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This article explores the various color-singlet combinations of quarks and gluons, including pentaquarks, H-diBaryons, glueballs, and tetraquark mesons. It also discusses the puzzles of decays of the exotic resonance Yb near the Υ(5S) state and the observation of hb(1P,2P) decays. Measurements of the hb(1S) and hb(2S) masses are also presented.
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“Exotic” bottomonium states Alex Bondar BINP, Novosibirsk Belle Collaboration (Hadrons from Quarks and Gluons, January 16, 2014, Hirschegg, Austria)
Constituent Quark Model Gell-Mann The model was proposed independently by Gell-Mann and Zweig in 1964 with three fundamental building blocks: 1960’s (p,n,L) Þ 1970’s (u,d,s): mesons are bound states of a of quark and anti-quark: Zweig baryons are bound state of 3 quarks:
What about 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
e+e-hadronic cross-section BaBar PRL 102, 012001 (2009) (1S) (5S) (6S) (4S) (2S) (3S) (4S) Belle took data at E=108671MэВ 2M(B) 2M(Bs) _ e+ e- ->(4S) -> BB,whereBisB+orB0 _ _ _ _ _ e+ e- -> bb ((5S)) ->B(*)B(*), B(*)B(*)p, BBpp, Bs(*)Bs(*), (1S)pp, X … main motivation for taking data at (5S)
Puzzles of (5S) decays Anomalous production of (nS)+- with 21.7 fb-1 PRD82,091106R(2010) (MeV) PRL100,112001(2008) 102 Rescattering(5S)BB(nS) (2) Exotic resonance Yb near (5S) Simonov JETP Lett 87,147(2008) analogue of Y(4260) resonancewith anomalous (J/+-) Rb Dedicated energy scan shapes of Rb and () different (2) (5S) is very interesting and not yet understood Finally Belle recorded 121.4fb-1 data set at (5S)
e+e- -> hcp+p- by CLEO Observation of e+e- → +- hc by CLEO PRL 107,041803 (2011) Ryan Mitchell @ CHARM2010 Energy dependence of the cross section Enhancement of (hc+-)@ Y(4260) (hb +-) is enhanced @ Yb? Belle search for hb in (5S) data
Observation of hb(1P,2P) - - -- JPC = 0+ 1 1 + e+e-(5S) hb(nP) +– reconstructed, use Mmiss(+-) (Pe+e- – P+-)2 (11020) 11.00 (10860) PRL108,032001(2012) +- 10.75 raw distribution (4S) 2M(B) hb(2P) 10.50 (3S) b(3S) residuals b(2P) hb(1P) hb(2P) 10.25 (2S) b(2S) b(1P) 10.00 hb(1P) MHF(1P) 9.75 Belle PRL 109. 232002 (2012) consistent with zero, as expected MHF(1P) = +0.8 1.1 MeV MHF(2P) = +0.5 1.2 MeV (1S) 9.50 b(1S) (0,1,2)++ Large hb(1,2P) production rates c.f. CLEO/BESIII e+e- hc +-
Observation of hb(1P,2P) - - -- JPC = 0+ 1 1 + e+e-(5S) hb(nP) +– reconstructed, use Mmiss(+-) (Pe+e- – P+-)2 (11020) 11.00 (10860) PRL108,032001(2012) +- 10.75 raw distribution (4S) 2M(B) hb(2P) 10.50 (3S) b(3S) residuals b(2P) hb(1P) hb(2P) 10.25 19% (2S) b(2S) b(1P) 10.00 hb(1P) 13% 9.75 41% Belle PRL 109. 232002 (2012) consistent with zero, as expected MHF(1P) = +0.8 1.1 MeV MHF(2P) = +0.5 1.2 MeV (1S) 9.50 b(1S) (0,1,2)++ Large hb(1,2P) production rates c.f. CLEO/BESIII e+e- hc +- hb(nP) decays are a source of b(mS)
e+e-(5S)hb(nP) +– b(1S) (11020) 11.00 (10860) +- 10.75 (4S) 2M(B) 10.50 (3S) b(3S) b(2P) hb(2P) 10.25 (2S) b(2S) b(1P) 10.00 hb(1P) Observation of hb(1P,2P) b(1S) 9.75 Mmiss (+-) (n) (1S) 9.50 b(1S) - - First measurement = 10.8 +4.0+4.5 MeV -- JPC = 0+ –3.7 –2.0 (0,1,2)++ 1 1 + reconstruct MHF(1S) Belle : 57.9 2.3 MeV 3 arxiv:1205.6351 PDG’12 :69.3 2.8 MeV hb(1P) b(1S) BaBar (3S) BaBar (2S) hb(2P) CLEO (3S) b(1S) pNRQCD LQCD Kniehl et al, PRL92,242001(2004) Meinel, PRD82,114502(2010) MHF(1S) Mizuk et al. Belle PRL 109 (2012) 232002 Belle result decreases tension with theory as expected
e+e-(5S)hb(nP) +– b(1S) Observation of hb(1P,2P) b(1S) Mmiss (+-) (n) First measurement = 10.8 +4.0+4.5 MeV –3.7 –2.0 PRL101, 071801 (2008) reconstruct MHF(1S) BaBar (3S)b(1S) Belle : 57.9 2.3 MeV 3 ISR arxiv:1205.6351 PDG’12 :69.3 2.8 MeV b(1S) hb(1P) b(1S) BaBar (3S) b(1P) BaBar (2S) PRL103, 161801 (2009) BaBar (2S)b(1S) hb(2P) CLEO (3S) b(1S) ISR b(1S) pNRQCD LQCD Kniehl et al, PRL92,242001(2004) Meinel, PRD82,114502(2010) PRD81, 031104 (2010) Mizuk et al. Belle PRL 109 (2012) 232002 Belle result decreases tension with theory CLEO (3S) as expected
e+e-(5S)hb(2P) +– b(2S) First evidence for b(2S) Mmiss (+-) (2) Mizuk et al. Belle PRL 109 (2012) 232002 MHF(2S) = 24.3 +4.0MeV –4.5 First measurement arxiv:1205.6351 PRL LQCD pNRQCD b(2S) Belle 4.2w/ syst In agreement with theory (2S) = 4 8 MeV, < 24MeV @ 90% C.L. expect 4MeV Branching fractions Expectations BF[hb(1P) b(1S) ] = 49.25.7+5.6 % BF[hb(2P) b(1S) ] = 22.33.8+3.1 % BF[hb(2P) b(2S) ] = 47.510.5+6.8 % 41% 13% 19% –3.3 Godfrey Rosner PRD66,014012(2002) –3.3 –7.7 c.f. BESIII BF[hc(1P) c(1S) ] = 54.38.5 % 39%
_ Anomalies in (5S)(bb)+– transitions (11020) Belle: PRL100, 112001 (2008) 100 11.00 [(5S) (1,2,3S) +–]>> [(4,3,2S) (1S) +–] (10860) _ +– Rescattering of on-shell B(*)B(*) ? 260 10.75 (4S) 2M(B) 2 330 10.50 (3S) Mass, GeV/c2 hb(2P) 430 10.25 1 190 (2S) Belle: PRL108, 032001 (2012) b(2S) 10.00 hb(1P) 290 6 9.75 partial (keV) expect suppression QCD/mb (1S) 9.50 (5S) hb(1,2P) +– are not suppressed b(1S) spin-flip Heavy Quark Symmetry JPC= 0-+1--1-+ hb production mechanism? Study resonant structure in hb(mP)+–
Resonant substructure of (5S) hb(1P)+- phase-space MC Fit function _ ~BB* threshold _ _ ~B*B* threshold P(hb) = P(5S) – P(+-) M(hb+) = MM(-) measure (5S)hb yield in bins of MM() data PHSP combine PRL108,122001(2012) Results M1 = MeV/c2 Significance 1 = MeV a = 18 (16 w/ syst) M2 = MeV/c2 non-res. amplitude ~0 2 = MeV = degree
Resonant substructure of (5S) hb(2P)+- phase-space MC data PHSP combine hb(1P)+- hb(2P)+- MeV/c2 PRL108,122001(2012) MeV MeV/c2 M1 = MeV/c2 c o n s i s t e n t Significance MeV 1 = MeV 6.7 (5.6 w/ syst) M2 = MeV/c2 = degree degree 2 = MeV
Exclusive (5S) ->(nS) p+p- (5S) (nS)+- (n = 1,2,3) (nS) +- (3S) (2S) (1S) reflections
_ Resonant structure of (5S)→(bb)+– (5S) hb(1P)+- (5S) hb(2P)+- Two peaks are observed in all modes! no non-res. contribution phsp Belle: PRL108, 232001 (2012) phsp Zb(10610) and Zb(10650) should be multiquark states Dalitz plot analysis M[ hb(1P) π] M[ hb(2P) π] (5S) (2S)+- (5S) (1S)+- (5S) (3S)+- note different scales
Summary of Zb parameters Average over 5 channels M1 = 10607.22.0 MeV 1 = 18.42.4 MeV M2 = 10652.21.5 MeV 2 = 11.5 2.2 MeV M1 – (MB+MB*) = + 2.6 2.1 MeV M2 – 2MB* = + 1.8 1.7 MeV Zb(10610) yield ~ Zb(10650) yield in every channel Relative phases: 0o for and 180o for hb
Heavy quark structure in Zb A.B.,A.Garmash,A.Milstein,R.Mizuk,M.Voloshin PRD84 054010 (arXiv:1105.4473) Wave func. at large distance – B(*)B* 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 –”– • JP 1+ quantum numbers Predicts Other Possible Explanations • Coupled channel resonances (I.V.Danilkin et al, arXiv:1106.1552) • Cusp (D.Bugg Europhys.Lett.96 (2011),arXiv:1105.5492) • Tetraquark (M.Karliner, H.Lipkin, arXiv:0802.0649)
(5S)→(2S)π+π–: JP Results (2S)π+πData Toy MC with various JP JP = 1+ JP = 1- JP = 2+ JP = 2-
Heavy quark structure in Zb A.B.,A.Garmash,A.Milstein,R.Mizuk,M.Voloshin PRD84 054010 (arXiv:1105.4473) Wave func. at large distance – B(*)B* 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 –”– • JP 1+ quantum numbers • Dominant decays to B(*)B* Predicts
(5S)→B*B(*)π: B Selection 2-body (5S) decays B*B* Data (B signal) BB* BB Data (B side bands) 3-body (5S) -> B(*)B(*)π decays & rad. return to (4S): P(B)<0.9 GeV/c
(5S)→B*B(*)π: Data MC: B*Bπ Data BB*π B*B*π MC: B*B*π (shifted by 45MeV) Red histogram – right sign Bπ combinations; Hatched histogram – wrong sign Bπ combinations; Solid line – fit to right sign data. Belle PRELIMINARY Fit yields: N(BBπ) = 0.3 ± 14 N(BB*π) = 184 ± 19 (9.3σ) N(B*B*π) = 82 ± 11 (5.7σ)
(5S)→B*B(*)π: Signal Region Zb(10610) BB*π B*B*π Zb(10650) 8 6.8 Zb(10610) + Zb(10650) Zb(10650) alone PhSp Zb(10610)+ PhSp PhSp Zb(10650)+ PhSp Zb(10610) + Zb(10650) + PhSp Belle PRELIMINARY points – right sign Bπ combinations (data); lines – fit to data with various models (times PHSP, convolved with resolution function = Gaussian with σ=6MeV). hatched histogram – background component B*B*π signal is well fit to just Zb(10650) signal alone BB*π data fits (almost) equally well to a sum of Zb(10610) and Zb(10650) or to a sum of Zb(10610) and non-resonant.
(5S)→B*B(*)π: Results Branching fractions of (10680) decays (including neutral modes): BBp < 0.60% (90%CL) BB*p = 4.25 ± 0.44 ± 0.69% B*B*p = 2.12 ± 0.29 ± 0.36% Assuming Zb decays are saturated by the already observed (nS)π, hb(mP)π and B(*)B* channels, one can calculate complete table of relative branching fractions: Belle PRELIMINARY B(*)B* channels dominate Zb decays !
Heavy quark structure in Zb A.B.,A.Garmash,A.Milstein,R.Mizuk,M.Voloshin PRD84 054010 (arXiv:1105.4473) Wave func. at large distance – B(*)B* 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 –”– • JPC 1+- quantum numbers • Dominant decays to B(*)B* • Similar states in Charm Predicts
Heavy quark structure in Zb A.B.,A.Garmash,A.Milstein,R.Mizuk,M.Voloshin PRD84 054010 (arXiv:1105.4473) Wave func. at large distance – B(*)B* 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 –”– • JPC 1+- quantum numbers • Dominant decays to B(*)B* • Similar states in Charm • More bottomonium-like states Predicts
12GeV M.Voloshin PRD84(2011) 031502 U(?S) 11.5GeV U(6S) h U(5S) r w g r r p w g B*B* w Up hbphbr Ur Ur hbp Uh hbw Uw hbh Uw g BB* g Ur Uw BB Wb1 Xb Wb2 Wb0 Zb 0-(1+) IG(JP) 1+(1+) 0+(0+) 1-(0+) 0+(1+) 1-(1+) 0+(2+) 1-(2+) 0-(1-)
SuperKEKB Belle II e+ New IR New superconducting /permanent final focusing quads near theIP New beam pipe & bellows Replace short dipoles with longer ones (LER) e- Add / modify RF systems for higher beam current Low emittance positrons to inject Redesign the lattices of HER & LER to squeeze the emittance Positron source Damping ring Low emittance gun Low emittance electrons to inject New positron target / capture section TiN-coated beam pipe with antechambers To aim ×40 luminosity
Summary The first exotic bottomonium-like Zb+states were discovered in decays to (1S)+, (2S)+, (3S)+,hb(1P)+,hb(2P)+ Spin parity of Zbsis 1+ Zbs mainly decay to BB* and B*B*final states Zb(10610) dominantly decays to BB*, but Zb(10650) to B*B* Decay fraction of Zb(10650) to BB* is currently not statistically significant, but at least less than to B*B* Phase space of Y(5S)->B(*)B*p is tiny, relative motion B(*)B*is small, which is favorable to the formation of the molecular type states Y(5S) [and possible Y(6S)] is ideal factory of molecular states In heavy quark limit we can expect more molecular-like states in vicinity of the BB, BB* and B*B*. To study the new states we need the energy up to 12GeV
We enter the new region – Physics of Highly Excited Quarkonium or/and Chemistry of Heavy Flavor We can expect much more from Super B factory
Variables definition φ ψ π2 π1 π2 μ2 μ2 π2 μ2 ϑhel ϑ Zb Zb (nS) e+ π1 e- (5S) Zb μ1 (nS) μ1 μ1
The X(3872) in BK p+p-J/y discovered by Belle (140/fb) PRL 91, 262001 (2003) y’p+p-J/y X(3872)p+p-J/y M(ppJ/y) – M(J/y)
First measurements (5S) 121.4 fb-1 (6S) 5 fb-1 Measurements of the (nS)p+p-, hbp+p- cross-section vs energy Zb’s cross-section Radiative and hadronic transitions 44
Branching Fractions (nS)π+π- production cross section (corrected for the ISR) at sqrt(s) = 10.865 GeV: σ(e+e-→ (1S) π+π- = [2.27 ±0.12(stat.) ±0.09(syst.)] pb σ(e+e-→ (2S) π+π- = [4.07 ±0.16(stat.) ±0.45(syst.)] pb σ(e+e-→ (3S) π+π- = [1.46 ±0.09(stat.) ±0.16(syst.)] pb Fractions of individual sub-modes: Belle PRELIMINARY
(11020) 11.00 (10860) 10.75 (4S) 2M(B) 10.50 (3S) b(3S) b(2P) hb(2P) 10.25 Mass, GeV/c2 (2S) b(2S) b(1P) 10.00 hb(1P) Large production rate: N b(2S) 0.2 N b1 factor 30 9.75 c.f.(’c(2S)) = 0.007 (’c1) “Signal” of exclusively reconstructed b(2S) BESIII arxiv:1205.5103 PRL (1S) 9.50 b(1S) (0,1,2)++ - - -- JPC = 0+ 1 1 + CLEO data Dobbs, Metreveli, Seth, Tomaradze, Xiao, PRL 109 (2012) 082001 _ e+e- (2S) b(2S) , b(2S) 4,6,8,10 , K, p/p (26 channels) 4.6 Issues Bg from final state radiation can mimic signale.g. (2S) K+K- n(+-) FSR power law tail instead of exponential not discussed hadrons Large MHF(2S) CLEO48.72.7 MeV Belle strong disagreement with theory 5σ 24.3 +4.0 MeV agrees with theory –4.5 –4.5 Reported excess is unlikely to be the b(2S) signal
(11020) 11.00 (10860) 10.75 (4S) 2M(B) 10.50 (3S) b(3S) b(2P) hb(2P) 10.25 Mass, GeV/c2 (2S) b(2S) b(1P) 10.00 hb(1P) Large production rate: N b(2S) 0.2 N b1 factor 30 9.75 c.f.(’c(2S)) = 0.007 (’c1) “Signal” of exclusively reconstructed b(2S) BESIII arxiv:1205.5103 PRL (1S) 9.50 b(1S) (0,1,2)++ - - -- JPC = 0+ 1 1 + CLEO data Dobbs, Metreveli, Seth, Tomaradze, Xiao, PRL 109 (2012) 082001 _ e+e- (2S) b(2S) , b(2S) 4,6,8,10 , K, p/p (26 channels) 4.6 Issues Bg from final state radiation can mimic signale.g. (2S) K+K- n(+-) FSR power law tail instead of exponential not discussed hadrons Large MHF(2S) CLEO48.72.7 MeV Belle strong disagreement with theory 5σ 24.3 +4.0 MeV agrees with theory –4.5 –4.5 Reported excess is unlikely to be the b(2S) signal
Tetraquark? Ying Cui, Xiao-lin Chen, Wei-Zhen Deng, Shi-Lin Zhu, High Energy Phys.Nucl.Phys.31:7-13, 2007 (hep-ph/0607226) M ~ 10.2 – 10.3 GeV M ~ 10.5 – 10.8 GeV Tao Guo, Lu Cao, Ming-Zhen Zhou, Hong Chen, (1106.2284) M ~ 9.4, 11 GeV M.Karliner, H.Lipkin, (0802.0649)
Coupled channel resonance? I.V.Danilkin, V.D.Orlovsky, Yu.Simonov arXiv:1106.1552 No interaction between B(*)B* or is needed to form resonance No other resonances predicted B(*)B* interaction switched on individual mass in every channel?
Cusp? D.Bugg Europhys.Lett.96 (2011) (arXiv:1105.5492) Line-shape Amplitude Not a resonance