Issues in hadron spectroscopy Stephen Lars Olsen Seoul

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Issues in hadron spectroscopy Stephen Lars Olsen Seoul National University 2011 International Workshop on

Issues in hadron spectroscopy Stephen Lars Olsen Seoul National University 2011 International Workshop on Nuclear, Particle and Astrophysics High-1, Korea, February 7 -10, 2011

Standard Model QCD Electroweak qj qj’ as~10 -1 qi QED gij eight “gluons” GF~10

Standard Model QCD Electroweak qj qj’ as~10 -1 qi QED gij eight “gluons” GF~10 -5 W±, Z a. QED ~10 -2 g photon qi • Perturb. calcs. are unreliable • Perturbative calculations are very reliable • Theoretically poorly understood • Theoretically well defined • Experimental tests minimal • Experimentally well tested

QCD diagrams for gg Higgs 2 nd order ~70% 1 st order +…

QCD diagrams for gg Higgs 2 nd order ~70% 1 st order +…

QCD calculations are difficult ● N=6 → 10860 Feynman diagrams ● N=7 → 168

QCD calculations are difficult ● N=6 → 10860 Feynman diagrams ● N=7 → 168 925 Feynman diagrams

Compare to QED process (g-2)m 1 st order 2 nd order ~1% 3 rdorder

Compare to QED process (g-2)m 1 st order 2 nd order ~1% 3 rdorder ~0. 01%

Ultimate theory limitation: hadrons Don’t calculate use e+e- hadrons &/or t hadrons n data

Ultimate theory limitation: hadrons Don’t calculate use e+e- hadrons &/or t hadrons n data + dispersion rel’ns had Vacuum polarization had No similar accessible process (ultimate limit on theory precision? ) Light-by-light scattering

Neutrino mass AMo. RE expt, etc: “Only way to measure neutrino mass” This is

Neutrino mass AMo. RE expt, etc: “Only way to measure neutrino mass” This is what we’ll measure (if we are incredibly skillful & fortunate) This is what we want Phase-space integral Nuclear matrix element Now there is no way to relate to <mn>2 from 1 st principles.

Quark model for hadrons (pre-QCD)

Quark model for hadrons (pre-QCD)

Original Quark Model 1964 The model was proposed independently by Gell-Mann and Zweig Three

Original Quark Model 1964 The model was proposed independently by Gell-Mann and Zweig Three fundamental building blocks 1960’s (p, n, l) Þ 1970’s (u, d, s) mesons are bound states of a of quark and anti-quark: Can make up "wave functions" by combining quarks: baryons are bound state of 3 quarks: proton = (uud), neutron = (udd), L= (uds) anti-baryons are bound states of 3 anti-quarks: Λ= (uds) 9

Make mesons from quark-antiquark __ uss _ ds d _ du_ _ sd _

Make mesons from quark-antiquark __ uss _ ds d _ du_ _ sd _ dd _ uu u ss s u __ d ud _ su _

Mesons come in octets JP=0498 JP=1 - 494 892 896 K*+ K*0 135 548

Mesons come in octets JP=0498 JP=1 - 494 892 896 K*+ K*0 135 548 139 776 783 r- r 0 w 776 r+ 776 f 958 1020 494 K*- 498 892 (p+, p 0, p-)=lightest _ K*0 896 (r+, r 0, r-)=lightest nr=0 S w av e

Construct baryon octets and decuplets Fom combinations of three uds triplets duu uuu d

Construct baryon octets and decuplets Fom combinations of three uds triplets duu uuu d d u u u d s uus s s HW: Finish the procedure

Answer: 8 -tet 10 -plet dud ddd sdd uud sud sud ssd ssu sss

Answer: 8 -tet 10 -plet dud ddd sdd uud sud sud ssd ssu sss uud suusuu

Baryons come in octets & decuplets 939 938 M=1232 Me. V 1115 1189 M=1385

Baryons come in octets & decuplets 939 938 M=1232 Me. V 1115 1189 M=1385 Me. V 1197 1192 M=1533 Me. V 1315 1321 M=1672 Me. V JP=1/2+ es all S av -w JP=3/2+ all nr=0 S all s ve a -w all nr=0 14

Problems with the quark model: • Individual quarks are not seen y b ”

Problems with the quark model: • Individual quarks are not seen y b ” D C Q • why only qqq and qq combinations? “F d e x i • violation of spin-statistics theorem?

st 1 principle QCD bound state calculations are impossible. Hadron (& nuclear) physics processes

st 1 principle QCD bound state calculations are impossible. Hadron (& nuclear) physics processes occur here Pentaquark? At these distance scales, as≈0. 5 this is a minimal diagram; no penalty for adding any number of additional gluons

Is it hopeless?

Is it hopeless?

no In principle, Lattice QCD can do it all But computing requirements are enormous

no In principle, Lattice QCD can do it all But computing requirements are enormous Blue. Gene/L Supercomputer Currently available supercomputers are only able to solve simple problems & even these require approximation techniques Guidance (& encouragement) from experiments is critical

QCD-inspired “new” spectroscopies - from the symmetry structure of theory Pentaquarks: e. g. an

QCD-inspired “new” spectroscopies - from the symmetry structure of theory Pentaquarks: e. g. an S=+1 baryon u d_ u d s dibaryons: tightly bound 6 -quark state (only the anti-s quark has S=+1) Glueballs: gluon-gluon color singlet states _ Tetraquark mesons _ qq-gluon u _c c u hybrid mesons c _ c s ud u ds not a nuclear state

Pentaquarks & the H-dibaryon

Pentaquarks & the H-dibaryon

quark antiquark? du dd d u s du ud d = s _ 3

quark antiquark? du dd d u s du ud d = s _ 3 3 = 6 3 _ 3 uu ds sd us su s diquark antitriplet attractive us = dd ud sd 6 repulsive uu su diquark antisextet ss ss

Pentaquarks? Exotics D. Diakonov, V. Petrov, and M. Polyakov, Z. Phys. A 359 (1997)

Pentaquarks? Exotics D. Diakonov, V. Petrov, and M. Polyakov, Z. Phys. A 359 (1997) 305. __ R. Jaffe & F. Wilczek PRL 91, 232003 (2003) du ds _ 3 antitriplet du _ 3 us ds us antitriplet N*(1440)? _ s _ u _ 3 10 N 0 S- = _ u antitriplet -- S 0 S+ 0 ---- S=-1 + - S=-2 N 0 S- N+ S 0 L L (1405)? See also: Y. S. Oh & H. C. Kim PRD 70, 094022 (2004) ---- S=0 N+ - _ 8 ----- S=+1 Q+ 0 0 ---- S=0 S+ -- S=-1 ------ S=-2 Prediction: M( - -) ≈ 1750~1850 Me. V - - p - | p - L 0

Q+ Pentaquark at Spring-8? Q+ decay modes: Q+ photo-production • Q + K +

Q+ Pentaquark at Spring-8? Q+ decay modes: Q+ photo-production • Q + K + n • need to deal with the neutron • Q + K 0 p • cannot tag the strangeness K+ Q+ need a neutron target (1 st experiment used 12 C tgt) n u+2/3 s+1//3 -1/3 d u+2/3 d-1/3 S=+1

Results CLAS-D (2005) Q+ K + n ? ? ? ? Width consistent with

Results CLAS-D (2005) Q+ K + n ? ? ? ? Width consistent with (11 Me. V) resolution T. Nakano et al (LEPS) PRC 79, 025210 (2009) B. Mc. Kinnon et al (CLAS) PRL 96 212001 (2006)

 - - in NA 49 Expt at CERN? L & signals are very

- - in NA 49 Expt at CERN? L & signals are very clean -p- + -p+ + _ _ + p + +p- M( p)5 = 1862± 2 Me. V G 5<18 Me. V S = 4. 2 s

No sign of X- - in CDF 5 X*(1530) X-p+ No peaks around M(Xp)

No sign of X- - in CDF 5 X*(1530) X-p+ No peaks around M(Xp) = 1860 Me. V/c 2 for X-p+ and X-p-

Pentaquark status “Seen” in many other experiments but not seen in just as many

Pentaquark status “Seen” in many other experiments but not seen in just as many others Belle BES Ba. Bar CDF High interest: 1 st pentaquark paper has ~820 citations

Positive pentaquark sightings since 2003

Positive pentaquark sightings since 2003

Negative pentaquark sightings since 2003

Negative pentaquark sightings since 2003

“The story of pentaquark shows how poorly we understand QCD” – F. Wilczek, 2005

“The story of pentaquark shows how poorly we understand QCD” – F. Wilczek, 2005

Pentaquarks in a gluon-rich environment less complicated than: (1 S) - - + X

Pentaquarks in a gluon-rich environment less complicated than: (1 S) - - + X (1 S) anti-deuteron + X p n d d _ s u b (1 S) s d b (1 S) b b X X ARGUS: Bf( (1 S) anti-deuteron + X)=3 x 10 -5 an appropriate comparison process A limit on Bf( (1 S) - - + X) below 10 -5 would be “compelling evidence” that Pentaquarks do not exist. Belle data: ~108 (1 S) decays 10 -5 Bf ~1000 produced 10% effic ~100 detected

H dibaryon? d u d s _ 3 d u u s antitriplet _

H dibaryon? d u d s _ 3 d u u s antitriplet _ 3 d s u s antitriplet d u s s u d R. L. Jaffee, PRL 38, 195 (1977): S=-2 di-hyperon with M<2 ML

H dibaryon decay modes MH(Me. V) H - p strong decay (probably wide) 12

H dibaryon decay modes MH(Me. V) H - p strong decay (probably wide) 12 C(K-, K+LLX) M + M N (2260 Me. V) C. J. Yoon et al (KEK-PS E 522) PRC 75, 022201 (2007) H LL strong decay 2 ML (2223 Me. V) H L n ML + Mn (2055 Me. V) weak decay most inter esti ng H n n weak decay

What mass is expected? LQCD long-lived ct > 3 cm!! • • 2010

What mass is expected? LQCD long-lived ct > 3 cm!! • • 2010

The “Nagara” LL 6 He event 6 LLHe 5 He L H. Takahashi et

The “Nagara” LL 6 He event 6 LLHe 5 He L H. Takahashi et al, PRL 87, 215502 (1977): MH > 2 ML-7. 7 Me. V

Recent Lattice QCD calculations MH= 2 ML – 16. 1 ± 2. 1 ±

Recent Lattice QCD calculations MH= 2 ML – 16. 1 ± 2. 1 ± 4. 6 Me. V MH= 2 ML – “(30~40) Me. V

Production via gluons X Need to: produce 6 quark-antiquark pairs (including two ss quark

Production via gluons X Need to: produce 6 quark-antiquark pairs (including two ss quark pairs) very close in phase space d u s s u d Is this likely? ? ?

Anti-deuteron production Similar process!! d p n

Anti-deuteron production Similar process!! d p n

Experimental signatures MH(Me. V) H ~2 Ge. V shower that doesn’t look like a

Experimental signatures MH(Me. V) H ~2 Ge. V shower that doesn’t look like a g-ray -p M + Mp (2260 Me. V) x H L n L p n p+ H LL 2 ML (2223 Me. V) H Belle Cs. I detector weak decay 2215 Me. V Ruled out by Nagara? H L n is hard, but H L n is possible in Belle advantage of gluon production is equal rates for H and H

Pentaquark & H-dibaryon searches via gluonic systems with sensitivites below the d production rate

Pentaquark & H-dibaryon searches via gluonic systems with sensitivites below the d production rate should be conclusive.

The “XYZ” exotic meson candidates

The “XYZ” exotic meson candidates

Strategy: Search for a meson that decays to a final state containing a c

Strategy: Search for a meson that decays to a final state containing a c and c quark, If it is a standard qq meson, it has to occupy one of the unfilled states indicated above. If not, it is exotic. predicted measured

cc production at B factories

cc production at B factories

The X(3872) Study p+p-J/ produced in B K p+p- J/ decays ? ?

The X(3872) Study p+p-J/ produced in B K p+p- J/ decays ? ?

The X(3872) B K p+p-J/ ’ p+p-J/ X(3872) p+p-J/ S. K. Choi et al

The X(3872) B K p+p-J/ ’ p+p-J/ X(3872) p+p-J/ S. K. Choi et al PRL 91, 262001 M(pp. J/ ) – M(J/ )

Its existence is well established seen in 4 experiments CDF 9. 4 s 11.

Its existence is well established seen in 4 experiments CDF 9. 4 s 11. 6 s X(3872) D 0 Ba. Bar X(3872)

X 3872 JPC values Angular correlation analysis by CDF: §Fit to M(pp) favors r

X 3872 JPC values Angular correlation analysis by CDF: §Fit to M(pp) favors r p+phep-ex/0505038 JPC = 1++ CDF: PRL 98 132002 PRL 96, 102002(2006) JPC = 1++ or 2 -+

Ba. Bar: X 3872 g. J/ & g ’ B+ K+g. J/ 3. 6

Ba. Bar: X 3872 g. J/ & g ’ B+ K+g. J/ 3. 6 s G(X g. J/ ) 1/10 G(X p+p-J/ ) 1++ g J/ or g ’ Allowed E 1 2 -+ g. J/ or g ’ Suppressed E 2 B+ K+g ’ M(g. J/ ) JPC = 1++ favored over 2 -+ 3. 5 s PRL 102, 132001 M(g ’)

can it be the ++ 1 cc state? 1++ cc 1’ (the only charmonium

can it be the ++ 1 cc state? 1++ cc 1’ (the only charmonium possibility) M=3872 Me. V is low, cc 1’ p+p- J/ is 3872 Me. V g p +p - (Isospin violating) a forbidden decay cc 1’ g J/ is an allowed E 1 transition; should be stronger than p+p-J/ , not 10 x weaker. If it is not the c’c 1, what is it?

X(3872) looks like a molecule 0 0 D* D

X(3872) looks like a molecule 0 0 D* D

CDF X(3872) p+p- J/ Mass recent results ~6000 events! ar. Xiv: 0906. 5218 MX

CDF X(3872) p+p- J/ Mass recent results ~6000 events! ar. Xiv: 0906. 5218 MX = 3871. 61 ± 0. 16 ± 0. 19 Me. V

M X(3872) ≈ MD 0 +MD*0 <MX>= 3871. 46 ± 0. 19 Me. V

M X(3872) ≈ MD 0 +MD*0 <MX>= 3871. 46 ± 0. 19 Me. V new Belle meas. new CDF meas. MD 0 + MD*0 3871. 8± 0. 4 Me. V dm = -0. 35 ± 0. 41 Me. V

X 3872 couples to D*0 D 0 Belle X 3872 D 0 D*0 &

X 3872 couples to D*0 D 0 Belle X 3872 D 0 D*0 & ar. Xiv: 08100358 D*→Dγ 414 fb-1 D 0 D 0 p 0 D*→D 0π0 605 fb-1 Ba. Bar X 3872 D 0 D*0

Eric Braaten ar. Xiv: 0907. 3167 ≥ 6 fer mis !!

Eric Braaten ar. Xiv: 0907. 3167 ≥ 6 fer mis !!

X(3872)-J/ relative sizes drms(X 3872) ≈ 6 fm drms(J/ ) ≈ 0. 4 fm

X(3872)-J/ relative sizes drms(X 3872) ≈ 6 fm drms(J/ ) ≈ 0. 4 fm Vol(J/ ) Vol(X 3872) Size similar to 11 Li & 19 C “halo” nuclei studied by Prof. Satoh ≈ 10 -3 _ • Overlap of the cc necessary to form the J/ in X p+p-J/ decays is rare _ • Probability forming such a fragile object in H. E. pp collisions is small -- ar. Xiv 0906. 0882: s. CDF(meas)>3. 1± 0. 7 nb vs stheory(molecule)<0. 11 nb

_ Produced like the ’ in pp collisions • Fraction from B decays –

_ Produced like the ’ in pp collisions • Fraction from B decays – Long-lived fraction y(2 S) : (drms ≈ 0. 4 fm) 28. 3 1. 0(stat. ) 0. 7(syst. ) % X(3872) : (drms ≈ 6 fm? ? ) 16. 1 4. 9(stat. ) 1. 0(syst. ) % X(3872) behaves similarly to y(2 S). X(3872) mostly prompt.

X(3872)=diquark-diantiquark ? Expect SU(3) multiplets Isospin partners X-= d S=-1 partners Xs-= s doublet

X(3872)=diquark-diantiquark ? Expect SU(3) multiplets Isospin partners X-= d S=-1 partners Xs-= s doublet of “X(3872)” states DM=8± 3 Me. V Maiani et al PRD 71, 014028

No multiplet partners seen Ba. Bar search for “X-(3872)” p-p 0 J/ PRD 71,

No multiplet partners seen Ba. Bar search for “X-(3872)” p-p 0 J/ PRD 71, 031501 B 0 B- X(3872)– M(J/ π–π0) Bf(B 0 K+X-)Bf(X- p-p 0 J/y) Bf(B- K+X 0)Bf(X- p-p-J/y) X(3872)– M(J/ π–π0) < 0. 4 (expect 2)

Many (>10) other states poorly consistent with quark model observed last 6 years by

Many (>10) other states poorly consistent with quark model observed last 6 years by B-factories

What are hadrons made of? • 40 years after Gell-Mann’s quarks, we still don’t

What are hadrons made of? • 40 years after Gell-Mann’s quarks, we still don’t know 2 B ES 3/B e lle DA PA N FA IR/ Possibilities Som en re ew to a b s e le trut n lex o arn h dr omp a ed c H o to – expected non-qq mesons &/or non-qqq baryons not seen – non-qq meson candidates that are seen defy any comprehensive theoretical understanding.

Z(4430) and Z 1(4050) & Z 2(4250) Smoking guns for charmed exotics: u c

Z(4430) and Z 1(4050) & Z 2(4250) Smoking guns for charmed exotics: u c d c

B K p ’ (in Belle) M 2(p+ ’) ? ? K*(1430) K+p-? K*(890)

B K p ’ (in Belle) M 2(p+ ’) ? ? K*(1430) K+p-? K*(890) K+p- M 2(K+p-)

The Z(4430)± p± ’ peak B K p+ ’ evts near M(p ’) 4430

The Z(4430)± p± ’ peak B K p+ ’ evts near M(p ’) 4430 Me. V M 2(p± ’) Ge. V 2 Z(4430) M(p± ’) Ge. V M (Kp’) Ge. V M 2(Kp’) Ge. V 2 “K* Veto”

Could the Z(4430) be due to a reflection from the Kp channel?

Could the Z(4430) be due to a reflection from the Kp channel?

Cos qp vs M 2(p ’) qp p ’ K +1. 0 22 Ge.

Cos qp vs M 2(p ’) qp p ’ K +1. 0 22 Ge. V 2 (4. 43)2 Ge. V 2 0. 25 cosqp M 2(p ’) 16 Ge. V 2 M (p ’) & cosqp are tightly correlated; a peak in cosqp peak in M(p ’) -1. 0

S- P- & D-waves cannot make a peak (+ nothing else) at cosqp≈0. 25

S- P- & D-waves cannot make a peak (+ nothing else) at cosqp≈0. 25 not without introducing other, even more dramatic features at other cosqp (i. e. , other Mp ’) values.

But…

But…

Ba. Bar doesn’t see a significant Z(4430)+ “For the fit … equivalent to the

Ba. Bar doesn’t see a significant Z(4430)+ “For the fit … equivalent to the Belle analysis…we obtain mass & width values that are consistent with theirs, … but only ~1. 9 s from zero; fixing mass and width increases this to only ~3. 1 s. ” Belle PRL: (4. 1± 1. 0± 1. 4)x 10 -5

Reanalysis of Belle’s B Kp ’ data using Dalitz Plot techniques

Reanalysis of Belle’s B Kp ’ data using Dalitz Plot techniques

2 -body isobar model for Kp ’ Our default model B K* ’ k

2 -body isobar model for Kp ’ Our default model B K* ’ k ’ K 2* ’ K*(890) ’ KZ+ Kpy’ K*(1410) ’ K 0*(1430) ’ K 2*(1430) ’ K*(1680) ’ KZ+

Results with no + KZ term 2 1 12 3 4 5 C B

Results with no + KZ term 2 1 12 3 4 5 C B 3 A 4 A B 5 fit CL=0. 1% C 51

Results with a KZ+ term 1 3 2 4 1 2 3 4 5

Results with a KZ+ term 1 3 2 4 1 2 3 4 5 A C B C A 5 fit CL=36% B

Compare with PRL results K* veto applied With Z(4430) Signif: 6. 4 s Published

Compare with PRL results K* veto applied With Z(4430) Signif: 6. 4 s Published results Without Z(4430) Mass & significance similar, width & errors are larger Ba. Bar: Belle: No big contradiction -5 = (3. 2+1. 8+9. 6 0. 9 -1. 6 )x 10

Variations on a theme Z(4430)+ significance Others: Blatt f-f term 0 r=1. 6 fm

Variations on a theme Z(4430)+ significance Others: Blatt f-f term 0 r=1. 6 fm 4 fm; Z+ spin J=0 J=1; incl K* in the bkg fcn

The Z 1(4050)+ & Z 2(4250)+ p+cc 1 peaks R. Mizuk et al (Belle),

The Z 1(4050)+ & Z 2(4250)+ p+cc 1 peaks R. Mizuk et al (Belle), PRD 78, 072004 (2008)

Dalitz analysis of B 0 K-p+cc 1 DE Ge. V ? ? ? K

Dalitz analysis of B 0 K-p+cc 1 DE Ge. V ? ? ? K 3*(1780) K*(1680) K*(1400)’s M (J/ g) Ge. V K*(890) G

B Kpcc 1 Dalitz-plot analyses Default Model B K*cc 1 kcc 1 K 2*cc

B Kpcc 1 Dalitz-plot analyses Default Model B K*cc 1 kcc 1 K 2*cc 1 K*(890)cc 1 KZ+ Kpcc 1 K*(1410)cc 1 K 0*(1430)cc 1 K 2*(1430)cc 1 K*(1680)cc 1 K 3*(1780)cc 1 KZ+

Fit model: all low-lying K*’s (no Z+ state) a b c d g f

Fit model: all low-lying K*’s (no Z+ state) a b c d g f e a b e c d g f C. L. =3 10 -10

Fit model: all K*’s + one Z+ state a b c d g f

Fit model: all K*’s + one Z+ state a b c d g f e a b e c d g f C. L. =0. 1%

Are there two? ? ? ? a b c d ?

Are there two? ? ? ? a b c d ?

Fit model: all K*’s + two Z+ states a b c d g f

Fit model: all K*’s + two Z+ states a b c d g f e a b e c d g f C. L. =42%

Two Z-states give best fit Projection with K* veto

Two Z-states give best fit Projection with K* veto

XYZ Summary

XYZ Summary

What are hadrons made of? • 40 years after Gell-Mann’s prize, we still don’t

What are hadrons made of? • 40 years after Gell-Mann’s prize, we still don’t know 2 B ES 3/B e lle DA PA N FA IR/ Possibilities Som en re ew to a b s e le trut n lex o arn h dr omp a ed c H o to – expected non-qq mesons &/or non-qqq baryons not seen – non-qq meson candidates that are seen defy any comprehensive theoretical understanding.

Quantum Chromodynamics QED: scalar charge e a. QED single photon QED gauge transform +ie.

Quantum Chromodynamics QED: scalar charge e a. QED single photon QED gauge transform +ie. A 1 vector field (photon) QCD triplet charge: ej as Non-Abelian extension of QED ei er eb eg gij eight “gluons” QCD gauge transform + i a l i Gi eight 3 x 3 SU(3) matrices 8 vector fields (gluons)

Vacuum polarization QED vs QCD QED 2 nf 11 CA in QCD: CA=3, &

Vacuum polarization QED vs QCD QED 2 nf 11 CA in QCD: CA=3, & this dominates as increases with distance QCD

QED: photons have no charge coupling decreases at large distances QCD: gluons carry color

QED: photons have no charge coupling decreases at large distances QCD: gluons carry color charges gluons interact with each other coupling increases at large distances a Coupling strengths distance

Test QCD with 3 -jet events (& deep inelastic scattering) as gluon rate for

Test QCD with 3 -jet events (& deep inelastic scattering) as gluon rate for 3 -jet events should decrease with Ecm

“running” as Large distance short distance

“running” as Large distance short distance

The QCD particle spectrum hasn’t been computed Quark-binding into hadrons occurs here (Q≈mp≈140 Me.

The QCD particle spectrum hasn’t been computed Quark-binding into hadrons occurs here (Q≈mp≈140 Me. V) as (mp) ~ 0. 5 perturbation theory can’t be used Theorists make “QCD-motivated” models that must be tested by experiment

excited baryon octets? proton all S -wav es JP=1/2+ all nr=0 JP=1/2+ JP=1/2 -

excited baryon octets? proton all S -wav es JP=1/2+ all nr=0 JP=1/2+ JP=1/2 - e e on P- v wa all nr=0 e on all S-wave =1 nr 1/2 - 1/2 + N*(1535) N*(1440) L(1405) ? ? ? L(1620) S(1580) S(1660) (? ) ? ? ?

1 st sign? Scalar meson nonet JP=0+ ~800 980 ao- k 0 k+ 980

1 st sign? Scalar meson nonet JP=0+ ~800 980 ao- k 0 k+ 980 f 0 ~600 nr=0 ~800 p- k - ao 0 980 ~800 ao+ 980 s _ k 0 ~800 w av e (a+o, a 0 o, ao-) = heaviest! Ma 0 =980 Me. V ; 2 m. K =990 Me. V does the a 0 meson have the same quark content as KK, i. e. usus? _

diquark diantiquark nonet? JP=0+ __ du ds __ sd _ 3 us diquark antitriplet

diquark diantiquark nonet? JP=0+ __ du ds __ sd _ 3 us diquark antitriplet ~800 su 3 = 980 a- k 0 k+ 980 o ~600 __ du diantiquark-triplet _ 3 3 = 8 1 f 0 ~800 k - a 0 980 o ~800 a+ o s _ k 0 ~800 980

_ _ _ Is the f 0(980) a (uu+dd)ss state? KK threshold BES sees

_ _ _ Is the f 0(980) a (uu+dd)ss state? KK threshold BES sees an abrupt switch from f 0(980) pp to f 0(980) KK at threshold

The LEPS observation of Q+(1530)? Carbon target + K - K “n” g n

The LEPS observation of Q+(1530)? Carbon target + K - K “n” g n M(K+“n”) g + “n” K- K+ “n” Physical Review Letters, 91, 012002 (2003) (“n” = neutron inside Carbon nucleus)

LEPS follow-up Expt L (1520)= control Q+ ? (with a deuterium target) undetected

LEPS follow-up Expt L (1520)= control Q+ ? (with a deuterium target) undetected

Inferring the neutron’s 4 -mom They know the 4 -mom. of the n p

Inferring the neutron’s 4 -mom They know the 4 -mom. of the n p system q e np ram f t s re But they don’t know q They chose q to be the angle that minimizes the spectator’s cm momentum

Shows up in all data subsamples

Shows up in all data subsamples

Lots of interest in the X(3872) line shape C. Hanhart et al ar. Xiv:

Lots of interest in the X(3872) line shape C. Hanhart et al ar. Xiv: 1002. 4097 also E. Braaten et al PRD 81 014019 Line shape and very precise mass measurement only possible at FAIR