Zb states (All Results from Belle) Jin Li New Hadron Workshop 2012-11-19

Anomalies in (5S) decay hb(2P) hb(1P) (2S) (1S) b(2S) b(1S) (4S) (10860) (11020) JPC = 0 + - 1+ 1 -- 9.50 9.75 10.00 10.25 10.50 10.75 11.00 Mass, GeV/c2 2M(B) +– 260 430 290 190 330 6 2 partial (keV) Belle PRL100,112001(2008) 100 [(5S) (1,2,3S) +–] >> [(4,3,2S) (1S) +–] _  Rescattering of on-shell B(*)B(*) ? Meng and Chao PRD77, 074003(2008) Chen et al., PRD84, 074006(2011) Belle PRL108,032001(2012) (5S)  hb(1,2P) +– are not suppressed expect suppression QCD/mb spin-flip Heavy Quark Symmetry Violation

Anomalies in (5S) decay hb(2P) hb(1P) (2S) (1S) b(2S) b(1S) (4S) (10860) (11020) JPC = 0 + - 1+ 1 -- 9.50 9.75 10.00 10.25 10.50 10.75 11.00 Mass, GeV/c2 2M(B) 260 430 290 6 2 partial (keV) hb production  via intermediate charged states Zb – + + Zb Belle PRL108,032001(2012) (5S)  hb(1,2P) +– are not suppressed expect suppression QCD/mb spin-flip Heavy Quark Symmetry Violation

The analysis of hb(nP)π+π− Studying the decay (5S)  hb(nP) +-: led to observation of Zb Look at the missing mass of a single pion π−, MM(π−) = M(hb π+). Then fit MM(π +π− ) in bins of MM(π−). Fit Function: Significances with systematic: 1 resonance v.s. 0: 6.6 σ 2 resonances v.s. 0: 16 σ

Resonant structure of (5S)  (bb) +– _ (5S)  hb(1P)+- (5S)  hb(2P)+- Belle PRL108,122001(2012) no non-res. contribution Two peaks in all modes phsp Minimal quark content _  bbud  phsp flavor-exotic states M[ hb(1P) π ] M[ hb(2P) π ] Dalitz plot analysis (5S) (1S)+- (5S) (2S)+- (5S) (3S)+- note different scales

Angular analyses for Zb+ arxiv: 1105.4583 Example : (5S)  Zb+(10610) -  [(2S)+] - i (i,e+), [plane(1,e+), plane(1, 2)] cos1 cos2 , rad non-resonant combinatorial Color coding: JP= 1+ 1- 2+ 2- (0 is forbidden by parity conservation) All angular distributions are consistent with JP=1+ , with other JP disfavored at 3  level.

Zb results Angular analysis  both states are JP = 1+ ’ Average over 5 channels M1 = 10607.2  2.0 MeV 1 = 18.4  2.4 MeV MZb – (MB+MB*) = + 2.6  2.1 MeV M2 = 10652.2  1.5 MeV 2 = 11.5  2.2 MeV MZb’ – 2MB* = + 1.8  1.7 MeV Angular analysis  both states are JP = 1+ Decays  IG = 1+ (C= –) Angular plot Phase btw Zb and Zb amplitudes is 0o for (nS) and 180o for hb(mP) ’

Zb amplitudes Properties of Zb amplitudes and phases are consistent with molecular structure.  = 180o  = 0o hb (2S) M(hb), GeV/c2 hb(1P) yield / 10MeV Dip due to destructive interference with non-resonant amplitude in the whole Dalitz plane.  Information on JP of Zb .

Molecule explanation of Zb Wave func. at large distance – B(*)B*  B*B*  =    B B*  =   + – Bondar et al, PRD84,054010(2011) Proximity to thresholds favors molecule over tetraquark Zb  hb(mP) S-wave Zb’  not suppressed Explains Why hb is unsuppressed relative to  Relative phase ~0 for  and ~1800 for hb Production rates of Zb(10610) and Zb(10650) are similar Widths .

More states can be predicted Sbb Sqq 1 States IG(JP) Zb,Zb’ 1+(1+) Wb0,Wb0’ 1−(0+) Wb1 1−(1+) Wb2 1−(2+)

Molecular bottomiums Wb0 Xb Wb1 Wb2 Zb U(?S) Voloshin, PRD 84, 031502 (2011) U(6S) h U(5S) r w g r r p g w B*B* w Up hbphbr Ur Ur hbp Uh hbw Uw hbh g Uw g BB* Ur Uw BB Zb Wb0 Xb Wb1 Wb2 11 0-(1+) 1+(1+) 0+(0+) 1-(0+) 0+(1+) 1-(1+) 0+(2+) 1-(2+) 0-(1-) IG(JP)

Other explanations 1. Threshold effect due to initial pion emission Chen Liu PRD84,094003(2011)   Zb Zb’ B(*) B(*) (5S) (2S) B(*) _ S-wave M [(2S)π] Danilkin Orlovsky Simonov PRD85,034012(2012) 2. Coupled-channel resonance multiple re-scatterings  pole Zb    B(*) B(*)  B(*)  Zb’ + + ... (5S) B(*) _ B(*) _ B(*) _ (2S) (2S) (2S)

Systematic study of B(*)B(*) bound states   3. Deuteron-like molecule B(*) ,,, exchange (5S)  B(*) _ (2S) Ohkoda et al PRD86, 014004 (2012)

Study of Zb→B*B(*) _ For the ϒ(5S) →B*B(*) + channel: _ Fully reconstruct one B meson in five exclusive decay modes. Look at recoil mass of B (for missing B) rM(B) and of the pion (for two B combination) rM(). _

Clear BB* and B*B* signals _ _ Select two peaks Full reconstruction of one B in 5 modes recoil mass _ BB* M(B) Mmiss(B) _ BB _ B*B* BF[ (5S)  B(*)B(*) ] _ preliminary PRD81,112003(2010) Belle 121.4 fb-1 significance Belle 23.6 fb-1 _ BB BB* + BB* B*B* <0.60 % at 90% C.L. (4.25  0.44  0.69) % (2.12  0.29  0.36) % (0  1.2) % (7.3  2.3) % (1.0  1.4) % _ _ _ _ 9.3 5.7 _

Observation of ZbBB* and Zb’B*B* _ Zb’  BB* is suppressed w.r.t. B*B* despite larger PHSP _ M (BB*) Zb preliminary 8 arXiv:1209.6450 Zb’ ? Challenging for tetraquark Molecule  admixture of BB* in Zb’ is small _ phsp Assuming Zb decays are saturated by these channels: recoil mass of  _ M (B*B*) Zb’ 6.8 phsp Crucial input for the models

Absolute branching fractions (3 body) Br((10860)→ (1S) π+π- )= [4.45 ± 0.16(stat.) ± 0.35(syst.)] x 10-3 Br((10860)→ (2S) π+π- )= [7.97 ± 0.31(stat.) ± 0.96(syst.)] x 10-3 Br((10860)→ (3S) π+π- )= [2.88 ± 0.19(stat.) ± 0.36(syst.)] x 10-3 c.f. PRD 81, 112003(2010) f(BB* )=(7.3 ± 2.2 ±0.8) % f(B*B* )=(1.0±1.4 ±0.4) % Br((10860)→ BB* ) = [28.3 ± 2.9± 4.6] x 10-3 Br((10860)→ B*B*π) = [14.1 ± 1.9 ± 2.4] x 10-3 Fractions of sub-modes:

Study of e+e−  (5S)  (nS)00 preliminary BF[(5S)(1S)00] = (2.250.110.20) 10-3 BF[(5S)(2S)00] = (3.790.240.49) 10-3 (2S) in agreement with isospin relations (1S) (1S)π+π- (nS)π+π− fit curve (nS)π0π0 data points (BG subtracted) M miss (0 0) Is there a neutral Zb partner? (2S)π+π-

Fit (2S)00 structure Clear Zbs signals are seen in (2S)π0π0 arXiv:1207.4345 Dalitz plot analysis with Zbs without Clear Zbs signals are seen in (2S)π0π0 Significance of Zb(10610) is 5.3σ (4.9σ with systematics) Zb(10650) is less significant (~2σ) Fit gives M(Zb0(10610) ) =10609±8±6 MeV cf: M(Zb+)=10607.2±2.0 MeV Belle PRELIMINARY

Search for partners of X(3872) C-odd neutral partner search Charged partner X+ search J/ψ+0 channel J/ψη channel χc1γ channel Preliminary PRD 84, 052004 (2011)

Summary Zb+ explanation as molecular states and in (nS)+ and hb(nP) + decays. Observation of Zb+ decays to BB* and B*B* final states in the (5S) B*B(*) + decay study. Zb(10610) decays dominantly to BB*, and Zb(10650) decays dominantly to B*B*. Supporting the molecule explanation. Observation of the neutral partner Zb0(10610) in (5S)(nS)00 decay. Mass of Zb0(10610)= 10609 ± 8 ± 6 MeV . Direct charmonium partner not found. Other recent progress on bottomonium, such as hb(nP), ηb(nS), χb(3P) not covered.

BACKUP

The bottomonium family (1S) (2S) (3S) (4S) 2M(B) BaBar, CLEO collected large ϒ(3S) data because its rich decay trees.

Results of +− missing mass study hb(1P) hb(2P) (1S) (2S) (3S) 121.4 fb-1 2S1S residuals PRL 108 032001 hb(1,2P) JPC=1+- 1st observations 3S1S

(2) (nS)ππ production shape Belle,Phys.Rev.,D82,091106R(2010) Rb Energy scan  mean of shapes of () and hadronic cross section Rb shapes differ by 2.0 

CLEO-c’s e+e− → +− hc cross section (hc +–)  (J/ +–) Γ(Y(4260) → J/ψπ+π−)>508 keV@ 90% C.L.  Large!! X. H. Mo et al., Phys. Lett. B 640 (2006) 182 An interesting comparison! PRL107, 041803 (2011) arXiv:1102.3424 +−hc production is enhanced at Y(4260) +−hb may be enhanced at Yb Substructure of +− hc in Y(4260) has not been studied. Original Motivation for hb search Substructure of +− hb : Enough statistics in Belle’s ϒ(5S) data.

Observation of hb(1P,2P) b(1S)  (5S)hb(nP) +–  b(1S)  Fit Mmiss(+-) spectra [ hb yield] in bins of Mmiss(+-) arxiv:1205.6351 MHF(1S) (11020) Belle : 57.9  2.3 MeV 3 11.00 (10860) hb(1P) PDG’12 : 69.3  2.8 MeV b(1S) 10.75 +- BaBar (3S) (4S) 2M(B) 10.50 BaBar (2S) b(3S) (3S) hb(2P) b(2P) hb(2P) b(1S) 10.25 CLEO (3S) b(2S) (2S) 10.00 hb(1P) b(1P) pNRQCD LQCD  9.75 Kniehl et al, PRL92,242001(2004) Mmiss (+-) (n) Meinel, PRD82,114502(2010) (1S) 9.50 b(1S) MHF(1S) Belle result decreases tension with theory JPC = 0 + - 1 -- 1 + - (0,1,2)++ First measurement  = 10.8 +4.0 +4.5 MeV –3.7 –2.0 as expected

First evidence for b(2S) e+e-(5S)hb(2P) +–  b(2S)  MHF(2S) = 24.3 +4.0 MeV –4.5 First measurement arxiv:1205.6351 PRL pNRQCD LQCD b(2S) Belle 4.2 w/ syst In agreement with theory Mmiss (+-) (2) (2S) = 4  8 MeV, < 24MeV @ 90% C.L. expect 4MeV Branching fractions Expectations BF[hb(1P)  b(1S) ] = 49.25.7+5.6 % BF[hb(2P)  b(1S) ] = 22.33.8+3.1 % BF[hb(2P)  b(2S) ] = 47.510.5+6.8 % 41% 13% 19% –3.3 –3.3 Godfrey Rosner PRD66,014012(2002) –7.7 c.f. BESIII BF[hc(1P)  c(1S) ] = 54.38.5 % 39%

Observation of Y(5S)gY(1D)p+p- Y(1S)[m+m-]p+p-gg final state Three peaks in MM(p+p-): Y(2S) p+p- Y(1D) p+p- Y(2S)[Yp+p-]h[gg] reflection After cb(1P)gYg selection preliminary statistical significance 9s B[Y(5S)gY(2S)p+p-] = (7.51.10.8) 10-3 (cross check) B[Y(5S)gY(1D)p+p-] B[Y(1D)gcb(1P)ggY(1S)gg] = (2.00.40.3) ×10-4 P.S. : An evidence of Y(1D) was seen in inclusive MM(p+p-) spectra 29

Angular Analysis JP = 1+, 1−, 2+, 2− Zb velocity is very small ( β<0.02)  measure all pion momenta in the c.m. frame. (5S)→Zb((nS),hb+ π1)π2 1= (π1,e+) 2= (π2,e+) = (plane(π1,e+)),plane(π1, π2)) JP = 1+, 1−, 2+, 2− Example: (5S)→ Zb(10610) π2 → (2S)π1 π2 Non-resonant

Angular Analysis (hb final state) JP = 1+, 1−, 2+, 2− Example: (5S)→ Zb(10610) π2 → hb(1P)π1 π2 Probabilities at which other JP hypotheses are disfavored with respect to 1+