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Exotic mesons with hidden bottom near thresholds

Exotic mesons with hidden bottom near thresholds. arXiv:1111.2921 [ hep-ph ] accep ted in PRD. D2 S. Ohkoda (RCNP) In collaboration with Y. Yamaguchi (RCNP) S. Yasui (KEK) K. Sudoh ( Nishogakusha ) A. Hosaka (RCNP). Contents.

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Exotic mesons with hidden bottom near thresholds

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  1. Exotic mesons with hidden bottom near thresholds arXiv:1111.2921[hep-ph] accepted in PRD D2 S. Ohkoda (RCNP) In collaboration with Y. Yamaguchi (RCNP) S. Yasui (KEK) K. Sudoh (Nishogakusha) A. Hosaka (RCNP) Heavy quark hadrons

  2. Contents • Introduction • What is exotic hadrons? • Zb(10610) and Zb(10650) • Potential model • Formalism • Numerical results • Channel coupling effects • Summary Heavy quark hadrons

  3. Motivation Everything are not forbidden “… while mesons are made out of (qq), (qqqq), etc.” Gell-Mann, Phys. Lett. 8, 214 (1964) Heavy quark hadrons

  4. charmonium Y(4630) • Cornell potential well explains the charmonium spectrum Z(4430) Y(4350) s1 quarkoniumcc + exoticstates Z(4250) Y(4260) C C X(4160) Y(4140) L s2 Z(4050) Y(4008) Y(3940) X(3940) X(3872) quarkoniumcc ? Eichten in QWG 2008 Nara Heavy quark hadrons

  5. Bottomonium spectrum 5s Zb(10650) Zb(10610) BB threshold Charm2012

  6. Exotic hadron properties Exotic hadrons do not fit into the conventional qq quark model • Exotic quantum numbers I(JPC) = 0(0+-), 0(0--), 0(1-+), 0(2+-)… and I=1 states. Ex) Z(4430)+, Zb(10610)+, Zb(10650)+ • Decay width is quite narrow Some exotic hadrons have the “narrow” decay width. Open charm decays seem to be suppressed. Ex) Γ(Y(4140)) = 11.6 MeV • Unexpected decay channel and ratio Isospin breaking? Exotic spin structure? • Mass position do not fit into usual quark model prediction Heavy quark hadrons

  7. Observation of Zb(10610) and Zb(10650) PRL 108, 122001 (2012) By belle collaboaltion Heavy quark hadrons

  8. Υ(5S) has anomalously high rates toΥ(1S), Υ(2S) and Υ(3S) What is the origin ? Heavy quark hadrons

  9. Intermediate states appear in Υ(5S) → Υ(nP) π+ π− PRL 108, 122001 (2012) Heavy quark hadrons

  10. Look for hb and hb(2P) in Υ(5S) → π+π− + anything Heavy quark hadrons

  11. Exotic decay ratios for hb(1P) = for hb(2P) The process with spin-flip is not suppressed ! Υ(5S) → hb(mP) π+π-decay is exotic Heavy quark hadrons

  12. Resonant structure of Υ(5S) → hb(mP) π+π− 〜BB* threshold 〜B*B* threshold Resonance parameters are consistent for hb(1P)ππ and hb(1P)ππ Almost allhb(mP) are produced through Υ(5S) →Zb π → hb ππ Heavy quark hadrons

  13. Mass and width in each measurement Zb(10650) Zb(10610) M = 10652.2 ± 1.7 MeV Γ = 11.5 ± 2.2 MeV M = 10607.2 ± 2.0 MeV Γ = 18.4 ± 2.4 MeV Heavy quark hadrons

  14. Exotic mesons with hidden bottom near thresholds arXiv:1111.2921[hep-ph] Submitted in PRD Heavy quark hadrons

  15. Zb(10610) and Zb(10650) By Belle Collaboration arXiv:1110.2251 Decay processes Υ(5S)Zb π Υ(nS)ππ Υ(5S) Zb πhb(mP)ππ n = 1,2,3 m= 1,2 M(Zb(10610))= 10607.2 ±2.4 MeV M(Zb(10650))= 10652.2 ±1.5 MeV Υ(5S) 10610, 10650 Properties • Exotic quantum numbers • IG (JP) = 1+(1+) • Exotic decay ratios • Γ(Zb → Υ(nS)π) ≈ Γ(Zb → hb(mP)π) • “Exotic twin” resonances • Δm = m(Zb(10650))-m(Zb(10610)) • ≈ 45MeV ± ± ± ±x Υ(nS), n=1,2,3 hb(mP), m=1,2 Zb’s are good candidates of molecule states Heavy quark hadrons

  16. The puzzle of Zb Decay width ϒ(5S) Zb+ π- ϒ(nS) π+π- ϒ(5S) Zb+ π- hb(kP) π+π- No spin flip Spin flip ! process with spin flip should be suppressed because of large mass of b quark In practice, these process have almost the same probability Sl : spin of light degree of freedom hb π Υ π If Zbis meson molecular states, spin flip problem is solved. A.E. Bondar et al. PRD(2011) Heavy quark hadrons

  17. Do molecule states exist? B(*) (D) B(*) (D) π, ρ, ω,… • Can the OBEP bind mesons in heavy quark sector? • Could such states explain the exotic states which do not fit into the conventional qq quark model? Heavy quark hadrons

  18. Why are molecular states studied in heavy quark sectors? • The kinetic term of Hamiltonian is suppressed Because the reduced mass is larger in heavy mesons Ex) two body systems B and B* are degenerate thanks to HQS The interaction of heavy quark spin is suppressed in heavy quark sector mK∗ − mK ~ 400 MeV mD∗ − mD~ 140 MeV -> The effects of channel-couplings becomes larger mB∗ − mB~ 45 MeV Heavy quark hadrons

  19. Effect of mass degeneracy N P N P 3S1 1S0 π π 3D1 5D0 P* P* π π 1S0 3S1 N N P P P=D,B Heavy quark hadrons

  20. Coupling strength HQS vs SU(4) gDD*πcoupling is very strong in heavy quark sector ! Seminor in Nagoya Univ.

  21. BB Components Heavy quark hadrons

  22. Model setup Lagrangians for heavy mesons Heavy meson field P = D or B P* = D* or B* (D*→ Dπ, radiative decay, loptonicdecay of B) R. Casalbuoni et al, Phys. Rep. 281, 145 (1997) Heavy quark hadrons

  23. Model setup Cutoff • We employ monopole-type Form factor for each vertex • The cutoff ΛN is determined from deuteron • ΛP is determined by the ratio of the size Heavy quark hadrons

  24. Model setup the coupled channel potential Ex) IG (JPC) = 1+(1+-) : Zb,Zb’ Hamiltonian We solve numerically the Schrödinger equation Heavy quark hadrons

  25. We solve numerically the coupled-channel Schrödinger equation • We found no DD bound and resonance states • with exotic quantum numbers • But several BB bound and resonance states are obtained • There is novel correspondence of BB states and Zb Heavy quark hadrons

  26. 3 results Numerical results Resonance state Ere =50.4MeV B*B* Z’bexperiment (10650) Remarks 45MeV • We find the twin states in 1+(1+-)near the BB* and B*B* threshold. These states would be interpreted as Zb’s. • OPEP is dominant in this system. • Molecular states in IG (JP) = 1+(1+) are unique property in bottom quark sector. Zbexperiment BB* (10604) BB* bound state EB = -8.5 MeV Heavy quark hadrons • We find the twin states in 1+(1+-)near the BB* and B*B* threshold. These states would be interpreted as Zb’s. • In other channels we further predict the BB bound and resonant states. • BB states have decay channels of a quarkonium and a light flavor meson. • OPEP is dominant in this system. • In charm sector, our model does not predict any bound or resonant states which have exotic quantum numbers. • We find the twin states in 1+(1+-)near the BB* and B*B* threshold. These states would be interpreted as Zb’s. • In other channels we further predict the BB bound and resonant states. • BB states have decay channels of a quarkonium and a light flavor meson. • OPEP is dominant in this system. • In charm sector, our model does not predict any bound or resonant states which have exotic quantum numbers. • We find the twin states in 1+(1+-)near the BB* and B*B* threshold. These states would be interpreted as Zb’s. • In other channels we further predict the BB bound and resonant states. • BB states have decay channels of a quarkonium and a light flavor meson. • OPEP is dominant in this system. • In charm sector, our model does not predict any bound or resonant states which have exotic quantum numbers. • We find the twin states in 1+(1+-)near the BB* and B*B* threshold. These states would be interpreted as Zb’s. • In other channels we further predict the BB bound and resonant states. • BB states have decay channels of a quarkonium and a light flavor meson. • OPEP is dominant in this system. • In charm sector, our model does not predict any bound or resonant states which have exotic quantum numbers.

  27. results The BB bound and resonance states B*B* (10650) 10655 10649 Zb(10652) 10622 10621 10617 Zb(10607) 10606 10602 BB* (10604) 10594 10596 10566 BB (10559) IG(JPC) 1+(0--) 1+(1--) 1-(2++) 1+(1+-) 1-(1++) 1+(2--) 0+(1-+) Heavy quark hadrons

  28. Decay channel 0-(1--) ϒ(5S) (10860) π S-wave B*B* (10650) How to produce? π P-wave γ Υπ, hbπ Υπ, ηbπ Υρ, Χbπ BB* hbπ, ηbρ,Υπ (10604) Υπ, ηbπ Υρ, Χbπ Υπ, hbπ Υπ, ηbρ How to decay? BB (10559) hbπ, ηbρ,Υπ IG(JPC) 1+(0--) 1+(1--) 1-(2++) 1+(1+-) 1-(1++) 1+(2--) Heavy quark hadrons

  29. 3 results Numerical results Resonance state Ere =50.4MeV B*B* Z’bexperiment (10650) Remarks 45MeV • Observed Zb’s are resonance states. • But our model predict BB* bound state. • What will happen if our prediction includes channel coupling effect ? Zbexperiment BB* (10604) BB* bound state EB = -8.5 MeV Heavy quark hadrons • We find the twin states in 1+(1+-)near the BB* and B*B* threshold. These states would be interpreted as Zb’s. • In other channels we further predict the BB bound and resonant states. • BB states have decay channels of a quarkonium and a light flavor meson. • OPEP is dominant in this system. • In charm sector, our model does not predict any bound or resonant states which have exotic quantum numbers. • We find the twin states in 1+(1+-)near the BB* and B*B* threshold. These states would be interpreted as Zb’s. • In other channels we further predict the BB bound and resonant states. • BB states have decay channels of a quarkonium and a light flavor meson. • OPEP is dominant in this system. • In charm sector, our model does not predict any bound or resonant states which have exotic quantum numbers. • We find the twin states in 1+(1+-)near the BB* and B*B* threshold. These states would be interpreted as Zb’s. • In other channels we further predict the BB bound and resonant states. • BB states have decay channels of a quarkonium and a light flavor meson. • OPEP is dominant in this system. • In charm sector, our model does not predict any bound or resonant states which have exotic quantum numbers. • We find the twin states in 1+(1+-)near the BB* and B*B* threshold. These states would be interpreted as Zb’s. • In other channels we further predict the BB bound and resonant states. • BB states have decay channels of a quarkonium and a light flavor meson. • OPEP is dominant in this system. • In charm sector, our model does not predict any bound or resonant states which have exotic quantum numbers.

  30. Effects of the coupling to decay channels Loop function Imaginary part of loop function Table: Various coupling constants g = gΥ, ghb and the mass shifts δM of Zb . Λ=600 MeV Mass shift Total mass shift is 2.4 MeV. Effects of channel coupling are repulsive. Heavy quark hadrons Υ, hb Zb π

  31. results Numerical results Remarks • Channel coupling effects push up BB* bound state to 6.1MeV. • If we use Λ=520 MeV, BB* bound state corresponds the mass position of Zb. Resonance state Ere =50.4MeV B*B* Z’bexperiment (10650) ϒ(1S) π 15 Γ 45MeV 10 5 Zbexperiment BB* Mth (10604) 6 BB* bound state δM 2 EB = -6.1 MeV Mth Push up Heavy quark hadrons • We find the twin states in 1+(1+-)near the BB* and B*B* threshold. These states would be interpreted as Zb’s. • In other channels we further predict the BB bound and resonant states. • BB states have decay channels of a quarkonium and a light flavor meson. • OPEP is dominant in this system. • In charm sector, our model does not predict any bound or resonant states which have exotic quantum numbers. • We find the twin states in 1+(1+-)near the BB* and B*B* threshold. These states would be interpreted as Zb’s. • In other channels we further predict the BB bound and resonant states. • BB states have decay channels of a quarkonium and a light flavor meson. • OPEP is dominant in this system. • In charm sector, our model does not predict any bound or resonant states which have exotic quantum numbers. • We find the twin states in 1+(1+-)near the BB* and B*B* threshold. These states would be interpreted as Zb’s. • In other channels we further predict the BB bound and resonant states. • BB states have decay channels of a quarkonium and a light flavor meson. • OPEP is dominant in this system. • In charm sector, our model does not predict any bound or resonant states which have exotic quantum numbers. • We find the twin states in 1+(1+-)near the BB* and B*B* threshold. These states would be interpreted as Zb’s. • In other channels we further predict the BB bound and resonant states. • BB states have decay channels of a quarkonium and a light flavor meson. • OPEP is dominant in this system. • In charm sector, our model does not predict any bound or resonant states which have exotic quantum numbers.

  32. Summary • We have systematically studied the possibility of the BB bound and resonant states having exotic quantum numbers. • IG(JPC)=1+(1+-) states have a bound state with binding energy 8.5 MeV, and a resonant state with the resonance energy 50.4 MeV and the decay width 15.1 MeV. The twin resonances of Zb’s can be interpreted as the BB molecular type states. • The otherpossible BB states are predicted. • The channel mixing plays an important role. • One pion exchange potential is dominant. • Various exotic states would be observed around the thresholds from Υ(5S) decays in accelerator facilities such as Belle. Heavy quark hadrons

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