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Quarkonium experimental overview II

Quarkonium experimental overview II. Stephen Lars Olsen Seoul National University. France-Asia Particle Physics School, Les Houches, FRANCE October 11-12, 2011. X(3872). Z b (10610). Y(3940). Y(4260). Outline. Z b (10650). Lecture 2: Non-quarkonium, quarkonium-like

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Quarkonium experimental overview II

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

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

  3. 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=2mD “open charm” • threshold have been found • -most of the bottomonium states below M=2mB have been identified • Above the threshold, most of the 1- - states, but only one of the • others (the cc2’) 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

  4. Charmonium spectrum today Masses in pretty good agreement with theoretical expectations -- biggest discrepancies ~ 50 MeV -- y(4415) y(4150) y(4040) c’ c2 y” 2mD0

  5. g Transitions M1 transitions (G(keV)) J/yghc2.4 1.6 ± 0.4 y’ ghc4.6 1.1 ± 0.2 Th. Expt pp,h,p0 g e- E1 transitions Th. Expt 24 27 ± 4 29 27 ± 3 26 27 ± 3 313 426 ± 51 239 291 ± 48 114 110 + 19

  6. Hadronic transitions y’  J/y +hadrons • Gexp(keV) • y‘p+p-J/y88 ± 7 • y’ hJ/y 9 ± 1 • y’ p0J/y 0.4±0.1 pp, h, p0 pp,h,p0 g y’ J/y Ispin violation: y’p0J/y y’ppJ/y ~1/200

  7. Bottomonium spectrum today established recently discovered still not discovered 2MB = 10.56 MeV

  8. Constituent Quark Model Λ= (uds) Mesons are quark-antiquark pairs Baryons are quark-quark-quark thriplets Fabulously successful Quarks are probably the most well known particle physics quantity among the general public 8

  9. Why no other color-singlet combinations? Pentaquark: H-diBaryon Glueball Tetraquark mesons qq-gluon hybrid mesons Other possible “white” combinations of quarks & gluons: u d u d s _ u tightly bound 6-quark state S=+1 Baryon d s u s d Color-singlet multi- gluon bound state D0 _ c _ u loosely bound meson-antimeson “molecule” c tightly bound diquark-diantiquark u _ p _ u c _ _ u _ D*0 c _ _ c c

  10. predicted measured One 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. unassigned _ _

  11. p+p-/Jy systems produced in B decay Polarized along flight direction in B rest frame y’, X? EB=Ecm/2 B0KSy’; y’p+p-J/yare very useful decays for CP violation studies

  12. M(p+p-J/y) inBK(p+p-J/y) c c _ p+p- J/y _ c B meson y’p+p-J/y s s q _ K ??? M(p+p- J/y)-M(J/y) Belle PRL 91, 262001 (2003)

  13. X(3872) MX=3872.0±0.6 MeV G<2.3 MeV Belle PRL 91, 262001 (2003)

  14. X3872 is seen in many experiments CDF 9.4s 11.6s X(3872) BaBar D0 X(3872) CMS X(3872)

  15. _ Does it fit into the cc spectrum? This state is expected to decay to p+p-J/y y(4415) y(4150) y(4040) c’ c2 yc2 y” 3872 MeV 2mD0

  16. _ JPC =2--(& 2-+)  DD not allowed yc2 hc2 Spin=0 c D J = 2 P=-1 D0 or D+ q yc2 c (orhc2) J = L P = (-1)L For J = 2 P = (-1)2 = +1 q c q D c D0 or D- Spin=0 yc2 (hc2)DD violates parity

  17. _ _ Lowest possibility is DD* (or D*D) Spin=0 c D J = 2 P=-1 D0 or D+ q c J = L + S P = (-1)L For J = 2, L=1 is OK P = (-1)1 = -1 yc2 q (orhc2) c q D* c D*0 or D*- Spin=1 yc2 (hc2)DD* doesn’t violate parity MD+MD* is the “open charm threshold” for yc2 (&hc2)

  18. Is the X(3872) the yc2? Bf(yc2gcc1) Bf(yc2p+p-J/y) Eichten et al: PRL 98, 162002 (2002) >5 Fermilab 2003 “Look for Xgcc1, you should be flooded by events” yc2(1D) Xgcc1 cc1g J/y Eichten

  19. X(3872)gcc1 ?? Belle PRL 91, 262001 (2003) 3872 Bf(yc2gcc1) Bf(yc2p+p-J/y) <0.9 The X(3872) is not the yc2!!

  20. If not yc2, what??? Measure JPC quantum numbers 1st : find other decay modes: X(3872) g J/y is observed: Gp+p- J/y=(3.4±1.2) GgJ/y BK g J/y BaBar 2009 Belle 2010 PRL 102, 132001 M(g J/y ) M(g J/y )

  21. C(X3872)= + C(X3872) must be (-)(-) = + X3872 g J/y C = - C = - if C(X3872) is + : p+p- system in X3872p+p- J/y must come from rp+p- mr=775 MeV is at kinematic limit p+ C = - r Belle agrees CDF agrees p- X3872 rp+p- lineshape J/y C = - M(p+p- ) M(p+p- )

  22. JPC of X3872 is it 0-+?? spin polarization vectors p+ r p- p* X3872 J/y Τ Τ mutually perpendicular Decays of polarized J/y’s Decays of polarized r’s m+ p+ m- p-

  23. Does the X(3872) JPC = 0-+ ?? m+ qm 0-+ |cosqm| p+ p- y !!! m- |cosy| no, the X(3872) cannot be 0-+

  24. Does the X(3872) JPC = 1++ ?? Τ mutually perpendicular Τ S=0 X(3872) K B x S=0 Sx=0

  25. 1++ fits well m+ qm Belle Data p- c2/dof =1.56/4 c |cosc| p+ c2/dof =0.56/4 m- |cosqm|

  26. CDF angular correlation analysis Only 1++ or 2-+ fit data PRL 98 132002 1++ no adj. params 2- +2 adj. 2arams 1- - O++ 1++ fits well with no adjustable parameters 2-+ has one complex adjustable parameter

  27. JPC of the X(3872) = 1++? …or 2-+? Partial Wave basis: 775 MeV X(3872)r J/y is right at threshold  neglect higher partial waves 3872 MeV 3097 MeV 1++ 2-+ L=0 or 2: S-Wave D-wave S: 1 1,2 L=1 or 3: P-Wave F-wave S: 1,2 1,2 Only 1 amplitude: BLS=B01  1 free parameter: 2 amplitudes: BLS=B11& B12  3 free parameters normalization normalization complex Include relative phase f

  28. JPC of the X(3872) m+ J. Rosner PRD 70, 092023 (2004) qm p+ K c p+ m- c2/dof =1.56/4 c2/dof =4.60/4 1++ fits data well with no free parameters. 2-+ has a free complex parameter; one value gives an acceptable fit c2/dof =0.56/4 c2/dof =5.24/4

  29. _ Is there a 1++ cc state for the X3872? set by: Mcc2=3930 MeV ‘ • Mass is too low? • 3872 vs 3905 MeV theory • G(cc1  gy’) ~180 keV • G(cc1  g J/y) ~14 keV • G(gy’)/G(g J/y)>>1 • measurement: <2 ‘ c’ ‘ c1 T.Barneset al PRD 72, 054026 • Gp+p- J/y=(3.4±1.2)GgJ/y~45 keV ~100x expectaions for an Isospin-violating decay c.f.: G(y’p0J/y)≈0.4 keV

  30. _ Is there a 2-+ cc state for the X3872? set by: My”=3770 MeV • Mass is too high? • 3872 vs 3837 MeV T.J. Burns et al arXiv:1008.0018 • G(hc2  gy’) ~0.4 keV • G(hc2  g J/y) ~9 keV Y. Jiaet al arXiv:1007.4541 hc2 • Gp+p- J/y=(3.4±1.2) GgJ/y ~30 keV • huge for Ispin-violating decay • c.f.: G(y’p0J/y)≈0.4 keV • BKhc2violates factorization • BKhc not seen • BKcc2 barely seen • hc2  DD* expected to be tiny • expt: • G(XDD*)/G(XppJ/y)=9.5±3.1 Y. Kalasnakovaet al arXiv:1008.2895

  31. If not charmonium, what is it?

  32. X(3872)p+p-J/y Mass recent results LHCb Belle CDF ~6000 evts! MX = 3871.61 ± 0.16 ± 0.19 MeV MX = 3871.96 ± 0.46 ± 0.10 MeV MX = 3871.85 ± 0.27 ± 0.19 MeV

  33. X(3872) mass (in p+p-J/y channel only) _ MX(3872) –(MD0+MD*0)= -0.12 ± 0.35 MeV

  34. D0D*0 molecule? __ _ D0-D*0 “Binding Energy” small Dm = -0.12 ± 0.35 MeV …coincidence?? an “old” idea

  35. De Rujula, Glashow & Georgi (1976) PRL 38, 317 (1976) _ predictions: DD* JPC=1++ _ (DD*)molrJ/y p+p- Also: L. Okun& M. Voloshin JETP Lett. 23, 333 (1974)

  36. Search for other states

  37. Search for other states inBK p+p-p0 J/y decays p+ p0 p- c c _ J/y B meson wp+p-p0 s q _ K

  38. M(w J/y) unexpected peak at 3940 MeV Y3940p+p-p0J/y?? Y(3940) w M=3940 ± 11 MeV G= 92 ± 24 MeV S.-K. Choi et al (Belle) PRL94, 182002 (2005)

  39. Y(3940) confirmed BaBar PRL 101, 082001 B±K±wJ/y B0KSwJ/y ratio M(wJ/y) Some discrepancy in M & G; general features agree

  40. _ Does Y(3940)  DD* ? _ BKDD* Belle: PRD 81, 031103 _ _ M(DD*) M(DD*) 3940 MeV 3940 MeV No signal: 3940 MeV is well above DD & DD* threshold _ _

  41. Study e+e- J/y + anything C=- detected J/y C=- e+ e- J/y recoil system is undetected C=+ Recoil Mass:

  42. _ s(e+e-J/y+cc) unexpectedly big Unexpected peak at 3940 MeV e+e-J/y+hc ~30X NRQCD pred

  43. _ _ Use “partial reconstruction” tostudy X3940 DD or DD* J/y e+ e- reconstruct these _ “Recoil” D(*) undetected (inferred from kinematics) _ _ D* (or D) D (or D*)

  44. _ Bf(X(3940) DD*) is large 3940 MeV M = 3942 +7 ± 6 MeV Gtot = 37 +26 ±12 MeV Nsig =52 +24 ± 11evts -6 -15 _ _ -16 e+e- J/y + DD* arXiv:0708.3812 PRL 98, 802001 (2007) Bg subtracted

  45. Use “partial reconstruction” tosearch for X(3940)wJ/y J/y e+ e- “Recoil” J/y undetected (inferred from kinematics) detect these p J/y p p w3p 3940 MeV no signal:

  46. X3940 & Y3940are not the same from: e+e- J/y DD* _ from: B K wJ/y contradiction

  47. _ cc assignments for X(3940), Y(3915) & X(4160)? hc’’’ hc” cc0’ 3940MeV 3915MeV • Y(3915) = cco’? G(wJ/y) too large? • X(3940) = hc”?  mass too low?

  48. 1- - states seen via “radiative return” “initial-state-radiation” photon: gISR kg 1- - E’ Ecm if kg = 3.8~4.5 GeV, E’ = 3~5GeV

  49. Radiative return B-factory energies g ss cc bb 3~5 GeV 10.58 GeV Ecm(GeV)

  50. 233 fb-1 e+e- gisr Y(4260) at BaBar p+p- J/y BaBar PRL95, 142001 (2005) fitted values: M=4259  8 +2 MeV G = 88  23 +6 MeV -6 -9 Y(4260) ~50pb

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