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Exotics as a Probe of Confinement

QCD Exotics – Past, Present and Future. Exotics as a Probe of Confinement. Curtis A. Meyer Carnegie Mellon University. The beginning of time. The strong force and QCD. C o l o r confinement. Spectroscopy. Lattice QCD. Finding Gluonic Hadrons. Confinement.

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Exotics as a Probe of Confinement

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  1. QCD Exotics – Past, Present and Future Exotics as a Probe of Confinement Curtis A. Meyer Carnegie Mellon University ODU Colloquium

  2. The beginning of time. The strong force and QCD Color confinement Spectroscopy Lattice QCD Finding Gluonic Hadrons Confinement Outline ODU Colloquium

  3. of The Universe The First Seconds ODU Colloquium

  4. Quark Gluon Plasma For a period from about 10-12 s to 10-6 s the universe contained a plasma of quarks, anti quarks and gluons. Relativistic Heavy Ion Collisions are trying to produce this state of matter in collisions ODU Colloquium

  5. Confinement From about 10-6 s on, the quark and anti quarks became confined inside of Hadronic matter. At the age of 1s, only protons and neutrons remained. The gluons produce the 16ton force that holds the hadrons together. Mesons Baryons ODU Colloquium

  6. The Formation of Nuclei By the old age of three minutes, the formation of low mass nuclei was essentially complete. Primordial hydrogen, deuterium, helium and a few other light nuclei now exist. It will be nearly a half a million years before neutral atoms will dominate matter. ODU Colloquium

  7. Dynamics Quantum Chromo The rules that govern how the quarks froze out into hadrons are given by QCD. Just like atoms are electrically neutral, hadrons have to be neutral. Color Charge Three charges calledRED, BLUEand GREEN, and three anti colors. The objects that form have to be color neutral: ODU Colloquium

  8. R G G R R G R R G B B G Gluons Carry the Force Meson Meson The exchange of gluons is continually changing the Individual colors of the quarks, but the overall Color remains neutral Time ODU Colloquium

  9. R G G R R G R R G B B G Gluons Carry the Force Meson Meson The exchange of gluons is continually changing the Individual colors of the quarks, but the overall Color remains neutral Time ODU Colloquium

  10. R G G R R G R R G B B G Gluons Carry the Force Meson Meson The exchange of gluons is continually changing the Individual colors of the quarks, but the overall Color remains neutral Time Gluons produce the forces that confine the quarks, but the gluons do not appear to be needed to understand normal hadrons ODU Colloquium

  11. R R G B G R G B R R 1 color neutral 8 colored objects R 3 Colors 3 Anti Colors G R R G B B G 8 Gluons Gluon Interactions self-interaction of gluons leads to both interesting behavior of QCD, and its extreme complications. ODU Colloquium

  12. Flux Tubes ODU Colloquium

  13. Flux Tubes ColorField: Because of self interaction, confining flux tubes form between static color charges Confinement arises from flux tubes and their excitation leads to a new spectrum of mesons ODU Colloquium

  14. Quark Confinement • quarks can never be isolated • linearly rising potential • separation of quark from antiquark takes an infinite amount of energy • gluon flux breaks, new quark-antiquark pair produced ODU Colloquium

  15. Strong QCD white See and systems. white Allowed systems: , , Color singlet objects observed in nature: Nominally, glue is not needed to describe hadrons. Focus on “light-quark mesons” quark-antiquark states glueballs hybrids ODU Colloquium

  16. e+ e- Spectroscopy A probe of QED Positronium Spin: S=S1+S2=(0,1) Orbital Angular Momentum: L=0,1,2,… Total Spin: J=L+S L=0, S=0 : J=0 L=0, S=1 : J=1 L=1 , S=0 : J=1 L=1, S=1 : J=0,1,2 …… Reflection in a mirror: Parity: P=-(-1)(L) Particle<->Antiparticle: Charge Conjugation: C=(-1)(L+S) Notation: J(PC) 0-+, 1--, 1+-, 0++, 1++, 2++ (2S+1)LJ 1S0, 3S1, 1P1, 3P0, 3P1, 3P2,… ODU Colloquium

  17. L=3 Consider the three lightest quarks 4++ 3++ q q 2++ 9 Combinations L=2 3+- 3-- 2-- 1-- 2-+ L=1 2++ 1++ S=1 S=0 0++ L=0 1+- 1-- 0-+ Spectroscopy and QCD Quarkonium Mesons radial ODU Colloquium

  18. Mesons L=3 4++ 3++ q q 2++ L=2 3+- 3-- 2-- 1-- 2-+ L=1 2++ 1++ S=1 S=0 0++ L=0 1+- 1-- 0-+ Spectroscopy an QCD Quarkonium Mesons come in Nonets of the same JPC Quantum Numbers r,K*,w,f p,K,h,h’ a,K,f,f’ b,K,h,h’ SU(3) is broken Last two members mix r,K*,w,f p,K,h,h’ ODU Colloquium

  19. SU(3) physical states Quantum Mechanical Mixing States with the same quantum numbers mix: Ideal Mixing: ODU Colloquium

  20. Quarkonium Nothing to do with Glue! L=3 4++ 3++ q q 2++ L=2 3+- 3-- 2-- 1-- 2-+ L=1 2++ 1++ S=1 S=0 0++ L=0 1+- 1-- 0-+ Spectroscopy an QCD Quarkonium Mesons Allowed JPC Quantum numbers: 0-- 0+- 1-+ 2+- 3-+ 4+- 5-+ 0++ 0-+ 1–- 1++ 1+- 2-- 2++ 2-+ 3-- 3++ 3+- 4-- 4++ 4-+ 5-- 5++ 5+- Exotic Quantum Numbers non quark-antiquark description ODU Colloquium

  21. Glueball Predictions qq Mesons 2 – + 0 – + 2 + + 2.5 2.0 1.5 0 + + 1.0 L = 0 1 2 3 4 Particles that only contain gluons All of these are normal quark-antiquark quantum numbers. Glueballs ODU Colloquium

  22. Lattice QCD Predictions Gluons can bind to form glueballs EM analogue: massive globs of pure light. Lattice QCD predicts masses The lightest glueballs have “normal” quantum numbers. Glueballs will Q.M. mix The observed states will be mixed with normal mesons. Strong experimental evidence For the lightest state. ODU Colloquium

  23. Identification of Glueballs Glueballs should decay in a flavor-blind fashion. Lightest Glueball predicted near two states of same Q.N.. “Over population” Predict 2, see 3 states Production Mechanisms: Certain are expected to by Glue-rich, others are Glue-poor. Where do you see them? Proton-antiproton Central Production J/y decays ODU Colloquium

  24. Crystal Barrel Results: antiproton-proton annihilation at rest f0(1500) app, hh, hh’, KK, 4p Discovery of the f0(1500) f0(1370) a4p Solidified the f0(1370) Establishes the scalar nonet Discovery of the a0(1450) Crystal Barrel Results 250,000 hhp0 Events 700,000 p0p0p0 Events f2(1565)+s f0(1500) f2(1270) f0(980) f0(1500) ODU Colloquium

  25. Wa102 Results CERN experiment colliding p on a hydrogen target. Central Production Experiment Recent comprehensive data set and a coupled channel analysis. ODU Colloquium

  26. A Model for Mixing meson Glueball meson meson meson meson Glueball meson meson 1 r2 r3 flavor blind? r Solve for mixing scheme F.Close: hep-ph/0103173 ODU Colloquium

  27. Glueballs f0(1710) f0(1500) Glueball spread over 3 mesons a0(1450) K*0(1430) f0(1370) a0(980) f0(980) Experimental Evidence Scalar (0++) Glueball and two nearby mesons are mixed. Are there other glueballs? ODU Colloquium

  28. Higher Mass Glueballs? Part of the BES-III program will be to search for glueballs in radiative J/ decays. Lattice predicts that the 2++ and the 0-+ are the next two, with masses just above 2GeV/c2. Radial Excitations of the 2++ ground state L=3 2++ States + Radial excitations f2(1950), f2(2010), f2(2300), f2(2340)… 2’nd Radial Excitations of the  and ’, perhaps a bit cleaner environment! (I would Not count on it though….) I expect this to be very challenging. ODU Colloquium

  29. Hybrid Meson Predictions qq Mesons S=1 2.5 2 + – 2 – + 2.0 1 – – Hybrids 1– + 1 + – exotic nonets 1 + + 1.5 0 + – 0 – + 1.0 L = 0 1 2 3 4 qqg Flux-tube model: 8 degenerate nonets 1++,1-- 0-+,0+-,1-+,1+-,2-+,2+- ~1.9 GeV/c2 S=0 Start with S=0 1++ & 1-- Start with S=1 0-+ & 0+- 1-+ & 1+- 2-+ & 2+- ODU Colloquium

  30. excited flux-tube m=1 ground-state flux-tube m=0 linear potential QCD Potential Gluonic Excitations provide an experimental measurement of the excited QCD potential. Observations of the nonets on the excited potentials are the best experimental signal of gluonic excitations. ODU Colloquium

  31. Hybrid Predictions Flux-tube model: 8 degenerate nonets 1++,1-- 0-+,0+-,1-+,1+-,2-+,2+- ~1.9 GeV/c2 S=0 S=1 Lattice calculations --- 1-+ nonet is the lightest UKQCD (97) 1.87 0.20 MILC (97) 1.97 0.30 MILC (99) 2.11 0.10 Lacock(99) 1.90 0.20 Mei(02) 2.01 0.10 Bernard(04) 1.792§0.139 1-+ 1.9+/- 0.2 2+- 2.0+/- 0.11 0+- 2.3+/- 0.6 In the charmonium sector: 1-+ 4.39 0.08 0+- 4.61 0.11 Splitting = 0.20 ODU Colloquium

  32. Decay Predictions Meson Meson Meson Lglue Looking for Hybrids Analysis Method Partial Wave Analysis Fit n-D angular distributions Fit Models of production and decay of resonances. Angular momentum in the gluon flux stays confined. This leads to complicated multi-particle final states. Detector needs to be very good. ODU Colloquium

  33. Hybrids New York Times, Sept. 2, 1997 Experimental Evidence Exotic Mesons 1-+ mass 1.4 E852 BNL ’97 CBAR CERN ’97 Too light Not Consistent Possible rescattering (?) Decays are wrong (?) Not a Hybrid ODU Colloquium

  34. to partial wave analysis suggests E852 Results At 18 GeV/c ODU Colloquium

  35. Correlation of Phase & Intensity Leakage From Non-exotic Wave due to imperfectly understood acceptance An Exotic Signal Exotic Signal p1(1600) 3p m=1593+-8+28-47G=168+-20+150-12 ph’ m=1597+-10+45-10G=340+-40+-50 ODU Colloquium

  36. In Other Channels E852 Results 1-+ in ’ p-p  ’-p at 18 GeV/c The 1(1600) is the Dominant signal in ’. Mass = 1.5970.010 GeV Width = 0.3400.040 GeV 1(1600)  ’ ODU Colloquium

  37. In Other Channels E852 Results 1-+ in f1 and b1 p-p  +--p p-p  w0-p 1(1600)  b1 1(1600)  f1 Mass=1.7090.024 GeV Width=0.4030.08 GeV In both b1 and f1, observe Excess intensity at about 2GeV/c2. Mass ~ 2.00 GeV, Width ~ 0.2 to 0.3 GeV Mass = 1.6870.011 GeV Width = 0.2060.03 GeV ODU Colloquium

  38. New Analysis No Evidence for the 1(1670) Dzierba et. al. PRD 73 (2006) 10 times statistics in each of two channels. Get a better description of the data via moments comparison Add 2(1670)-> (L=3) Add 2(1670)->3 Add 2(1670)-> ()S Add a3 decays Add a4(2040) ODU Colloquium

  39. Exotic Signals p1 IG(JPC)=1-(1-+) K1 IG(JPC)= ½ (1-) h’1 IG(JPC)=0+(1-+) h1 IG(JPC)=0+(1-+) 1(1400)Width ~ 0.3 GeV, Decays: only  weak signal in p production (scattering??) strong signal in antiproton-deuterium. NOT A HYBRID Does this exist? 1(1600) Width ~ 0.16 GeV, Decays ,’,(b1) Only seen in p production, (E852 + VES) 1(2000) Weak evidence in preferred hybrid modes f1 and b1 The right place. Needs confirmation. ODU Colloquium

  40. Hybrid Nonets New York Times, Sept. 2, 1997 Levels Built on normal mesons Experimental Evidence 1-+ Establish other Nonets: 0+-1-+ 2+- Identify other states in nonet to establish hybrid ODU Colloquium

  41. Jefferson Lab Upgrade ODU Colloquium

  42. Jefferson Lab Upgrade Upgrade magnets and power supplies CHL-2 ODU Colloquium

  43. The GlueX Experiment ODU Colloquium

  44. How to Produce Hybrids Beams of photons may be a more natural way to create hybrid mesons. Simple QN counting leads to the exotic mesons There is almost no data for photon beams at these energies. GlueX will increase samples by 3-4 orders of magnitude. ODU Colloquium

  45. Incoherent & coherent spectrum 40% polarization in peak collimated tagged with 0.1% resolution 12 GeV electrons Bremsstrahlung Coherent flux This technique provides requisite energy, flux and polarization Linearly polarized photons out electrons in spectrometer diamond crystal photon energy (GeV) ODU Colloquium

  46. Exotics In Photoproduction X g e N N p1 IG(JPC)=1-(1-+) K1 IG(JPC)= ½ (1-) g  ,, h’1 IG(JPC)=0+(1-+) h1 IG(JPC)=0+(1-+) 1-+ nonet Need to establish nonet nature of exotics: 0 Need to establish more than one nonet: 0+- 1-+ 2+- ODU Colloquium

  47. Lattice QCD potentials Gluonic Hadrons and Confinement What are the light quark Potentials doing? DE Potentials corresponding To excited states of glue. Non-gluonic mesons – ground state glue. ODU Colloquium

  48. The quest to understand confinement and the strong force is about to make great leaps forward. Conclusions Advances in theory and computing will soon allow us to solve QCD and understand the role of glue. The definitive experiments to confirm or refute our expectations are being built. The synchronized advances in both areas will allow us to finally understand QCD and confinement. ODU Colloquium

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