A Discovery of the tetraquark by the Belle Experiment

Transcription

1 A Discovery of the tetraquark by the Belle Experiment Sookyung Choi (For the Belle Collabora5on) Gyeongsang Na5onal University JAGIELLONIAN Symposium, Krakow, Poland, June

2 Outline X(3872) Charged Charmonium- like states : Z(4430), Z(4200), Charged Bo\omonium- like states : Z b s More charged charmonium- like states : Z c (3895),, more BESIII Z c s 2

3 Charmonium & Bo\omonium spectrum 3

4 cc assignments for the XYZ mesons? S Olsen, Front. Phys. 10, (2015) no unassigned levels for the Y(4260) & Y(4360) Y(4360) Y(4260) X(4160) Z(4430) Z 2 (4250) Z(4200) the (5) charged Zs must have a minimal quark content of ccud Z(4050) Close to D*D* threshold X(3940) Y(3915) Z c (3900) X(3872) Close to D*D threshold the X(3940) & X(4160) as the η c (3S) & η c (4S) would imply huge hyperfine splittings for n=3&4 the Y(3915) mass and Γ(Y ωj/ψ) are too high for the χ c0 (2P) Neutral XYZ states Charged Z states 4

5 The list of XYZ states keeps growing S Olsen, Front. Phys. 10, (2015) 5

6 Models for XYZ Mesons Tetra- quarks Hybrids u c c u c c u c π c u meson - molecules u c u c diquarkonium (diquark- dian5quarks) (π) c c (π) hadro - quarkonium Ispin triplet & singlet? neutral doublet charged doublet X(3872)YZ should have partner states: Three missing states in any pictures 6

7 The X(3872) B Kπ + π - J/ψ ψ π + π - J/ψ X(3872) π + π - J/ψ X(3872) aher 11 years (& >1000 cites, by 2014 Nov) 7

8 What do we know about the X(3872)? Belle BaBar BESIII CMS M X(3872) = ± 0.17 MeV m D 0 + m D* 0 = ± 0.17 MeV B.E. = 100 ± 210 kev Γ X(3872 < 1.2 MeV (90% CL) Y(4260) γx(3872)? 8

9 CDF PRL 98, : J PC = 1 ++ or J PC =1 ++ Belle PRD 84, (R): J PC = 1 ++ or , LHCb PRL 110, : J PC = 1 ++

10 Radia5ve decays of X(3872) : a probe of the nature of X(3872) X(3872) γ ψ, γ J/ψ C=+1 BaBar Belle LHCb From T. Skwarnicki (Moriond QCD 2015) 10

11 Strong decay X(3872) DD* 2- dim. Fit PRD81, (2010) B K D 0 D *0 605 fb σ B + & D0 BD 0 π D 0 0 D *0 K M = fb -1 B KD 0 D 0 π 0 ±0.5 MeV 347fb -1 D *0 D 0 γ D *0 D 0 π 0 BaBar PRD77, (2008) Belle PRL97, (2006) Both groups saw a high mass value & a Bf(DD*) 10x Bf(π + π - J/ψ) M = MeV Agrees with Mass from ππj/ψ mode Γ(BW) = MeV B(B K X 3872 )xb(x 3872 D *0 D 0 ) = (0.80±0.20± 0.10)x

12 Isospin of the X(3872) No X(3872) charged partner states in B Kπ + π 0 J/ψ (If M(X + ) > m D ++m D* MeV, Γ(X + ) may be wide) Belle PRD 84, (R) & BaBar PRD 71, B 0 K - π + π 0 J/ψ m D ++m D* 0 B + K 0 π + π 0 J/ψ m D ++m D* 0 M(π + π 0 J/ψ) (GeV) M(π + π 0 J/ψ) (GeV) 12

13 Isospin mixing in the X(3872) X(3872) ρ J/ψ ω J/ψ Isospin viola5ng decay modes (each other) with similar BFs X(3872) D 0 D* 0 ~ 10 x BF(X J/ψππ ) Eric Braaten: S- wave DD* molecular components must exist D 0 D + D* - D* 0 X(3872) is mostly D 0 D* 0 > mixture of I=0 >& I=1> 13

14 CDF: ~85% of pp X(3872) is prompt D0: prompt pp X(3872)X pp ψ X D0 PRl 93, prompt X(3872) & ψ have similar produc5on characteris5cs (i.e. p T - & y - dependence, isola5on, etc.) D 0 B X(3872)+X c c ψ D* 0 14

15 hybrid model for the X(3872) e.g., Takizawa & Takeuchi PTEP 9, 093D01 D 0 D + D* - c c D* 0 X ωj/ψ decays X ρj/ψ decays produc5on 15

16 Charged Charmonium- like states : Z(4430), Z(4050), Z(4250), Z(4200) (new) and Z(3885).. 16

17 Belle : 660M BB The Z(4430) + Found by Belle in 2007 S- K Choi et al Belle: PRL R. Mizuk et al Belle: PRD σ M(π + ψ ) Charged state cannot be Not seen by BaBar But both Data seems consistent Belle published two more results Latest one uses 4D amplitude analysis 17

18 Quantum numbers of the Z(4430) + Z(4430) + π + ψ in B Κ - π + ψ K Chilikin et al Belle: PRD (2013) Belle : 772 M BB 6.1σ Results from 4D fit M 2 (π + ψ ) 4485 MeV is favored over 0 - by 3.4 σ 18

19 Is Z(4430) + a resonance or resca\ering effect? Taken from T. Skwarnicki (Moriond QCD 2015) LHCb 19

20 The Z(4200) + New from Belle: 4- dim analysis of B K + π - J/ψ K Chilikin et al Belle: PRD (arxiv: ) (2014) 20

21 New state Z(4200) + π - J/ψ 6.2 σ is favored over 0 - by 6.1σ and 2 - by 4.4 σ 21

22 Z(4430) + π - J/ψ B Kπ + J/ψ with Z(4430) 4.0σ no Z(4430) This may support the Z(4430) as an hadro- charmonium other than conven5onal tetraquark state M(Z c (4430))-M(Z c (3900)) = 589 ± 30 MeV M(ψ ) M(J/ψ) = 589 MeV Is Z(4430) a radial excita5on of the ground state of Z c (3900)? 22

23 Z(4050) + and Z(4250) + π + χ c1 in B 0 Κ - π + χ c1 PRD 78, (2008) > 5 σ 23

24 Charged Bo\omonium- like Z b states and neutral partner state: Z b (10610) +, Z b (10650) + and Z b (10610) 0 24

25 The Y(4260) σ(e + e - hadrons) found by BaBar in e + e - γ ISR π + π - J/ψ Confirmed by Cleo, Belle and BES BaBar PRD86, Γ(π + π - J/ψ) is large, 10~100 charmonium E cm (GeV) M(π + π - J/ψ) (GeV) Is there a b- quark version of Y(4260)? 25

26 bo\omonium bb mesons New Measurement of R b, R ϒ(nS)ππ Is there any anomaly in ϒ(4S,5S) π + π - ϒ (1S)? (Con5nuum subtrac5on and ISR correc5on applied) Lum ~1/20 th σ ~1/5 th Signal ~ 6 2S 3S 4S 5S Belle: PRL parent Γ(Y 4,5S ππϒ 1S ) ϒ(4S) ϒ(5S) 1.75 ± 0.35 kev 590 ± 110 kev Energy scan 26

27 ϒ(5S) π + π - ϒ (1,2,3S)? Belle PRL 108, (2012) c - 1 π + π - M 2 (ϒπ ± ) Υ(3S)π + π - Υ(2S)π + π - M 2 (ϒπ ± ) π + π - Υ(1S)π + π - M 2 (ϒπ ± ) M 2 (π + π - ) 27

28 ϒ(5S) π + π - ϒ (1S)? Belle PRL 108, (2012) c - 1 Υ(3S)π + π - π + π - M 2 (ϒπ ± ) M(ϒ(3S)π ± ) Υ(2S)π + π - π + π - Υ(1S)π + π - M(ϒ(2S)π ± ) M(ϒ(1S)π ± ) 28

29 ϒ(5S) π - Z + b1,2 Belle PRL 108, (2012) c - 1 π + ϒ (1,2,3S) π + 10,610 MeV 10,660 MeV ϒ (3S) ϒ (2S) ϒ (1S) M(ϒ(nS)π + ) max 29

30 Bo\omonium spectrum ϒ(5S) π - Z b1,2 + Belle PRL 108, (2012) c - 1 π + h b (1P, 2P) π + 10,610 MeV 10,660 MeV 30

31 Summary of parameter measurements m B +m B* 2m B* Belle PRL 108, B d b B* d b Z b (10610) M= ±2.0 MeV Z b (10650) M= ±1.5 MeV Γ=18.4±2.4 MeV Γ=11.5±2.2 MeV 31

32 Z b (10610) BB* & Z b (10650) B*B* ϒ(5S) π - (BB*) + ϒ(5S) π - (B*B*) + Z b (10610) ± Z b (10650) ± M(BB*) arxiv : M(B*B*) Bf(Z b (10610) BB* Bf(Z b (10610) π + (bb) =6.2±0.7 Bf(Z b (10650) B*B* =2.8±0.4 Bf(Z b (10650) π + (bb) 32

33 Z b 0 search in ϒ(5S) π 0 π 0 ϒ (1,2S) Belle PRD (2013) 33

34 More Z c states 34

35 Discovery chain from Y(4260) to Z b(c) s by BaBar in e + e - γ ISR π + π - J/ψ Y(4260) discovered Is there a b- quark equivalent???? Yes, & it decays to Z b states Are there c- quark versions of Z b s? ϒ(5S) π + Ζ b - π + π - ϒ (1S) Yes, many Z c s!! 35

36 Z c (3895) by Belle e + e - (γ)y(4260) π - Z c (3895) + π + π - J/ψ PRL 110, (2013) arxiv: Y(4360) Y(4260) X(4160) X(3940) Z(4430) Z 2 (4250) π + Z(4050) Y(3915) Z c (3900) X(3872) BESIII data clearly establish J P =1 + From DD* π - Neutral XYZ states Charged Z states Mass = ( ± 6.6 ± 4.5) MeV Width = (63 ± 24 ± 26) MeV Fraction = (29.0 ± 8.9)% (stat. error only) Significance = 5.2 σ 36

37 Y(4260) π - Z c (3900) + π π + J/ψ BESIII: PRL 110, arxiv: Mass = (3899.0±3.6±4.9) MeV Width = (46±10±20) MeV Fraction = (21.5±3.3±7.5)% Significance > 8 σ 37

38 Z c states from BESIII 38

39 Summary of Z c states discovered in the BESIII experiment From Xu Xinping, C. Yuan (QWG2014) 39

40 Z(3900) 0 & Z(4020) 0 search at Belle From Anna Vinokurova at CHARM2015 arxiv : 1501:06351 JHEP.. M(η c π + π - ) (GeV) M(η c π + π - ) (GeV) 40

41 X(3872) and other 1 + XYZ states Molecules Level Diagram? (By S. Olsen Front. Phys. 10, (2015) The J P =1 + bo\omonium states? (See above ref.) 41

42 Belle discovered many XYZ states. Summary List of XYZ mesons keeps growing, however, their nature is s5ll in a mystery. Remains opportuni5es for LHCb and BelleII. 10 years aher the X(3872) s discovery, this is the most highly cited B- factory paper and BE = (m D* 0+ m D 0) - M X(3872) gets smaller, and now the BE= MeV Models for the X(3872)YZ suggest the existence of addi5onal states Z(4430)+ from Belle is confirmed and J P is conclusively 1 +. Argand plot (LHCb) shows resonance behavior Charge and quantum numbers rule out conven5onal charmonium interpreta5on But s5ll non- resonant interpreta5on (resca\ering) possible. NEW charged state Z(4200) + is observed in B J/ψ π + K - decay. The quantum number is 1 +. Evidence of the Z(4430) + π + J/ψ is found. Z b (10610) +, Z b (10650) + and Z b (10610) 0 are the first candidate of ispin triplet in Belle. Many Z c states are recently discovered from BESIII (Belle) : including two sets of Isospin triplet states Z c (3900) and Z c (4020). 42

43 Back- up slides 43

44 M = ±0.6±0.5 MeV X(3872) ρj/ψ π + π - J/ψ X(3872) / γχ c1 M X(3872) m D 0+m D* 0 C=+ X(3872) 1 3 D 2 (ψ 2 ) 44

45 The Belle experiment TOF counter Peak luminosity recorded at KEKB: L=2.1 x /cm 2 /sec with crab caviges 45

46 QCD hybrid? c c lightest 1 ++ hybrid ~4.4 GeV excited- state hybrids ground- state hybrids charmonium L Liu et al., JHEP 1207, 126 (2012) (Hadron Spectrum Collabora5on) 46

47 B 0 X(3872)K + π - PRD91, (R) (2015) B(B 0 X(K + π ) K*+NR ) B(X J/ψπ + π ) = (7.9±1.3±0.4) x 10 6 (B(B + X(K 0 π ) K*+NR ) B(X J/ψπ + π ) = (10.6±3.0±0.9) x 10 6 ) [both K*and (K+π ) NR ] 47

48 Results by Adding Z + (LHCb) K* vetoed 4- dim amplitude analysis B Kπ + ψ PRL 112, (2014) 48

49 Argand plot for Z c (4200) + Clearly shows Resonance-like change of the amplitude Much larger errors and impossible to Draw any conclusion yet. Unlike LHCb, Belle have two plots for two helicity amplitudes including higher waves. For S-wave, H 1 = H 0 49

50 Belle PRD 82, R (2010) Energy scan to search for anomalous structure R ϒ(nS)ππ = Total 29.8 c - 1 R b = BaBar PRL 102, (2009) ± GeV Recall Y(4260) with anomalous Γ(J/ψ π + π - ) Is there a ϒ b equivalent close to ϒ(5S) 50

51 B- B* & B*- B* molecules?? B Z b (10610) ± Z b (10650) ± b B* b b B- B* molecule B* b B* B*- B* molecule M Zb (10610) (M B +M B* ) = ± 2.1 MeV M Zb (10650) 2M B* = ± 1.8 MeV Slightly unbound threshold resonances?? Belle: M= ±2.0 MeV Γ=18.4±2.4 MeV M= ±1.5 MeV Γ=11.5±2.2 MeV PDG: M B + M B* = ±0.6 MeV M B* + M B* = ± 1.0 MeV 51

52 BESIII collected 5 /ƒ above 4GeV for XYZ study BESIII Y(4260) γx(3872) 52

53 CLEOc data at 4.17 GeV: M = 3885±5±1 MeV Γ = 34±12±4 MeV 81 ± 20 events 6.1σ 53

54 Z c (3900) 0? ( a neutral isospin partner state) Z c (3900) 0 First hint from 54

55 Search for Z c (3900) 0 Z c (3900) 0 This establishes the Isospin triplet of Z c (3900) 55