The meson landscape Scalars and Glue in Strong QCD New states beyond Weird baryons: pentaquark problems Frank Close ICHEP04 “Diquarks,Tetraquarks, Pentaquarks.

The meson landscape

Scalars and Glue in Strong QCD

New states beyond

Weird baryons: pentaquark problems

Frank CloseICHEP04

“Diquarks,Tetraquarks, Pentaquarks and no quarks”

1

2S: 1-

1S: 1-

1D: 1-

2+

1+

0+

9460

10023

9860

9893

9913

3686

3097

3415

3510

3556

3772

cc*)

2S: 1-

1S: 1-

1D: 1-

2+

1+

0+

9460

10023

9860

9893

9913

3686

3097

3415

3510

3556

3772

cc*)

Radiative E1transitionsprecision beyond simple cc*

Hadronic decays entréeto gluonic light hadrons1++ to pi and exotic 1-+ (hybrid) BES;CLEOc

Glue-gammainterference -90 degrees(Wang)And 2S-1D mixing (Rosner)Solution to suppressed hadronic modesBES; CLEOc

2S: 1-

1S: 1-

1D: 1-

2+

1+

0+

770

1460

1700

I=1 vector : I=0 JP = 2+ 1+ 0+

1270/1525

1285/1530

(nn* ss*)

2S: 1-

1S: 1-

1D: 1-

2+

1+

0+

770

1460

1700

I=1 vector : I=0 JP = 2+ 1+ 0+

1270/1525

1285/1530

(nn* ss*)

qq* seed dominatesIf no S-wave mesonchannels are open.

S-wave hadrons hide qq*

Production channelsgive different impressionsof Fock state

Big problem for scalarswhich couple to pi pi etcin s-wave even though qq*is in p-wave

2S: 1-

1S: 1-

1D: 1-

2+

1+

0+

770

1460

1700

I=1 vector : I=0 JP = 2+ 1+ 0+

1270/1525

1285/1530

1370/1500/1710/1790

6

2S: 1-

1S: 1-

1D: 1-

2+

1+

0+

770

1460

1700

I=1 vector : I=0 JP = 2+ 1+ 0+

1270/1525

1285/1530

980/600

1370/1500/1710/1790

7

2S: 1-

1S: 1-

1D: 1-

2+

1+

0+

770

1460

1700

I=1 vector : I=0 JP = 2+ 1+ 0+

1270/1525

1285/1530

0+ 1370/1500/1710/1790

980/600

? qq* + Glueball

Lattice G =1.6 \pm

8

Scalar Glueball and Mixing

s

n

G

9

Scalar Glueball and Mixinga simple example for expt to rule out

Meson

1710

1500

1370

s

n

G

10

Meson G ss* nn*

1710 0.39 0.91 0.15

1500 - 0.65 0.33 - 0.70

1370 - 0.69 0.15 0.70

s

n

0- 0- meson decays LEAR/WA102

Scalar Glueball and Mixinga simple example for expt to rule out

11

Coming soon from BES and CLEO-c

A flavour filter for 0++ 0-+ 2++ (and 1++)

mesons glueballs et al

>1 billion 1000 per meson

Challenge: Turn Lattice QCD Glueball spectrum into physics

12

2S: 1-

1S: 1-

1D: 1-

2+

1+

0+

770

1460

1700

I=1 vector : I=0 JP = 2+ 1+ 0+

1270/1525

1285/1530

0+ 1370/1500/1710/1790

980/600

? qq* + Glueball

[qq][q*q*] seed and/orS-wave mesons

13

Production chooses easiest route:interpretation needs care

980 (uu*+dd*)ss*980 (uu*- dd*)ss*

KLOE

phiK

K

gamma

S wave KK into 0++ long range wavefunctionSays little about short range QCDwavefunction

e.g.

Contrast Xi_c(3400) \to f0(980)f0(980) (BES) and Z decays which feed f0(980) via “easiest” qq* like other hadrons

New states outside the quark

model:

cc* X(3872) anomalous charmonium

15

A new narrow charmonium state

B decay = a new source of charmonium

Charmonium candidates2- 3- radial1+ are narrow below DD*

Mass, width, angular dist etcall inconsistent with cc*

Standard cc* theory wrong?Or is X(3872) not simple cc*?

16

DD* molecule “tetraquark” Mass same as neutral thresholdto better than 1 in 10,000

cuc*u* S-wave JPC = 1++

= isospin maximally broken

Close+PageTornqvistSwanson

Test: X \to K+K-\pi>> K0K0\pi

CLEOc/BES test for 1++ 3550 also

Rho?

Also psi omega: Belle

cc*1++ 3550; 1++* 3950:

DD* (neutral) thresholdPsi rho; psi omega S-wave 1++ mesons

P-wave cc*

D

D*

psi

uu* vector

D

D*

D*

D

pi

Energy degeneracy will drivethis >> model details.

Psi rho:psi omega \sim 1Deviations = dynamics

Specific model: Swanson

Decays driven by meson-meson wavefunction

Production by cc* residue: like psiprime

S-wave meson-meson beats P-wave qq* (continued)18

Mass coincidenceonly happens withCharm, not strange or bottom

X(3872) summary

cc* 1++ seedMeson-meson S-wave dominant

19

K

Lambda

eta

N

S-wave baryon-meson beats P-wave qqq

Baryon S_{11} is qqq p-wave but prefers N-etaRescatters to K Lambda (e.g. BES, previous talk)

A Baryon analogue from BES ? (Shan Jin talk)20

Psi to gamma p pbar enhancement/bound state also?

New states outside the quark

model:

cs* (2317;2460;2635)

22

Novel states in

• 0+ 2317

• 1+ 2460

• J^P=?… 2632

ultralite cs*; DK molecule

Isospin violation as below DK threshold

cs* 1- radial (nodes); mix with ^3D_1 = Xcs*uu* (Iso violation); = X = artefact ?

Narrow. Anomalous decays “anti” phase space

23

(also M.Nowak et al, HADRON2003)

Why in cs*?

Which 1+?25601+

243MeV

25

DK

D*K

26

Whatever makes scalar f_0(980) light (= just below KK)(compared to qq* p-wave)

Probably makes scalar 2317 light (= just below DK)(compared to qq* p-wave)

…and 2460 axial light (just below D*K)

Production by easiest route: cs* residueDecays driven by di-meson DK D*K

TEST: 1+ \to 0+ \gamma (M1)

D*K \to DK \gamma = D* \to D \gamma

S-wave meson-meson beats P-wave qq* (continued)27

Another novel state in

• J^P=? 2632

Narrow. Anomalous decays “anti” phase space

28

Novel states in

• J^P=0+,1-… 2632

cs* 1- radial (nodes); mix with ^3D_1

cs*uu* (Iso violation);

cqs*q* + css*s*(tetraquark in 15_f)

Narrow. Anomalous decays “anti” phase space

29

Novel states in

• J^P=0+,1-… 2632

cs* 1- radial (nodes); mix with ^3D_1 doesn’t work

cs*uu* (Iso violation); D_s + pi^o D_s + gamma gamma = NO

cqs*q* + css*s*(tetraquark in 15_f)6_f more attractive; D_s gamma gamma = NO

Narrow. Anomalous decays “anti” phase space

30

2632 would be here31

D_{sJ} summary

2317/2460: cs* 0+ 1+ seedsMeson-meson S-wave DK D*K

Dynamics like 0++(980)

2632: artefact

32

Some Reflections on Pentaquarks

33

½+ Strangeness +1 baryon mass 1540MeV narrow width

Predicted!!! DPP

In chiral soliton model with unusual assumptions

Narrow width an enigmaMass a problemProduction mechanism unknown

n.b. expt has not established ½+It might not exist!

34

u d u d

Q*

u d

Jaffe Wilczek

ud udQ*

Karliner Lipkin

L=1

L=1

Diquark attractionsfor unlike flavours = basis for pentaquark models(has not been demonstrated how low mass scalar diquarks form, stability, effective bosons, consistency with other hadron spectroscopy… etc. = ?)

Pentaquarks(if they exist)= strong QCDcorrelations

ArndtBuccellaCarlsonDyakanovEllisFaberGianniniHuangInoueJaffeKarlinerLipkinMaltmanNussinovOhPolyakovQiangRosnerStechTrillingUVenezianoWilczekXiangYangZhu

If Theta doesn’t exist,then these (and many other theorists)should be congratulated on their creativity

Mass

37

+ Baryon

DPP original M=(1890-180Y)MeV and revised

Linear only for 10*. Mixing with 8 complicates.Mass formulae beware |S| versus S. Strange quark costs too muchNo simple map onto pentaquark

(LEPS)

nK

Anomalies with Theta Mass?

0SpK

F. Close and Q. Zhao, hep-ph/040407539

Mass Fitted. Not calculated

Dyakanov Petrov Polyakov DPP assumed N(1710) in 10bar

Jaffe Wilzcek JW assumed N(1440) as (ud)(ud)dbar

X mass formula bizarre: q_5 10bar mass gap 1/3 m_s

X pure 10bar not photoproduced from p

X width 300MeVX gamma n:gamma p = radial 56plet qqqX Delta(1670) partner

Karliner Lipkin KL assume cs* 200MeV orbital to set scale

X spin averaged cs* costs 500MeV, Theta= 1800MeV

u d u d

Q*

u d

Jaffe Wilczek

ud udQ*

Karliner Lipkin

Q* \to (ud) = anomalous deuteron

(ud) \to Q* 10bar mesons

P-wave 1-+ etc? e.g.Chung KlemptWidths? FC Dudek Burns

Forces ud very light and L largeWhat mechanism?

What if……..?

41

Width

42

Chiral Soliton Theta-N-K Coupling involves threeunknowns A; B; C

B F/DSet scale with g(10*) = 1-B-C

NRCQM: F/D=2/3 B=1/5 C= 4/5 g(10*)=0

g(10*)

C

After Ellis Karliner Prasalowicz

Width

Width < 10 MeV direct experiments <1MeV Cahn Trilling; Nussinov;…

3/2- Lambda(1520) KN width 7 MeV

Jaffe Wilzcek; Jennings Maltman; Carlson et al; Close Dudek;Buccella Stora

Color flavor spin overlap suppression > 24

X D wave; P-wave Lambda1600 is 100 MeVX needs qq* creation whereas qqqqq* falls apart

X color killed by soft gluon exchangeX spin flip costs littleX flavor killed by rearrangement

Stech et al; Dudek; Carlson et al

Spatial overlap suppression

X no dynamical proof Stech

? Strong color-spin forces (Dudek) + Stech model….?44

Width < 10 MeV experiments <1MeV Cahn Trilling; Nussinov;…

Decouples from KN (small width)

Strong coupling to something (strong production) How is Theta produced?

………………enigma

45

Production

46

Several experimental limits in hadron production

Some not restrictive yet e.g. psi(3095) to Theta Thetabar (=3080) versus LambdaLambdabar (1/100)or can be “explained away” e.g. psiprime sees some channels reduced and this is another one; big price to produce 10 q and q* etc.

My opinion (this week)Limits in high statistics look impressive.Onus is on supporters to explain them away or find a loophole

……….example of a possible loophole Lipkin Karliner next

47

Why seen in photons but not in high statistics hadrons?

CLAS: Theta+K = N*(2.4GeV) (24ev/10bgnd)

Suppose N*(uddss*) and gamma provides the ss*

Problems

CLAS see in

gammapi

K

Theta

pi

NN*

No memory of gamma(ss*); should apply to hadrons too…..why not CDF?

SPring8 and CLAS1 too low E(gamma) to make 2.4GeV N*48

The Mystery of the Sigma_5

• The case of the dog that didn’t bark

(Sherlock Holmes)

If Theta is real, why isnt Sigma_5

(or Sigma* ½+ 1660) also seen?

49

Note pKs can be + or +

Decays Dyakanov Petrov Polyakov; Close Dudek; Oh Kim Lee

generalises

50

Gamma N \to K ThetaAssuming s,t,u and contact diagrams

Gamma N \to K Sigma5

FC-Q Zhao

0.5

53

M(pKs)

HERMES

5.3~6.1~)1520(*R

Absence of Sigma_5, or even Sigma(1660)

in experiments that claim Theta is a worry.

Dzierba Szczepaniak TeigeFake Peaks in gamma N

N

gamma

N

a2/rho3

55

Dzierba Szczepaniak Teige

Fake Peaks in gamma N

N a2/rho3

N

K K

D/F wave decay forward backto KKbar

a2/rho3 gives charge asymmetry

Same velocity NK mass 1440“real” kinematics broadens hump….

Dzierba Szczepaniak Teige

One is real (CLAS)Three are fake

Can you tell which?

(LEPS)

nK

Could this also explain different nK+ and pKs masses?

0SpK

F. Close and Q. Zhao, hep-ph/0404075

Show Dalitz plots!!

Different Q valuesfor charged neutralfeed into mass offake Theta?

Paradoxes; Enigmas; Hints of unreality

How is Theta produced?Why seen in low statistics photoproduction but not in high statistics hadroproduction?

Decouples from KN (small width)Strong coupling to something (strong production)

Why does mass vary?real (dynamic clue); statistics (non existence clue)

Cascades (exotics) studied since BQM Beware!

K-Theta+ why no K+Sigma-Ks Theta+ why no Ks Sigma+

Why is productionTheta/Sigma(1660)= infinity?

59

CONCLUSION

Have Weird Multiquark Demons been found?

Is there a 1 MeV wide, S=+1 baryon at 1540 MeV?

If NO this is testament to the ingenuity of theorists whosemodels can explain it even if it doesn’t exist.

Lattice QCD is almost unique in not having

definitively disproved that such a state does not exist.

60

CONCLUSIONPrecision and variety = Beyond qq*

Strong Glue in QCD:Glueballs mix; psi to gam gam V opportunity.exotic hybrids emerging; Xi_{c1} decays opportunity

Multiquarks/Molecules:X(3872) 1++ molecule (to be disproved)

Ds(2317;2460) 0+ and 1+: cs* or DK/DK* (need to determine)

Ds(2635) artefact (to be disproved)

Pentaquarks/Theta:Artefact or Strong QCD very profoundOpportunity for lattice to realise its investment

CONCLUSION

• YES

• No

• Keep searching

Have Weird Multiquark Demonsbeen found?

Democratic voting paper/Florida counting principle

With thanks to the organisers,

the scientific secretaries

and the IHEP students who have madeour time in Beijing so enjoyable

This slide sponsored by Oxford University Press

• A Very Short Introduction to Particle Physics

A little red pocket book with no equations

for physics undergraduates and your partners

by

Frank Close

• 10 dollars at amazon.com now

Central Production pp \to pMp 0+ and 2+

qq* G ?

Compare e+e- \to e+(qq*)e-

A new narrow charmonium state

B decay = a new source of charmonium

Standard cc* theory wrong?Or is X(3872) not simple cc*?

Charmonium problems

A conjecture: T.Barnes, F.E.Close, H.J.Lipkin, hep-ph/0305025, PRD.

Reminiscent of Weinstein and Isgur’s KKbar molecules,bound by level repulsion of the KKbar continuum against higher mass qqbar 0+ scalars at ca. 1.3 GeV.

MassLow “N”(940) + “K”(495) (L=1) = 115MeV

(ud)+(uds*) < “N+K” (L=1) = 200MeV Karliner Lipkin

2.592.56

2.32

2.11

1.97

1-

0+

Ds(cs*) spectrum

210

MassLow “N”(940) + “K”(495) (L=1) = 115MeV

(ud)+(uds*) < “N+K” (L=1) = 200MeV Karliner Lipkin

400-480

1-

0+

0-

1+

L=0

L=1

2+

2.55 -2.47

2.07

Spin averaged masses in multiplet

Theta = 1750-1830

Unique Isospin laboratory

I=3/2 and I=1/2 but for narrow states flavour wins:

=(dss)dd*

=(dss)uu*10MeV

(LEPS)

nK

MΘ

0SpK

0SpKnK

F. Close and Q. Zhao, hep-ph/0404075