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Introduction and Status of QCD Exotics K. Peters GSI Darmstadt/JWGU Frankfurt Hadron Physics at COSY 2005 Bad Honnef, July 25-29.

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Presentation on theme: "Introduction and Status of QCD Exotics K. Peters GSI Darmstadt/JWGU Frankfurt Hadron Physics at COSY 2005 Bad Honnef, July 25-29."— Presentation transcript:

1 Introduction and Status of QCD Exotics K. Peters GSI Darmstadt/JWGU Frankfurt Hadron Physics at COSY 2005 Bad Honnef, July 25-29

2 2 K. Peters - Status of QCD Exotics Overview Introduction Status of Spin-Exotics Status of Glueball-Search Future Experiments Not covered Pentaquarks Baryonium Charmonium-Spectrum

3 3 K. Peters - Status of QCD Exotics What are EXOTIC hadrons ? Unconventional hadrons Depends on what is the convention Convention Matter is build out of quarks proton consists of 3 quarks pion consists of a quark and an antiquark Unconventional Hadronic matter is not made entirely out of quarks Quark configurations different from baryons and mesons But not forbidden !

4 4 K. Peters - Status of QCD Exotics Classification (Close & Lipkin) Exotics of the first kind External quantum numbers unambiguously incompatible with assignment to baryons or mesons B=1 – baryon-like Q>2, Q 0, I>3/2,.... B=0 – meson-like |Q|>1, I>1, |S|>2, |C|>2, |S-C|>1,.... 1

5 5 K. Peters - Status of QCD Exotics Classification (Close & Lipkin) Exotics of the second kind Combination of quantum numbers not allowed for leading Fock-term Only possible for B=0 J PC = 0 --, 0 +-,1 -+, 2 +-,... cannot be formed by any unexcited qq-System 2

6 6 K. Peters - Status of QCD Exotics Classification (Close & Lipkin) Exotics of the third kind – Crypto-Exotics Internal exotic structure like gluonic excitations like N-quarks but no model free signature approach: overpopulation of hadron multiplets unexpected masses and decay properties a well understood conventional meson picture is mandatory 3

7 7 K. Peters - Status of QCD Exotics Meson Spectrum after the LEAR Era The LEAR Era with the CERN Asterix/Obelix Crystal Barrel Jetset/PS185 BNL FNAL VES/Gams produced impressive results with high statistics and high resolution

8 8 K. Peters - Status of QCD Exotics SPIN-PARITY EXOTICS (2 nd Kind) Search for Hybrids

9 9 K. Peters - Status of QCD Exotics Intermediate State Mixing Many states may contribute to a final state not only ones with well defined (already measured) properties not only expected ones Many mixing parameters are poorly known K-phases SU(3) phases In addition also D/S mixing (b 1,a 1 decays)

10 10 K. Peters - Status of QCD Exotics 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

11 11 K. Peters - Status of QCD Exotics Fluxtube Predictions N. Isgur, R. Kokoski und J. Paton, Phys. Rev. Lett. 54 (1985) 869 and refs therein F.E. Close und P. R. Page, Nucl. Phys. B443 (1995) 233 (u,d)g (n,s)g ccgccg

12 12 K. Peters - Status of QCD Exotics Light-quark hybrids recent new determination of exotic 1 -+ hybrid meson improved staggered fermions (lighter quark masses) quenched and unquenched, Wilson gluon action a ~ 0.09 fm lightest mass still above experiment MILC, hep-lat/ quenched continuum limit (around strange quark mass)

13 13 K. Peters - Status of QCD Exotics Rediscovery of the  1 (1400) πp  π - η p (and  π 0 η n) pd   π - π 0 η Rest in liq.D2

14 14 K. Peters - Status of QCD Exotics Proof of evidence for exotic wave - CB

15 15 K. Peters - Status of QCD Exotics Controversary in E852 FSI Description in ηπ - Szczepaniak, et al., PRL 91, (2003)

16 16 K. Peters - Status of QCD Exotics Controversary in E852, cont‘d in E852 in ηπ 0 the amplitudes are different for different regions BW solution fails

17 17 K. Peters - Status of QCD Exotics π 1 (1400) Summary 1400 MeV/c 2 region well established phase motion against a 2 (1320) in π  p interference with ρ(770) in rest signal in πη is at b 1 π and f 1 π threshold influences results line shapes and pole positions affected exotic wave is evident it might span over a wide range is it a Hybrid? probably not – decuplet state?

18 18 K. Peters - Status of QCD Exotics E852 ρπ π - p  π - ρ 0 p  π - π - π + p shows a clear resonance in the 1 -+ wave around 1600 MeV/c 2

19 19 K. Peters - Status of QCD Exotics VES η‘π resonant structure in η‘π at 1600 MeV/c 2 in ηπ at 1400 MeV/c 2 η and η‘ are coupled via SU(3) any interpretation of the π 1 resonances have to explain the difference Verification of πη(') results in ρπ channel ρ(16xx) observed by two independent experiments in ρπand η‘π E852

20 20 K. Peters - Status of QCD Exotics E852 f 1 π and b 1 π blue one 1 -+ pole black two poles  2 =70.6/47=1.5 E852

21 21 K. Peters - Status of QCD Exotics E852 more b 1 π first observation of a non 1 -+ exotic h 2 (1950) with JPC=2 +- M=1954±8 Γ=138±3 another h 2 may be at M=2300

22 22 K. Peters - Status of QCD Exotics Spin-exotic Summary thanks to G. Adams, RPI

23 23 K. Peters - Status of QCD Exotics   Charmed Hybrids LQCD: gluonic excitations of the quark-antiquark-potential may lead to bound states -potential for one-gluon exchange -potential from excited gluon flux m Hcc ~ GeV/c 2 Light charmed hybrids could be narrow if open charm decays are inaccessible or suppressed   important and r Breakup R/r 0 V( R )/GeV J/ψ χcχc ψ‘ψ‘ HccHcc D

24 24 K. Peters - Status of QCD Exotics GLUEBALLS (usually 3 rd Kind)

25 25 K. Peters - Status of QCD Exotics SU(N) Glueballs on the Lattice recent study of 0 ++,2 ++, 0 ++ * glueballs in SU(N), N=2,3,4,5 masses depend linearly on N large N limits differ little from N=3 Lucini, Teper, JHEP 06, 050 (2001). Morningstar und Peardon, PRD60 (1999) Morningstar und Peardon, PRD56 (1997) 4043

26 26 K. Peters - Status of QCD Exotics f 0 (1500) – Crystal LEAR f 0 (1500) is very narrow (~100 MeV/c 2 ) and decays dominantly to (2n)π

27 27 K. Peters - Status of QCD Exotics f j (1710) in radiative J/ decays Mark III and DM2 found a scalar 1700 MeV/c 2 in KK in radiative decays of the J/ It took more than a decade to establish the scalar nature of this object DM2 MarkIII

28 28 K. Peters - Status of QCD Exotics SOZI - DOZI - Analysis f 0 (1500) in 4π and f j (1710) in KK “DOZI”-enhanced both should contain remarkable gg content

29 29 K. Peters - Status of QCD Exotics Central Production CERN-experiments: WA76, WA91, WA102 Important results in the scalar (ππ,KK,K s K s,4) tensor (ππ,KK,K s K s,4) pseudoscalar (KKπ,ππη) sectors But:  ~ 1/M 2 no charm-sector partial wave (moment)- analysis complicated little фф,ωω statistics Future: Compass, much higher statistics

30 30 K. Peters - Status of QCD Exotics Meson Glueball Mixing Physical Masses f 0 (1370),f 0 (1500),f 0 (1710) Bare Masses: m 1,m 2,m G (G) (S) (N) f 0 (1370)-0.69  0.07 f 0 (1500)-0.65 0.04–0.700.07 f 0 (1710)0.39  0.02 m 1 =137720 m 2 =167410 m G =144324 octet piece Lattice of about 1600

31 31 K. Peters - Status of QCD Exotics Anisovich & Sarantsev Anisovich and Sarantsev, hep-ph/ K-Matrix approach M= 280 – 1900 MeV Uses data from GAMS at small and large nucleon momentum E852 CERN-Munich scattering Crystal Barrel For the channels ππ, ηη, ηη‘, KK, ππππ No f 0 (600) = σ Found f 0 (980), f 0 (1300), f 0 (1500), f 0 (1750) and f 0 ( )

32 32 K. Peters - Status of QCD Exotics D S +  π + π - π + (+c.c) E791 BaBar E.M. Aitala et al., PRL 765 (2001) B. Lewandowski, Proc. Meson 2002 PHD Th. Deppermann, Bochum E E. PRELIMINARY D DSDS non-unitary approach needs interference of 4 resonances for the strange peak  K-Matrix approach resolves it

33 33 K. Peters - Status of QCD Exotics D +  π + π - π + (+c.c) E791 E.M. Aitala et al., PRD 770 (2002) 1172 E. non-unitary approach yields 50% σ  K-Matrix approach removes any σ contribution

34 34 K. Peters - Status of QCD Exotics Problems in Analysis and Interpretation many processes, therefore no trivial production amplitude coupled channels contain very many production amplitudes complicated interferences in K 0 S K 0 S contr. from K 0 K 0 and K 0 K 0 directFSI directFSI directFSI ++ W c s _ s s _ W c s _ s _ s I=0, KK* or c.c. _ noonly K 0 K 0 *+c.c. W c s _ s _ s _ DCS W c s _ s _ s ColorS

35 35 K. Peters - Status of QCD Exotics The scalar particles most interpretations assume the doubtless K 0 *(1430) from LASS to be the I=1/2-state and that the a 0 (1400) is the I=1-state two classes of arrangements 0 a 0 (980) & f 0 (975) are isospin-partner a 0 (980) & f 0 (975) are completely independent a reasonable model must be able to handle the mixing of isoscalars as well as t- and u-channel exchange

36 36 K. Peters - Status of QCD Exotics Scalar Summary Puzzle still unsolved....

37 37 K. Peters - Status of QCD Exotics 2 GeV Tensors Sorted by measured final state Structure unclear

38 38 K. Peters - Status of QCD Exotics f 2 (1920)

39 39 K. Peters - Status of QCD Exotics f 2 (2200) Broad resonance at 2.2 GeV/c 2

40 40 K. Peters - Status of QCD Exotics SUMMARY and OUTLOOK I Hybrids Many Spin-Parity Exotics π 1 (1400) *** π 1 (1600) **** π 1 (2000) ** h 2 (1950) * h 2 (2300) (*) Future investigations GlueX for the light quark sector Panda for the onia and heavy light sector

41 41 K. Peters - Status of QCD Exotics SUMMARY and OUTLOOK II Glueballs Too many scalars with an unclear nature experimental situation fairly good, saturated D (s) -decays can not help solving this issue Many unconfirmed tensors important field for the future to settle the spectrum BESIII and Panda are well suited

42 42 K. Peters - Status of QCD Exotics FUTURE EXPERIMENTS

43 43 K. Peters - Status of QCD Exotics pion π - p  X 0 n exotic/non-exotic ~ 1 exotic/non-exotic ~ 0.1 Szczepaniak & Swat (01) photon γp  X + n Possible narrow QCD exotic (M=1.6 GeV) (E852 π - p  π + π - π - p) Implications for exotic meson searches

44 44 K. Peters - Status of QCD ExoticsCHL-2 Upgrade magnets and power supplies Hall JLab and the 12 GeV Upgrade Construction start - 200? Physics - 200?+4

45 45 K. Peters - Status of QCD Exotics The GSI Future Facility Panda Existing GSI Facilities

46 46 K. Peters - Status of QCD Exotics p Momentum [GeV/c] Mass [GeV/c 2 ] Two body thresholds Molecules Gluonic Excitations qq Mesons Hybrids Hybrids+Recoil Glueball Glueball+Recoil ΛΛ ΣΣ ΞΞ ΛcΛcΣcΣcΞcΞcΛcΛcΣcΣcΞcΞc ΩcΩcΩcΩc ΩΩD DsDsDsDs qqccqqccqq nng,ssgccgccg ggg,gg light qq π,ρ,ω,f 2,K,K *c J/ψ, η c, χ cJ nng,ssgccgccg ggg Accessible Charmed Hadrons at GSI Other exotics with identical decay channels  same region conventional charmonium exotic charmonium

47 47 K. Peters - Status of QCD Exotics BES BEPC2 BEPC2 will operate as τcf and synchrotron light source Start of operation 2007

48 48 K. Peters - Status of QCD Exotics BES III Physics Performance Example J/ψ  ρ 0 ηπ 0 Well identified ρ(1390) ρ(2300) via partial wave analysis


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