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

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

1 The meson landscape Scalars and Glue in Strong QCD New states beyond Weird baryons: pentaquark problems Frank Close ICHEP04 “Diquarks,Tetraquarks, Pentaquarks and no quarks” 1

2 2S: 1- 1S: 1- 1D:  cc*)

3 2S: 1- 1S: 1- 1D:  cc*) Radiative E1 transitions precision beyond simple cc* Hadronic decays entrée to gluonic light hadrons 1++ to pi and exotic 1-+ (hybrid) BES;CLEOc Glue-gamma interference -90 degrees (Wang) And 2S-1D mixing (Rosner) Solution to suppressed hadronic modes BES; CLEOc

4 2S: 1- 1S: 1- 1D: I=1 vector : I=0 J P = / /1530 (nn* ss*)

5 2S: 1- 1S: 1- 1D: I=1 vector : I=0 J P = / /1530 (nn* ss*) qq* seed dominates If no S-wave meson channels are open. S-wave hadrons hide qq* Production channels give different impressions of Fock state Big problem for scalars which couple to pi pi etc in s-wave even though qq* is in p-wave

6 2S: 1- 1S: 1- 1D: I=1 vector : I=0 J P = / / /1500/1710/

7 2S: 1- 1S: 1- 1D: I=1 vector : I=0 J P = / / / /1500/1710/

8 2S: 1- 1S: 1- 1D: I=1 vector : I=0 J P = / / /1500/1710/ /600 ? qq* + Glueball Lattice G =1.6 \pm 8

9 Scalar Glueball and Mixing s n G 9

10 Scalar Glueball and Mixing a simple example for expt to rule out Meson s n G 10

11 Meson G ss* nn* s n meson decays LEAR/ WA102 Scalar Glueball and Mixing a simple example for expt to rule out 11

12 Coming soon from BES and CLEO-c A flavour filter for (and 1++) mesons glueballs et al >1 billion1000 per meson Challenge: Turn Lattice QCD Glueball spectrum into physics 12

13 2S: 1- 1S: 1- 1D: I=1 vector : I=0 J P = / / /1500/1710/ /600 ? qq* + Glueball [qq][q*q*] seed and/or S-wave mesons 13

14 Production chooses easiest route: interpretation needs care 980 (uu*+dd*)ss* 980 (uu*- dd*)ss* KLOE phi K K gamma S wave KK into 0++ long range wavefunction Says little about short range QCD wavefunction 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

15 New states outside the quark model: cc* X(3872) anomalous charmonium 15

16 A new narrow charmonium state B decay = a new source of charmonium Charmonium candidates radial 1+ are narrow below DD* Mass, width, angular dist etc all inconsistent with cc* Standard cc* theory wrong? Or is X(3872) not simple cc*? 16

17 DD* molecule “tetraquark” Mass same as neutral threshold to better than 1 in 10,000 cuc*u* S-wave J PC = 1 ++ = isospin maximally broken Close+Page Tornqvist Swanson Test: X \to K+K-\pi>> K0K0\pi CLEOc/BES test for also Rho? Also psi omega: Belle

18 cc* ; 1++* 3950: DD* (neutral) threshold Psi rho; psi omega S-wave 1++ mesons P-wave cc* D D* psi uu* vector D D* D pi Energy degeneracy will drive this >> model details. Psi rho:psi omega \sim 1 Deviations = 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 coincidence only happens with Charm, not strange or bottom

19 X(3872) summary cc* 1++ seed Meson-meson S-wave dominant 19

20 K Lambda eta N S-wave baryon-meson beats P-wave qqq Baryon S_{11} is qqq p-wave but prefers N-eta Rescatters 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?

21 New states outside the quark model: cs* (2317;2460;2635) 22

22 Novel states in J^P=?… 2632 ultralite cs*; DK molecule Isospin violation as below DK threshold cs* 1- radial (nodes); mix with ^3D_1 = X cs*uu* (Iso violation); = X = artefact ? Narrow. Anomalous decays “anti” phase space 23

23

24 (also M.Nowak et al, HADRON2003) Why in cs*? Which 1+? MeV 25

25 DK D*K 26

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* residue Decays 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

27 Another novel state in J^P=? 2632 Narrow. Anomalous decays “anti” phase space 28

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

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

30 2632 would be here 31

31 D_{sJ} summary 2317/2460: cs* seeds Meson-meson S-wave DK D*K Dynamics like 0++(980) 2632: artefact 32

32 Some Reflections on Pentaquarks 33

33 ½+ Strangeness +1 baryon mass 1540MeV narrow width Predicted!!! DPP In chiral soliton model with unusual assumptions Narrow width an enigma Mass a problem Production mechanism unknown n.b. expt has not established ½+ It might not exist! 34

34 u d u du d Q* u d Jaffe Wilczek udud udQ* Karliner Lipkin L=1 Diquark attractions for 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 QCD correlations

35 Arndt Buccella Carlson Dyakanov Ellis Faber Giannini Huang Inoue Jaffe Karliner Lipkin Maltman Nussinov Oh Polyakov Qiang Rosner Stech Trilling U Veneziano Wilczek Xiang Yang Zhu If Theta doesn’t exist, then these (and many other theorists) should be congratulated on their creativity

36 Mass 37

37  + Baryon DPP original M=( Y)MeV and revised Linear only for 10*. Mixing with 8 complicates. Mass formulae beware |S| versus S. Strange quark costs too much No simple map onto pentaquark

38 (LEPS) Anomalies with Theta Mass? F. Close and Q. Zhao, hep-ph/

39 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 300MeV X gamma n:gamma p = radial 56plet qqq X Delta(1670) partner Karliner Lipkin KL assume cs* 200MeV orbital to set scale X spin averaged cs* costs 500MeV, Theta= 1800MeV

40 u d u du d Q* u d Jaffe Wilczek udud udQ* Karliner Lipkin Q* \to (ud) = anomalous deuteron (ud) \to Q* 10bar mesons P-wave 1-+ etc? e.g. Chung Klempt Widths? FC Dudek Burns Forces ud very light and L large What mechanism? What if……..? 41

41 Width 42

42 Chiral Soliton Theta-N-K Coupling involves three unknowns A; B; C B F/D Set 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

43 < 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 MeV X needs qq* creation whereas qqqqq* falls apart X color killed by soft gluon exchange X spin flip costs little X 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

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

45 Production 46

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

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 gamma pi K Theta pi N N* 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

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

49 Note pK s can be  + or  + Decays Dyakanov Petrov Polyakov; Close Dudek; Oh Kim Lee generalises 50

50 Gamma N \to K Theta Assuming s,t,u and contact diagrams

51 Gamma N \to K Sigma5 FC-Q Zhao

52 0.5 53

53 M(pK s ) HERMES Absence of Sigma_5, or even Sigma(1660) in experiments that claim Theta is a worry.

54 Dzierba Szczepaniak Teige Fake Peaks in gamma N N gamma N a2/rho3 55

55 Dzierba Szczepaniak Teige Fake Peaks in gamma N N a2/rho3 N K K D/F wave decay forward back to KKbar a2/rho3 gives charge asymmetry Same velocity NK mass 1440 “real” kinematics broadens hump….

56 Dzierba Szczepaniak Teige One is real (CLAS) Three are fake Can you tell which?

57 (LEPS) Could this also explain different nK+ and pKs masses? F. Close and Q. Zhao, hep-ph/ Show Dalitz plots!! Different Q values for charged neutral feed into mass of fake Theta?

58 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 production Theta/Sigma(1660) = infinity? 59

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 whose models 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

60 CONCLUSION Precision 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 profound Opportunity for lattice to realise its investment

61 CONCLUSION YES No Keep searching Have Weird Multiquark Demons been found? Democratic voting paper/Florida counting principle

62 With thanks to the organisers, the scientific secretaries and the IHEP students who have made our time in Beijing so enjoyable

63 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

64

65 Central Production pp \to pMp 0+ and 2+ qq* G ? Compare e+e- \to e+(qq*)e-

66 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

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

68 Mass Low “N”(940) + “K”(495) (L=1) = 115MeV (ud)+(uds*) < “N+K” (L=1) = 200MeV Karliner Lipkin Ds(cs*) spectrum 210

69 Mass Low “N”(940) + “K”(495) (L=1) = 115MeV (ud)+(uds*) < “N+K” (L=1) = 200MeV Karliner Lipkin L=0 L= Spin averaged masses in multiplet Theta =

70 Unique Isospin laboratory I=3/2 and I=1/2 but for narrow states flavour wins: =(dss)dd* =(dss)uu* 10MeV

71 (LEPS) MΘMΘ F. Close and Q. Zhao, hep-ph/


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