1. Quarkonium experimental overview I France-Asia Particle Physics School, Les Houches, FRANCE October 11-12, 2011 Stephen Lars Olsen Seoul National University

2. Outline ’’ J/  ”” Lecture 1: Bound charmonium & bottomonium states and their properties  (1S)  (4S)

3. Outline X(3872) Lecture 2: Non-quarkonium, quarkonium-like states and the future Y(3940) Y(4260) Z b (10610) Z b (10650)

4. Lecture 1 Bound charmonium & bottomonium states and their properties

5. 5 Constituent Quark Model 1964 The model was proposed independently by Gell-Mann and Zweig Three fundamental building blocks 1960’s (p,n, )  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),  = (uds) anti-baryons are bound states of 3 anti-quarks: Λ = (uds)

6. Make mesons from quark-antiquark d u s s _ _ d _ _ u _ us _ ud _ uu _ ds _ du _ sd _ su _ ss _ dd _ Y IZIZ _ YY=“hypercharge” = S+B +1/3 -2/3 -1/2 +1/2

7. Ground state mesons (today) J P =0 - J P =1 - K* 0 K* + K* - K* 0 _ 00 -- ++   139 135 548 958 498 494 896 892 776 783 1020 S-wave n r =0 S-wave n r =0 (  +,  0,  - )=lightest (  +,  0,  - )=lightest

8. HW: d u s d u s d u s uuu duu Construct baryon octet and decuplet combinations of three uds triplets Finish the procedure uus

9. Answer  2(8-tet)s + 10-plet  singlet uud dud sdd ddd dud sdd sud suu ssd ssu sss sud

10. 10 Ground state Baryons M=1672 MeV M=1533 MeV M=1385 MeV M=1232 MeV 1192 1115 1189 938 1197 939 1321 1315 J P =1/2 + J P =3/2 + all S-waves all n r =0

11. Are quarks real objects? or just mathematical mnemonics? 기억하는 Are quarks actually real objects?" Gell-Mann asked. "My experimental friends are making a search for them in all sorts of places -- in high-energy cosmic ray reactions and elsewhere. A quark, being fractionally charged, cannot decay into anything but a fractionally charged object because of the conservation law of electric charge. Finally, you get to the lowest state that is fractionally charged, and it can't decay. So if real quarks exist, there is an absolutely stable quark. Therefore, if any were ever made, some are lying around the earth." But since no one has yet found a quark, Gell-Mann concluded that we must face the likelihood that quarks are not real. Gell-Mann Nobel Prize 1969 助记符

12. A prediction of the quark model:

13. Mark I detector At SLAC’s “SPEAR” e + e - collider tracking chamber muon identifier ~3GeV e+e+ e-e-

14. R data in June 1974 Compilation by: L. Paoluzi Acta Physica Polonica B5, 829 (1974) 2/3 Not even close to 2/3 Big data fluctuations around 3.0 GeV E cm e+e+ e-e- hadrons R

15. after a fine energy scan near 3 GeV: 10  J.J. Aubert et al., PRL 33, 1404 (1974) J.E. Augustine et al., PRL 33, 1406 (1974) J Also seen in pN  e + e - X at Brookhaven A huge, narrow peak near 3.1 GeV R=2.2 >>2/3 The “J /  ” meson M(e + e - )

16. Another peak near 3.69 GeV G.S. Abrams et al., PRL 33, 1453 (1974) ’’  About 2 weeks later

17. Why J/  ?  ’   +  - J/   e + e - Mark-I detector Event in Mark I Group leader of the Brookhaven expt Samuel C.C. Ting Chinese character for Ting:

18. Interpretation of J/  and  ’ charmed quark  q= +2/3 partner of the s-quark cccc n r =0 M=3.097 GeV n r =1 M=3.686 GeV S-wave charmed-quark anticharmed-quark mesons A q=+2/3 rds partner of the s quark had been suggested by many theorists before 1974after 1974

19. Charmonium r mesons formed from c- and c-quarks c-quarks are heavy: m c ~ 1.5 GeV  2m p velocities small: v/c~1/4 non-relativistic, undergraduate-level QM applies cc

20. QM of cc mesons cc r What is V(r) ?? “derive” from QCD

21. “Cornell” potential ~0.1 fm linear “confining” long distance component slope~1GeV/fm 1/r “coulombic” short distance component c c r V(r) 2 parameters: slope & intercept r

22. Charmonium (cc) Positronium (e + e - ) _ ’’ J/ 

23. The “ABC’s” of charmonium mesons S=1  triplet of state S=0  singlet Parity (x,y,z) ↔ (-x,-y,-z) C-Parity quark ↔ antiquark J PC quantum numbers X e+e+ e-e- J/  (  ’ ) photon: J PC = 1 - - J/  (  ’ ): J PC = 1 - - c cc

24. n (2S+1) L J n=radial quant. nmbr S= spin (0 or 1) L= S, P, D, F, … J= total ang. mom. J/  = 1 3 S 1  ’ = 2 3 S 1 ABC’s part II spectroscopic notation c cc  c = 1 1 S 0  c = 2 1 S 0 ’ 0, 1, 2, 3, …

25. ABC’s part III “wave function at the origin” c c e+e+ e-e-  In J/  decay, the c and c quarks have to annihilate each other _ This only can happen when they are very near each other: Many J/  processes are  |  (0)| 2, the “wave function at the origin,” or, in the case of states with  (0)=0, derivatives of  (0), which are usually small. n=1 n=2 n=3 S-wave P-wave S-wave P-wave D-wave

26. Immediate questions: Can the other meson states be found? Why are the J/  and  ’ so narrow?

27. Finding other states J/  = 1 3 S 1  ’ = 2 3 S 1 These states have been identified What about these? c cc c cc  c2 = 1 3 P 2  c0 = 1 3 P 0  c1 = 1 3 P 1

28. The Crystal Ball Detector

29. E-dipole  transitions to 1 3 P 0,1,2 e-e- ’’ J  24. E. Eichten et al., PRL 34, 369(1975) QM textbook formula: 24. 29. 26. 313. 239. 114. ’’ e+e+ e-e-

30. Crystal ball results ’’ e+e+ e-e- ’’ J  EE ’ X’ X “smoking gun” evidence that quarks are real spin=1/2 objects Crystal Ball expt: Phys.Rev.D34:711,1986.

31.  ’   c0 radiative transition BESII PRD 70, 092004 (2004) Expect 1+cos 2 

32. Discovery of the P-wave states (  c0,1,2 ) convinced everyone quarks were real e-e- ’’ J  Crystal Ball expt: Phys.Rev.D34:711,1986. EE

33. Immediate questions: Can the other meson states be found? Why are the J/  and  ’ so narrow? Done!

34. Problems with the quark model: Individual quarks are not seen why only qqq and qq combinations? violation of spin-statistics theorem?

35.  s -1/3 three s-quarks in the same quantum state Das ist verboten!!

36. The strong interaction “charge” of each quark comes in 3 different varieties Y. Nambu M.-Y. Han s -1/3 the 3 s -1/3 quarks in the  - have different strong charges & evade Pauli -- 1 2 3

37. Attractive configurations  ijk e i e j e k i ≠ j ≠ k  ij e i ejej same as the rules for combining colors to get white : add 3 primary colors -or- add color+complementary colo r antiquarks:  anticolor charges quarks: e i e j e k  color charges ejej eiei ekek i k j i j Baryons: Mesons:  ijk e i e j e k  ij e i ejej

38. Quantum Chromodynamics eiei ejej g ij single photon eight “gluons”  QED ss Non-Abelian extension of QED    + i e A QED gauge transform 1 vector field (photon) QED: scalar charge e    + i  i G i QCD gauge transform eight 3x3 SU(3) matrices 8 vector fields (gluons) QCD triplet charge: erebegerebeg

39. Vacuum polarization QED vs QCD 2n f 11C A in QCD: C A =3, & this dominates  s increases with distance QED QCDQCD

40. 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  Coupling strengths distance

41. Test QCD with 3-jet events (& deep inelastic scattering) rate for 3-jet events should decrease with E cm gluon ss

42. “running”  s Large distance short distance M J/   s ~1/4

43. Color explains the discrepancy in R Each quark has 3 colors & color

44. 10 J  R=2.2 >>2/3

45. why are the J/  and  ’ so narrow? 234 E cm

46. How does the J/  (  ’) decay? c g ij ss c c ss c ss g kl c g ij ss c g kl ss ss g mn violates color symmetry violates C parity Lowest-order allowed QCD process:  suppressed by  s 3 This is called “OZI”* suppression *Okubo-Zweig-Iizuka C=-

47. How wide is the J/  (&  ’)? ’’ J/  The observed widths of these peaks are due entirely to experimental resolution, which is typically a few MeV

48. Determining the J/  (&  ’) widths  ee XX X cross section for e + e -  J/   X X=hadrons X=  +  - X=e + e - Mark-I PRL 34, 1357 (1975) J/ ’’  tot 93 ± 2 keV309 ± 9 keV  ee 5.55 ± 0.14 keV5.1 ± 0.5 keV 2009 values e+e+ e-e- 4 eqns, 4 unknowns

49. e + e -  hadrons at higher E cm : a 3 rd peak: the  ” (  (3770)) ”” 2009 values LGW PRL 39, 526 (1977)  tot ~150x bigger  ee ~20x smaller ”” J/ ’’ ””  tot 93 keV209 keV27.3+1.0 MeV  ee 5.55 keV5.1 keV0.26+0.02 keV ’’

50. Why is  tot (  ”) much bigger? c c New decay channel is available:  ”  DD D D c q q c q (=u or d)  D 0 or D +  D 0 or D - ”” 2m D + =3739 MeV 2m D 0 =3729 MeV “charmed” mesons 2m D “open charm” threshold (M  ’ =3686 MeV ) (M  ” =3775 MeV ) no “OZI” suppression “Fall apart” Decay modes

51. does  ” fit in the cc spectrum? must be J PC = 1 - - here? or here?  (1D) 2m D _

52.  ee (  ”) considerations c c e+e+ e-e-  J/ ’’  ”(S-wave)  ”(D-wave)  ee (Theory) 12.135.033.50.056  ee (expt) 5.55 ± 0.145.1 ± 0.50.26 ± 0.02 all in keV  ee = too small for the  ” to be the  (3S) state & too big for it to be the  (1D) S-waveD-wave

53.  ’ and  ” = 2 3 S 1 – 1 3 D 1 mixtures  (1D) mixing “preferred” value This mixing was predicted by Eichten et al, PRL 34, 369 (1975) -- before the  ” was discovered --

54. Finding other charmonium mesons ”” Look for the  c via  ’   c or J/    c ~700MeV ~100MeV

55. Xtal-ball: J/  ’    c,  c  inclusive M  c =2978 ± 9 MeV  <20 MeV Xtal-Ball PRL 45, 1150 (1980) ???  ’   + anythingJ/    + anything

56. Mark II  ’   c,  c  exclusive good  ’s poor  ’s bkg subtracted M  c =2980 ± 8 MeV  <40 MeV Mark II PRL 45, 1146 (1980)

57. The  c in 2010 (30 years later) M &  still not well measured! However, see recent papers by BES III, Belle & BaBar

58. Search for the  c ’ ””

59.  ’    c ’ in the Crystal Ball? 100 MeV1000 MeV Xtal-Ball PRL 48, 70 (1982) M  c =3592 ± 5 MeV  <8 MeV Never Confirmed ???

60. M=3592 MeV  c ’ not seen elsewhere pp   c ’   (@ Fermilab) _ E835 PRD 64, 052003 (2001)    c ’  hadron (@ LEP) DELPHI PL B441, 479 (1998)

61. The Belle experiment at KEK ~10GeV e+e+ e-e-

62. Belle in 2002 (20 yrs later) cccc _   c (  c ’ ?? )  K S K +  - M(K S K +  - ) cc c’c’ sqsq _ KK M  c =3654 ± 10 MeV  <55 MeV Belle PRL 89, 102001 (2002) B meson “invariant mass”

63. Confirmed by other measurements PDG 2009 χ c0 χ c2 ηc’ηc’ ηc’ηc’ ηc’ηc’ Belle:   3(  +  - )   K + K - 2(  +  - )   K S K +  +  -  - M(3(  +  - )) M( K + K - 2(  +  - ))  K S K +  +  -  - ) Belle:  e + e -  J/  + X M(X) ηc’ηc’ Belle PRL 98, 082001 (2007) Belle: 2010 (preliminary) 3592 MeV

64. Search for the h c ””

65. Strategy J PC (  ’ ):= 1 - - J PC (h c ) = 1 +-   ’   h c not allowed ’’ hchc cc  ’   0 h c allowed but suppressed expected branching fraction ≈ 10 -3 preferred h c decay mode is h c   c expected branching fraction ≈ 0.4 Expected mass = “center-of-gravity” of M(  c0,1,2 ) =[M(  c0 ) + 3 M(  c1 ) +5 M(  c2 )]/9 = 3.525 MeV

66. CLEO detector at Cornell Univ

67. h c : CLEO 2005 (exclusive) clean h c   c signal Exclusive analysis:

68. Recoil mass (or “Missing mass”} ’’ ’’ 00 hchc undetected detected   4-momentum conservation In the cm: recoiling or “missing”

69. Recoil mass (or “missing mass”

70. h c : CLEO 2005 (semi-inclusive) h c   c signal Inclusive analysis: undetected detect the  0   & the  from h c   c Mass recoiling from the  0 CLEO PRL 95,102003 (2005)

71. BESIII experiment at IHEP(Beijing)

72. h c : BES III 2010 (fully inclusive) Semi-inclusive:  ’   0 h c    c Detect:  0 &  Measures: Bf(  ’   0 h c )xBf(h c   c ) Measures: Bf(  ’   0 h c ) Fully inclusive:  ’   0 h c    c Detect:  0 only BES III PRL 104,132002 (2010)

73. h c : BES III results results: Bf(  ’   0 h c ) = (8.4 ± 1.3)x10 -4 Bf(h c   c ) = (54.3 ± 6.7)% M(h c ) = 3525.4 ± 0.22 MeV  (h c ) = 0.73 ± 0.53 (< 1.44) MeV agree with theory YP Kuang PRD 65 094024 M cog (  c0,1,2 )=3525.3 MeV BES III PRL 104,132002 (2010)

74. All states below “open charm” threshold are identified ”” 2m D 0

75. J PC = 1 - - states produce peaks in R had ””   These are wide because decays to charmed mesons are allowed BES II PL B660, 315 (2008)

76. All 1 - - states below 4500 MeV are identified ”” 2m D 0      

77.  c2 discovered by Belle ‘    c2  DD ‘ _ M(DD) _ |cos  | results: M(  c2 ) = 3929 ± 5 MeV  (  c2 ) = 29 ± 10 MeV “two-photon” collisions

78. Charmonium spectrum today ”” 2m D 0      ’’ c2 Masses in pretty good agreement with theoretical expectations -- biggest discrepancies ~ 50 MeV --

79.  Transitions  e-e- Th. Expt 24 27 ± 4 29 27 ± 3 26 27 ± 3 313 426 ± 51 239 291 ± 48 114 110 + 19 E1 transitions  0 M1 transitions (  (keV) ) J/     c 2.4 1.6 ± 0.4  ’    c 4.6 1.1 ± 0.2 Th. Expt

80. Hadronic transitions   0  ’  J/  +hadrons ’’  0 J/   exp (keV)  ‘      J/  88 ± 7  ’    J  9 ± 1   ’   0 J/  0.4 ± 0.1 Ispin violation:  ’   0 J/   ’   J/  ~1/200

81. Predictions & measurements for the  ”  e-e-  0    exp (keV) th. Expt  ”      J/  ~80 55 ± 15  ”     c1 77 70 ± 17   ”   c0  172 ± 30

82. Bottomonium: history repeats itself 3 narrow states near 10 GeV Plus broad states at higher masses

83. Same potential works ~0.1 fm linear “confining” long distance component slope~1GeV/fm 1/r “coulombic” short distance component b b r V(r) 2 parameters: slope & intercept r

84. Bottomonium spectrum 2M B = 10.56 GeV More states below “open bottom” threshold

85. “Fall apart” decays to “B” mesons b b B B b q q b q (=u or d) B 0 or B - B 0 or B +  (4S) 2m B =10.56 GeV 2m B “open bottom” threshold (M  ’(3S) =10.36 GeV ) no “OZI” suppression (M  ’(4S) =10.58 GeV )

86. Bottomonium spectrum 2011 2M B = 10.56 MeV Most of the states below “open bottom” threshold have been identified established recently discovered still not discovered

87. Summary (lecture 1) The quarkonium spectra are strong evidence that hadrons are composed of spin=1/2 constituent particles All of the charmonium states below the M=2m D “open charm” threshold have been found - most of the bottomonium states below M=2m B have been identified Above the threshold, most of the 1 - - states, but only one of the others (the  c2 ’) have been discovered. The masses of the assigned states match theory predictions - variations are less than ~50 MeV Transitions between quarkonium states are in reasonably good agreement with theoretical expectations

88. General comments The charmed and bottom “quarkonium systems” are relatively simple and reasonably well understood. The “hydrogen atoms” of QCD. Let’s try to use them to search for new and unpredicted phenomena. The subject of lecture 2

89. Thank You 謝謝 Merci どもぅ ありがとぅ 감사합니다

90. Quarkonium experimental overview I Stephen Lars Olsen Seoul National University France-Asia Particle Physics School, Les Houches, FRANCE October 11-12, 2011 ++ -- ++ -- -- ++ e-e- e+e+  ’   +  - J/    +  - (e + e - ) in the BESIII detector

91. outline Lecture1: The bound charmonium & bottomonium states and their properties Lecture 2: The non-quarkonium, quarkonium-like states & the future