Charged bottomonium-like states Z b (10610) and Z b (10650) Xiang Liu Lanzhou University · The Fifth Asia-Pacific Conference on Few-Body Problems in Physics August 2011, Seoul, Republic of Korea

Xiang LZU2 Outline ExperimentZ b (10610) and Z b (10650)Experiment Z b (10610) and Z b (10650) Dipion hidden-bottom decays of Y(5S)Dipion hidden-bottom decays of Y(5S)  New puzzle!  New puzzle! Theorecital explanations—exotic structuresTheorecital explanations—exotic structures Initial Single Pion Emission (ISPE) mechanismInitial Single Pion Emission (ISPE) mechanism More predictionsMore predictions SummarySummary

Xiang LZU3 Charmonium-like states XYZ In the past seven years, experiments reported many charmonium-like states X,Y, Z. BaBar+Belle+CLEO+CDF In the past seven years, experiments reported many charmonium-like states X,Y, Z. BaBar+Belle+CLEO+CDF Stimulate theorist’s interest in revealying their underlying structures. Stimulate theorist’s interest in revealying their underlying structures. Hot topic in hadron physics at present. Hot topic in hadron physics at present.

Xiang LZU4 Experiment status of two charged Zb Belle Collaboration arXiv: Z b (10610) Z b (10650)

Xiang LZU5 Charged bottomonium-like structures Charged bottomonium-like structures Close to the B*B or B*B* threshold Close to the B*B or B*B* threshold

Xiang LZU6 Dipion hidden-bottom decays of Y(5S) A. BONDAR Talk in FPCP2011 Meng&Chao, PRD77, (2008)

Xiang LZU7 Ali et al., PRL104, Tetraquark explanation to Y(10870) Chen, He, Li, Xiang Liu, arXiv: Indicate the mistake in Ali’s work Propose interference effect New puzzle!

Xiang LZU8 Zb structues and New Puzzle Chen, Xiang Liu, Zhu, arXiv: Two newly observed Z b structures play important role to solve “New puzzle” in Y(5S)  Y(2S)π+π- decay Question: what is the source to generate Zb(10610) and Zb(10650)?

Xiang LZU9 S-wave BB* and B*B* molecular statesS-wave BB* and B*B* molecular states Liu, Xiang Liu,Deng, Zhu, EPJC56, 63 (2008) Xiang Liu, Luo, Liu, Zhu, EPJC61, 411 (2009) Bondar, Garmash, Milstein, Mizuk, Voloshin, arXvi: Zhang, Huang, arXiv: QCD sum rule Voloshin, arXiv: Radiative decays Sun, He, Xiang Liu, Luo, Zhu, arXiv: , accepted by PRD One-Boson-exchange model Tetraquark stateTetraquark state Yang, Ping, Deng, Zong, arXiv: Guo, Cao, Zhou, Chen, arXiv: Theoretical explanation - exotic strucutes

Xiang LZU10 Sun, He, Xiang Liu, Luo, Zhu, arXiv: , accepted by PRD One-Boson-exchange model

Xiang LZU11 S-wave and D-wave contributions between B and B* mesons The effective potential: Zb(10610 Zb(10610)

Xiang LZU12 Zb(10650 Zb(10650) The effective potential: S-wave and D-wave interaction between B* and B*

Xiang LZU13 Sun, He, Xiang Liu, Luo, Zhu, arXiv: , accepted by PRD Both Zb(10610) and Zb(10650) can be explained as BB* and B*B* molecular states.

Xiang LZU14 Initial Single Pion Emission (ISPE) mechanism D.Y. Chen, Xiang Liu, arXiv: [hep-ph] First propose a new decay mechanism existing in Y(5S) decay the ISPE mechanism The emitted pion with continuous energy distribution  B* and B* with low momentum  Easily interacte with each other  B*B*  Y(nS)π

Xiang LZU15 B*B* BB* BB Exp Kitty head!

Xiang LZU16 BB*BBB*B*

Xiang LZU17 Chen, Xiang Liu, Zhu, arXiv: An underlying mechanism without introducing exotic explanation!

Xiang LZU18 More predictions If the ISPE mechanism is a universal mechanism in heavy quarkonium dipion decays, we naturally extend the ISPE mechanism to study the hidden-charm dipion decays of higher charmonia D.Y. Chen, Xiang Liu, Phys.Rev.D84, (2011) Higher charmonia Ψ(4040),Ψ(4160),Ψ(4415) Charmonium-like state Y(4260)

Xiang LZU19 BESIII Belle&BaBar Belle II

Xiang LZU20 CLEO-c, PRL107, (2011) D.Y. Chen, Xiang Liu, Phys.Rev.D84, (2011)

Xiang LZU21 Summary Observation of Z b (10610) and Z b (10650) Exotic structureproduction mechanismExotic structure & production mechanism Y(5S) dipion hidden-bottom decaysY(5S) dipion hidden-bottom decays ISPE Z b (10610) and Z b (10650)The ISPE mechanism  Z b (10610) and Z b (10650) Predict their charmonium analoguesPredict their charmonium analogues Two charged structures close to DD* and D*D* thresholds Two charged structures close to DD* and D*D* thresholds BESIII Belle BaBar Belle II SuperB  BESIII Belle BaBar Belle II SuperB

Xiang LZU22 Thank you for your attention! Thank you for your attention!