The meson landscape Scalars and Glue in Strong QCD New states beyond Weird baryons: pentaquark problems “Diquarks,Tetraquarks, Pentaquarks and no quarks” 1 Diquarks, Tetraquarks, and no quarks (but no pentaquarks) “Exotics: what needs to be measured”

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Physics Problem: How to get the car out of the water?

Use a tow truck!

A closer look to check its all OK?

Physics Problem: Part 2: How to get the tow truck out of the water?

….. use a bigger tow truck……

Physics Problem Part 3: How to get…… …out of the water.

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IDEAS 1. Quarks, Chromostatics and Glueballs 2. Strong QCD, flux tubes and hybrids PHENOMENOLOGY 3. Scalar glueball: whats the evidence? 4. Hybrids and Tetraquarks 5. Hybrid charmonium??

But first: A taster of the current charmonium puzzle

Belle e+e- to + X ???

e+e- \to psi pi pi BaBar sees new vector cc* Y(4260)

Y(4260) = Non resonant S-wave threshold Y(4260) Three Possibilities Experimental distinctions….later

1.HOW QUARKS BEHAVE CHROMOSTATICS and glueballs

+ + Quarks carry any of three “colour” charges +

Antiquarks carry any of three “colour” charges but negative _ _ _

Now use familiar rules “Like charges (colours) repel; opposite (colours) attract”

Now use familiar rules “Like charges (colours) repel; opposite (colours) attract” + _ Makes a “meson”. Simplest “chromostatic” analogue of electrostatic positronium

The THREE colours enable quarks to attract one another making BARYONS (e.g. the proton)

baryon

A diquark Can attract an anti-diquark Making a meson that is a tetraquark

How can we tell if its this Or this? + - (later)

Colour charge Baryons Nucleus Electric charge Atoms Molecules Quantum Electrodynamics: QED Quantum Chromodynamics: QCD Interaction of electric charges and photons Interaction of colour charges and gluons

q q Gluon br* Like QED as far as pert theory concerned Strong at long range/low energy Need lattice QCD and models based on this Gluon is coloured Carries the “charge”

Gluon bg*Gluon b*g Colour singlet glueball (Strong QCD more complicted than this OgE example)

Glueballs spectrum from Lattice Far away from qq* lowest multiplets… except for 0++ what can be said about glueballs?

2.Strong QCD: FLUX TUBES and HYBRIDS

QCD inspired potential for heavy QQ*

2S: S: D: Quarkonium template: qq* L + S (= 0,1) =J L=0 L=1L=2 1P:

2S: 1- 1S: 1- 1D: Quarkonium template: Scalar qq* is canonical

2S: 1- 1S: 1- 1D:  cc*) Narrow below MM threshold

2S: 1- 1S: 1- 1D:  cc*) Lattice QCD: Linear: Flux tube…..implies…

flux-tube degrees-of-freedom c.m. e.g. p=1

flux-tube degrees-of-freedom c.m. e.g. p=1 Costs about 1 to 1.5GeV energy to excite phonon “pi/R” Hybrid 2GeV; Hybrid 4-4.5GeV

Gluonic hybrid mesons c.m. e.g. p=1 Exciting the flux tube 2006:Lattice QCD seems to confirm flux tube model predictions !

Lattice: signals: resonant? hybrid or molecule? E1 photoproduction of hybrids gamma p to n H^+ \sim 50% relative to conventional mesons (Isgur; FC Dudek) 2+- also expected. Diffractive Photoproduction!! Should exceed 1-+ strength

Lattice: also expected. Diffractive Photoproduction!! Should exceed 1-+ strength

flux-tube degrees-of-freedom c.m. e.g. p=1 are new degrees-of-freedom, not present in the quark model. Isgur showed that they have measurable effects on conventional states Close Dudek: E1 excitation of hybrids = r^2 meson: Cabibbo Radicatti (Lattice only now beginning to look at this)

flux-tube breaking and decays c.m. e.g. p=1 Break tube: S+P states yes; S+S suppressed 1-+ \to pi b_1:pi f_1 = 4:1 and big FC Page95

flux-tube breaking and decays c.m. e.g. p=1 Break tube: S+P states yes; S+S suppressed 1-+ \to pi b_1:pi f_1 = 4:1 and big FC Page95 QCD Lattice 06: Michael+McNeile confirm this !! S-wave decay amplitude at threshold agree flux tube prediction Beware naïve comparison of widths Implies FT model estimates somehow mimic strong QCD

2S: 1- 1S: 1- 1D:  cc*) Narrow below MM threshold

2S: 1- 1S: 1- 1D:  cc*) Narrow below MM threshold Either no G with these JPC in this region ( <eta_c) (1– 3.8Gev ~ psiprime?) or don’t couple strongly to G

Glueballs spectrum from Lattice

Glueballs also predicted: Strong QCD spectrum from Lattice Far away from qq* lowest multiplets… except for 0++ Only scalar glueball below 2 GeV

2S: 1- 1S: 1- 1D: / I=1 vector : I=0 nn*; ss* / / Problem of nn* ss* flavour mixing Clean below S-wave MM thresholds And no prominent G expected

2S: 1- 1S: 1- 1D: / I=1 vector : I=0 nn*; ss* / / /1500/ Problem of nn* ss* flavour mixing

2S: 1- 1S: 1- 1D: I=1 vector : I=0 J P = / / /1500/ /600

2S: 1- 1S: 1- 1D: I=1 vector : I=0 J P = / / /1500/ /600 [qq][q*q*]

2S: 1- 1S: 1- 1D: I=1 vector : I=0 J P = / / /1500/ /600 ? qq* + Glueball Lattice G =1.6 \pm

2S: 1- 1S: 1- 1D: I=1 vector : I=0 J P = / / /1500/ /600 ? qq* + Glueball Lattice G =1.6 \pm Data do not imply G But given lattice and qq* Does consistent pic emerge? Can data eliminate it; or even make it robust?

3.Scalar Glueball: WHATS the EVIDENCE?

Glueballs also predicted: Strong QCD spectrum from Lattice Far away from qq* lowest multiplets… except for 0++ Only scalar glueball below 2 GeV

2S: 1- 1S: 1- 1D: / I=1 vector : I=0 nn*; ss* / / /1500/ Problem of nn* ss* flavour mixing

Scalar Glueball and Mixing s n G

Meson s n G

Scalar Glueball and Mixing Meson G ss* nn* s n G LEAR/WA102 Meson pair decays

Meson G ss* nn* s n meson decays LEAR/ WA102 FC Kirk Scalar Glueball and Mixing a simple example for expt to rule out Nontrivial correlation with relative masses heavy l light middle

Scalar Glueball and Mixing: how to measure flavour state Meson G ss* nn* s n

Scalar Glueball and Mixing Meson G ss* nn* s n

Coming soon from BES and CLEO-c A flavour filter for mesons and glueballs >1 billion1000 per meson Challenge: Turn Lattice QCD Glueball spectrum into physics

Glueballs and central production

High energy; pomeron; glue(balls)

Glueballs and central production G Idea: Robson, FC 77

Glueballs and central production Gqq* Reality: qq* (also) produced How to separate G and qq*? FC Kirk Schuler 97-00

Two configurations for same t1,t2 c.m picture G/qq* G p_T(1)-p_T(2) = “big” p_T(1)-p_T(2) = “small”

Two configurations for same t1,t2 lab picture p_T(1)-p_T(2) = “big” p_T(1)-p_T(2) = “small” 1beam 2 target 1beam 2target

Two configurations for same t1,t2 lab picture They are related by….. …Phi rotation 1beam 2 target 1beam 2target

Rich J^{PC} dependence 0^{-+} 1^{- -} 1^{++} 2^{- +}

Rich J^{PC} dependence 0^{++} 2^{++}

0^{-+}:Eta’(960) phi and t distributions gg fusion or any vector vector sin^2(phi)… …and vanish as t \to 0

Also explains Eta_2(1645) phi and t

And changing behaviour of 1^{++} f1(1285) t1-t2<0.2 t1-t2>0.4 All t

So qq* “explained” Pomeron transforms like vector gluon gluon fusion? (details suggest more complicated) … are “explained” but for 0++ and 2++ something weird is happening

Central Production pp \to pMp 0+ and 2+ qq* G ?