Charged bottomonium-like statCharged bottomonium-like states Zes Zbb(10610) and Z(10610) and Zbb(10650) (10650)

Xiang LiuXiang Liuxiangliu@lzu.edu.cn

Lanzhou UniversityLanzhou University

·

The Fifth Asia-Pacific Conference on Few-Body Problems in Physics

22-26 August 2011, Seoul, Republic of Korea

Xiang Liu @ LZU 2

OutlineOutline

• ExperimentExperiment ZZbb(10610)(10610) and and ZZbb(10650)(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

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Charmonium-like states XYZCharmonium-like states XYZ

In the past seven years, experiments reported many charmonium-like In the past seven years, experiments reported many charmonium-like states X,Y, Z. states X,Y, Z. BaBar+Belle+CLEO+CDFBaBar+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 presentHot topic in hadron physics at present..

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Experiment status of two charged ZbExperiment status of two charged Zb

Belle CollaborationBelle Collaboration

arXiv:1105.4583arXiv:1105.4583

ZZbb(10610)(10610)

ZZbb(10650)(10650)

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Charged bottomonium-like structuresCharged bottomonium-like structures

Close to the B*B or B*B* thresholdClose to the B*B or B*B* threshold

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Dipion hidden-bottom decays of Y(5S)Dipion hidden-bottom decays of Y(5S) A. BONDAR Talk in FPCP2011A. BONDAR Talk in FPCP2011

Meng&Chao, PRD77, 074003 (2008)

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Ali et al., PRL104, 162001Ali et al., PRL104, 162001

Tetraquark explanation to Y(10870)Tetraquark explanation to Y(10870)

Chen, He, Li,Chen, He, Li, Xiang Liu, Xiang Liu, arXiv:arXiv: 1105.16721105.1672

Indicate the Indicate the mistake in mistake in Ali’s workAli’s work

Propose Propose interference interference

effecteffect

New New puzzle!puzzle!

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Zb structues and New PuzzleZb structues and New Puzzle

Chen, Chen, Xiang LiuXiang Liu, Zhu,, Zhu, arXiv:arXiv: 1105.51931105.5193

Two newly observed Two newly observed ZZbb structure structuress play play important roleimportant role to solve “ to solve “NNew puzzleew puzzle” in ” in Y(5S)Y(5S)Y(2S)Y(2S)ππ++ππ- -

decaydecay

Question:Question: what iswhat is the source the source to generateto generate Zb(10610) Zb(10610) andand

Zb(10650)? Zb(10650)?

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• 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:1105.4473Zhang, Huang, arXiv:1105.5472 QCD sum ruleVoloshin, arXiv:1105.5829 Radiative decaysSun, He, Xiang Liu, Luo, Zhu, arXiv:1106.2968, accepted by PRD

One-Boson-exchange model

• Tetraquark stateTetraquark state

Yang, Ping, Deng, Zong, arXiv:1105.5935Guo, Cao, Zhou, Chen, arXiv:1106.2284

Theoretical explanation - exotic strucutesTheoretical explanation - exotic strucutes

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Sun, He, Xiang Liu, Luo, Zhu, arXiv:1106.2968, accepted by PRD

One-Boson-exchange modelOne-Boson-exchange model

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S-wave and D-wave contributions between B and B* mesons

The effective potential:The effective potential:

Zb(10610Zb(10610)

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Zb(10650Zb(10650)

The effective potential:The effective potential:

S-wave and D-wave interaction between B* S-wave and D-wave interaction between B* and B*and B*

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Sun, He, Xiang Liu, Luo, Zhu, arXiv:1106.2968, accepted by PRD

Both Zb(10610) and Zb(10650) can be explained as BB* Both Zb(10610) and Zb(10650) can be explained as BB* and B*B* molecular states. and B*B* molecular states.

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Initial Single Pion Emission (ISPE) mechaInitial Single Pion Emission (ISPE) mechanismnism

D.Y. Chen,D.Y. Chen, Xiang Liu Xiang Liu, arXiv:1106.3798 [hep-ph], arXiv:1106.3798 [hep-ph]

First propose a First propose a new decay mechanismnew decay mechanism existing in Y(5S) decayexisting in Y(5S) decay

the ISPE mechanismthe ISPE mechanismThe emitted pion with The emitted pion with continuous enercontinuous energy distributiongy distribution

B* and B* with B* and B* with low momentumlow momentum

EasilyEasily interacte with each other interacte with each other

B*B*B*B*Y(nS)Y(nS)ππ

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B*B*

BB*

BB

Exp

Kitty head!Kitty head!

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BB* BBB*B*

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Chen, Chen, Xiang LiuXiang Liu, Zhu,, Zhu, arXiv:arXiv: 1105.51931105.5193

An underlying mechanism An underlying mechanism without introducing exotic without introducing exotic

explanation!explanation!

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More predictionsMore predictions

If the If the ISPE mechanismISPE mechanism is a is a universaluniversal mechanism in heavy quarkoni mechanism in heavy quarkonium dipion decays, we naturally extend the ISPE mechanism to studum dipion decays, we naturally extend the ISPE mechanism to stud

y the y the hidden-charm dipionhidden-charm dipion decays of decays of higher charmoniahigher charmonia

D.Y. Chen,D.Y. Chen, Xiang Liu Xiang Liu, , Phys.Rev.D84, 034032 (2011)Phys.Rev.D84, 034032 (2011)

Higher charmoniaHigher charmonia

ΨΨ(4040),(4040),ΨΨ(4160),(4160),ΨΨ(4415)(4415)

Charmonium-like stateCharmonium-like state

Y(4260)Y(4260)

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BESIIIBESIII

Belle&BaBarBelle&BaBar

Belle IIBelle II

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CLEO-c, PRL107, 041803 (2011)

D.Y. Chen,D.Y. Chen, Xiang Liu Xiang Liu, , Phys.Rev.D84, 034032 (2011)Phys.Rev.D84, 034032 (2011)

Xiang Liu @ LZU 21

SummarySummary• Observation of Zb(10610) and Zb(10650) • Exotic structureExotic structure & production mechanismproduction mechanism• Y(5S) Y(5S) dipion hidden-bottomdipion hidden-bottom decays decays• The ISPEISPE mechanism ZZbb(10610) and (10610) and ZZbb(10(10

650)650)• Predict their Predict their charmonium analoguescharmonium analogues Two charged structures close to DD* and D*D* tTwo charged structures close to DD* and D*D* t

hresholds hresholds BESIII Belle BaBar Belle II SuperBBESIII Belle BaBar Belle II SuperB

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Thank you for Thank you for your attention! your attention!