,1 -,1 +,2 -,2 +,3 -,3 +,4 -,4 + (D s +  0 )((D s - ) 0 )2K - 2K +  +  - 2 0  D s (1968.5)D 2 (2870) ,1 -,1 +,2 -,2 +,3 -,3 +,4 -,4 + D s + ((D s - ) +  - )2K - 2K + 2 + 2 -  D sJ * (2317.5)D s1 (2535.4) ,1 -,1 +,2 -,2 +,3 -,3 +,4 -,4 + (D s +  0 )(D *- K 0 )2K - K + K S  + 2 - (1-2) 0 D s * (2112.4)D 1 * (2770) ,0 +,1-,1 +,2 -,2 +,3 -,3 +,4 -,4 + (D s + )(D s -  +  - )2K - 2K + 2 + 2 -  D sJ * (2317.5)D sJ * (2572.4) ,1 -,1 +,2 -,2 +,3 -,3 +,4 -,4 + (D s +  0 )(D 0 K - )2K - 2K +  +  - (1-2) 0 D sJ (2458.5) ,0 +,1-,1 +,2 -,2 +,3 -,3 +,4 -,4 + ((D s + ) 0 )((D s - ) 0 )2K - 2K +  +  - 2 0  D s * (2112.4)D 2 (2870) ,0 +,1-,1 +,2 -,2 +,3 -,3 +,4 -,4 + (D s + )((D s - ) +  - )2K - 2K + 2 + 2 -  D sJ (2458.5)D s1 (2535.4) ,0 +,1-,1 +,2 -,2 +,3 -,3 +,4 -,4 + ((D s + ) 0 )(D *- K 0 )2K - K + K S  + 2 - (1-2) 0  D sJ (2458.5)D sJ * (2572.4) ,0 +,1-,1 +,2 -,2 +,3 -,3 +,4 -,4 + ((D s + ) 0 )(D 0 K - )2K - 2K +  +  - (1-2) 0  D s1 (2535.4) ,0 +,1-,1 +,2 -,2 +,3 -,3 +,4 -,4 + (D *+ K 0 )(D *- K 0 )K - K + 2K S 2 + 2 - (0-2) 0

35 K. Peters - QCD Exotics and Charmonium Why Antiprotons ? high resolution spectroscopy with p-beams in formation experiments: E  E beam high yields in pp of gluonic excitations glueballs, charmed hybrids event tagging by pair wise associated production, (particle, anti-particle) e.g. pp  bar large √s at low momentum transfer important for in-medium "implantation" of hadrons: study of in-medium effects of charmed states

36 K. Peters - QCD Exotics and Charmonium 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 D sJ 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  C and the  C -  (2S) splitting Where are gluonic excited charmonia (hybrids) spectrum, widths and decay channels Only high precision experiments can finally help to solve the puzzle like GSI

37 K. Peters - QCD Exotics and Charmonium Accessible cc-Hadrons at GSI Other exotics with identical decay channels  same region mass and phase space of recoil meson for exotic J PC included conventional charmonium