Exotic hadronic states XYZ

Transcription

1 Exotic hadronic states XYZ Yu-Ping Guo (KPH, Mainz University) International School of Nuclear Physics 37 th Course Probing Hadron Structure with lepton and Hadron Beams Erice-Sicily September 16-4, 15

2 Hadrons Quark model: Mesons Baryons Exotic hadrons: Glueball Hybrid Multiquark state Molecule

3 Static Quark Anti-quark Potential Coulomb-like + linear potential At small distance: one-gluon exchange dominate spin-spin + At large distance: confinement Mass splitting spin-orbit tensor + [PRD 7, 546 (5)] Solve Schrödinger equation (heavy quark mass, m q >> Λ QCD, non-relativistic) à states in the spectroscopy k is the string constant of QCD string between quark and anti-quark 3

4 Charmonium Spectroscopy [PRD 7, 546 (5)] Notation: S+1 L J J PC P=(-1) L+1 C=(-1) L+S solid line: discovered dashed/dotted line: predicted Z(443) 1 + Z(45) Z(45) Z(4) 1 + Z c (39) Z c (3885) 1 + Z c (4) Z c (45) X(387) 1 ++ X(3915) ++ X(394) Y(394) Y(414) X(435) / ++ Y(48) 1 -- Y(46) 1 -- Y(436) 1 -- Y(466)

5 Charmonium Production Direct Production Initial State Radiation J PC =1 -- J PC =1 -- Double Charmonium Production J/ψ, ψ(s) C=+ Two Photon Production untagged case: J PC = ±+, ±+ 5

6 Charmonium Production B-meson Decays Charmonium Transitions J PC = -+,1 --,1 ++ K (*) pp-bar Annihilation J =, J = 1 All quantum numbers 6

7 Experiments 7 CLEO-c

8 X(387) 8

9 Discovery First observation: B ± à K ± π + π - J/ψ Production: Decay: B meson decays (Belle, BaBar, LHCb) pp(-bar) annihilation (CDFII, D, LHCb, CMS) Vector charmonium(-like) transition (BESIII) π + π - J/ψ, π + π - π J/ψ, D D π, D D*, γj/ψ, γψ Events / 3 MeV/c 15 5 [PRL 91,61(3)] Belle B decay 15M [PRL93,71(4)] CDF-II pp annihilation, inclusive pb -1 [PRL Data 11, 91 (14)] Total fit BESIII Background Y(46) decay M( + J/ ) (GeV/c ) 9

10 Mass and Width Measurement Mass: ±.17 MeV/c Close to D D * threshold: ±.17 MeV/c binding energy : -.11±.4 MeV/c, large radius Only measurements from π + π - J/ψ are used Mass (MeV/c ) Experiments Note ±.7±. BESIII Y radiatve transition [PRL 11 91] ±.48±.1 LHCb pp annihilation [EPJC 73 46] ±.7±.19 Belle B +,B decay [PRL ] ±.16±.19 CDFII pp-bar annihilation [PRL 3 151] ±.6±.1 BaBar B + decay [PRD 77 11] ±1.5±.4 BaBar B decay [PRD 77 11] ±3.1±3. D pp-bar annihilation [PRL 93 16] Width: <1. MeV [PRD 84, 54 (11) Belle]

11 Quantum Number Decay into γj/ψ: C=+ state CDFII narrow it to 1 ++ or -+ [PRL 98,13 (7)] Use helicity-amplitude analysis, compare angular distribution LHCb: -+ rejected > 8σ [PRL 1, 1 (13)] 1fb -1 ππ in X(387)à π + π - J/ψ decay: Dominant contribution: ρ (CDF, Belle) Isospin of X(387) or 1 : X(387)à ρj/ψ isospin violate 1: charged partner not found, large X(387)à ωj/ψ branching fraction [PRD 84, 54] (11) Belle S-wave 11

12 What s X(387) arxiv: As conventional charmonium J PC =1 ++, 3 P 1 state χ c1 (P) Potential model predicted mass: 395 MeV (NR)/ 3953 MeV (GI), 5~7 MeV higher Decay to ρj/ψ isospin and OZI violating process As Molecule: Small binding energy, large radius Production characteristics in pp(-bar) collision similar to ψ(s) [D: PRL 93, 16 (4)] [LHCb: EPJC 7, 197 (1)] [CMS: JHP 134, 154 (13)] Ratio of X(387)à γj/ψ to X(387)à π + π - J/ψ:.4±.5 [BaBar: PRL 131 (9)] [PRL (11)] Consistent with molecule calculation when D + D *- and D S+ D *- S included [PRD 86(11) 1137 (1)] 1

13 What s X(387) As Molecule (cont.): Ration of X(387)à γj/ψ to X(387)à γψ(s): As tetraquark:.31±.57 [BaBar: PRL 131 (9)] [LHCb: NPB (14)] Pure DD* assignment failed at this point Two states in B + and B decays [PRL99, 183 (7)] Not confirmed by Belle and BaBar [PRD (11)] (.71 ±.96 ±.19) MeV [PRD (5)] As mixture of difference configurations X(387)> = c 1 cc> + c DD*> [EPJC 73(3): 351] [PTEP 9 93D1] 13

14 Y STATES

15 Discovery First state - Y(46), discovered in ISR process at BaBar e + e - à γ ISR π + π - J/ψ M > 4 GeV above DD threshold Not observed in inclusive hadron cross section Not observed in open charm pair cross section Confirmed by CLEO and Belle Quantum number: 1 -- R Events / MeV/c [PRL95, (5)] BaBar m( + - J/ ) (GeV/c ) [PLB 66, 315 (8)] /d.o.f=1.5 BES Ecm (GeV) R exp R the R con R int R res R BW 15

16 Y Family from ISR [PRL1,5 (13)], 967 fb -1 [PRD 91,17 (14)], 98 fb -1 Entries/ MeV/c 3 [PRD86,51 (1)], 454 fb -1 Events /5 MeV/c M[ + - (S)] (GeV/c ) [PRD89,1113 (a) (14)], fb -1 ψ(s) J/ψπ π background m(ψ(s)π π ) (GeV/c ) 16

17 Over Population 1 -- States arxiv: π + π - J/ψ π + π - ψ(s) c c-bar Above charm threshold, 5 expected, 7 observed No mixing with ψ states No mixing among final states Y(46) only to π + π - J/ψ (small hint.4σ in π + π - ψ(s)) Y(436) and Y(466) only to π + π - ψ(s) 17

18 New Information from Scan fb -1 data at BESIII 18 energy points PRL1, 5 ) -1 Luminosity (pb 3 PRL115, s(gev) Cross section VS E cms π π J/ψ π +, π -, h c ωχ c Information limited due to small statistics Maybe exist fine structure of Y(46)?? PRL111, 41 PRL114, 93 18

19 What s Y States As conventional charmonium J PC =1 -- No candidates from potential model prediction in nearby mass Missing from open charm production cross section Missing from inclusive hadron cross section As charmonium hybrid Predicted mass ~4. GeV [PRD78, 563 (Guo); 9454 (Dudek)] Decay to DD 1 should be large, need experimental result [PLB 68 15] Other configurations: Hadrocharmonium, molecule, terequark, threshold effect 19

20 Z C + STATES

21 Z(443) First observation: Belle, Bà Kπ ± ψ(s), 65 fb -1 data at ϒ(4S) Fit to the mass spectrum of π ± ψ(s), 6.5σ Not confirmed by BaBar, found data can be explained by K * reflections: Two dimensional analysis, 413 fb -1 data at ϒ(4S) [PRL, 141 (8)] [PRD79, 11 (9)] Updated Belle results: Two dimensional analysis using same data as first publication Four dimensional amplitude analysis, 711 fb -1 ϒ(4S), Z(443) favor 1 + Larger width, higher mass [PRD8, 314(R) (9)] [PRD88, 746 (13)] 1

22 Confirmation of Z(443) 5176±174 B à ψ K + π -, ψ à µ + µ - [PRL 11, ] 3 fb -1 Z Significance: >13.9σ Im A. LHCb Four dimensional analysis: Φ=(M Kπ, M ψ π, θ ψ, ϕ) Mass and width consistent with Belle latest result J P =1 + Second peak: 439± MeV/c ± MeV Z Re A Argand diagram resonance behavior character

23 Z(443) in πj/ψ Belle B à K - π + J/ψ, J/ψà l + l fb -1 data at ϒ(4S), 999±19±5 signal events Four dimensional analysis: Φ=(M Kπ, M ψπ, θ ψ, ϕ) Z(4) + observed 4 /c Events /.54 GeV J P = Global significance: 6. σ GeV /c < M (K, ) < 3. GeV /c K* contribution [PRD 9, 19 (14)] Evidence of Z(443) + 4 /c Events /.54 GeV Z(4) contribution Global significance: 4. σ Argand diagram shows resonance character GeV /c < M (K, ) < 3. GeV /c Z(443) included M (J/, ), GeV /c 4 Z(443) contribution M (J/, ), GeV /c 4 3

24 Z c States from Y s Iso-triplet Events / (.1 ) 18[PRL1, 51(13)] 436 MeV 16 >8 σ ±48 events M(π J/ψ) (GeV/c [PRL11, 1 (14)] 5±41 events J P favor 1 + ) Events / (.1 ) [PRL115, 13(15)] 43 MeV M(π J/ψ) (GeV/c ) Z c (39) ±, BESIII, Belle, CLEO-c data Z c (3885) ± BESIII: single and double D-tag 48±84 for ψ(377) Γ(Z c (3885)->DD*) Γ(Z c (39)->πJ/ψ) > σ = 6.±1.1±.7 4

25 Z c States from Y s [PRL111, 41 (13)] Iso-triplet [PRL11, 131 (14)] 8.9 σ.1 σ > σ 41±47 events 53 events [PRL113, (14)] >5 σ ) Events/(5MeV/c [arxiv:157.44] 3 4.3GeV+4.6GeV 7.4 σ RM( )(GeV/c ) ) Events/(5MeV/c s=4.3 GeV 15 s=4.6 GeV RM( )(GeV/c ) Z c (4) ±, /Z c (45) ±, BESIII, need confirmation Γ(Z c (45)->D*D*) Γ(Z c (4)->πh c ) = 1±5 5

26 Summary of Z c States State Mass (MeV/c ) Width (MeV) Note 3899.±3.6±4.9 46±± BESIII, π ± J/ψ ±6.6±4.5 63±4±6 Belle, π ± J/ψ 3886±4± 37±4±8 CLEO-c*, π ± J/ψ Z c (39) ±, ±1.5±4. 4.8±3.3±11. BESIII, DD* single tag ±1.± ±.1±.6 BESIII, DD* double tag 394±9±5 -- CLEO-c*, π J/ψ ±.3±.7 9.6±8.±8. BESIII, π J/ψ Z c (4) ±, BESIII Z(443) 4.9±.8±.7 7.9±.7±.6 π ± h c 46.3±.6±.7 4.8±5.6±7.7 (D*D*) ±, single tag 43.6±.3±3.9 - π h c ±3.1 3.±6.±1. (D*D*), double tag 4485± Belle, π- ψ(s) 4475± ± LHCb, π- ψ(s) Z(4) Belle, π- J/ψ Z(45) 451± Belle, π+ χ c1 Z(45) Belle, π+ χ c1 6

27 What s Z c states Experimental information: At least four quarks Mass close charm meson pair threshold Product in two pattern: B meson decay Y states: isospin triplet states (similar states in bottomonium system, Z b states) No mixing between them Possible of Z c Molecule Tetraquark Threshold effect Hadrocharmonium 7

28 Connection between XYZ Y à Z Z c states are produced from Y states above 4 GeV Z c cross section vs E cms measurement Y à X e + e - à γx(387) [PRL11, 91 (14)] 8

29 Summary Great progress in exotic hadrons in the past decades Properties of X(387) measurements: mass, quantum number, production and decays Overpopulation of 1 -- states above 4 GeV Unexplained 1 + (probably) states discovered Building relations between exotic states Theoretical progress Better understanding of threshold structures Systematic analysis of various processes from difference scenarios THANK YOU 9

30 3

31 X(387) Radiative Decays Ratio of X(387)à γψ(s) to γj/ψ: Theoretical predictions: Pure DD* molecule: (3-4) -3 ;Charmonium: 1.-15; Mixture:.5-5 Experimental measurements: BaBar: 3.4±1.4, 3.5σ [PRL, 131 (9)] Belle: 9% C.L [PRL7, 9183 (11)] LHCb:.46±.64±.9, 4.4σ [NPB 886, 665 (14)] B + à X(387)K +, X(387)à γψ, ψà µ + µ - 591±48 events 36.4±9. events 31

32 Events / (.4 GeV ) Events / (.4 GeV ) X(387) in Bà X(387)Kπ 711 fb -1 data, D fit B à X(387)(K + π - ) (7.9±1.3±.4) -6 (a) E (GeV) 3 (a) 7 σ E (GeV) Events / (.4 GeV/c ) Events / (.4 GeV/c ) (b) (GeV/c ) 3 (b) M J/ B + à X(387)(K π + ) (.6±3.±.9) σ (GeV/c ) M J/ [PRD91, 511(R) (15)] Events / (.51 GeV/c ) Events / (.1 GeV/c ) 4 (a) M K M K K*(89) (GeV/c ) 8 (b) (GeV/c ) non resonant 3

33 Y to γχ cj 33

34 Z(45) and Z(45) B à K + π - χ c1 65 fb -1 [PRD78, 74 (8)] >5 σ 34