BES III future prospects in exotic spectroscopy Kai ZHU (IHEP) on behalf of BESIII 6th International conference on New Frontiers in Physics (ICNFP 2017) Workshop on exotic 17-29 August 2017, Kolymbari, Crete, Greece BEPCII: Beijing - II 北京 电子 - 正电子 对撞机 II

CMS energy：ퟐ. ퟎ ∼ ퟒ. ퟔ GeV； Luminosity: ퟏ × ퟏퟎퟑퟑ풄풎−ퟐ풔−ퟏ

MESON 2010 Kai Zhu 2 BESIII: BEijing Spectrometer III 北京 谱仪 III

Physics: light hadron, charmonium, charm, R-value & QCD, new physics

2017-4-19 XYZ at BESIII 3 “Normal” hadrons

• Exotic candidates

figures from arXiv:1403.1254, S. Olsen

2017-4-19 XYZ at BESIII 4 “Normal” hadrons

• Exotic candidates

figures from arXiv:1403.1254, S. Olsen

2017-4-19 XYZ at BESIII 5 2017-8-17 XYZ states at BESIII 6 2017-8-17 XYZ states at BESIII 7 2017-8-17 XYZ states at BESIII 8 2017-8-17 XYZ states at BESIII 9 2017-8-17 XYZ states at BESIII 10 2017-8-17 XYZ states at BESIII 11 2017-8-17 XYZ states at BESIII 12 2017-8-17 XYZ states at BESIII 13 2017-8-17 XYZ states at BESIII 14 2017-8-17 XYZ states at BESIII 15 2017-8-17 XYZ states at BESIII 16 2017-8-17 XYZ states at BESIII 17 2017-8-17 XYZ states at BESIII 18 2017-8-17 XYZ states at BESIII 19 2017-8-17 XYZ states at BESIII 20 2017-8-17 XYZ states at BESIII 21 2017-8-17 XYZ states at BESIII 22 2017-8-17 XYZ states at BESIII 23 2017-8-17 XYZ states at BESIII 24 2017-8-17 XYZ states at BESIII 25 2017-8-17 XYZ states at BESIII 26 2017-8-17 XYZ states at BESIII 27 2017-8-17 XYZ states at BESIII 28 2017-8-17 XYZ states at BESIII 29 2017-8-17 XYZ states at BESIII 30 2017-8-17 XYZ states at BESIII 31 2017-8-17 XYZ states at BESIII 32 2017-8-17 XYZ states at BESIII 33 2017-8-17 XYZ states at BESIII 34 2017-8-17 XYZ states at BESIII 35 2017-8-17 XYZ states at BESIII 36 2017-8-17 A charmoniumXYZ statesstate at BESIII 37 2017-8-17 XYZ states at BESIII 38 2017-8-17 XYZ states at BESIII 39 2017-8-17 XYZ states at BESIII 40 2017-8-17 XYZ states at BESIII 41 2017-8-17 XYZ states at BESIII 42 2017-8-17 XYZ states at BESIII 43 2017-8-17 XYZ states at BESIII 44 2017-8-17 XYZ states at BESIII 45 2017-8-17 XYZ states at BESIII 46 2017-8-17 XYZ states at BESIII 47 2017-8-17 XYZ states at BESIII 48 2017-8-17 XYZ states at BESIII 49 2017-8-17 XYZ states at BESIII 50 2017-8-17 XYZ states at BESIII 51 2017-8-17 XYZ states at BESIII 52 2017-8-17 XYZ states at BESIII 53 2017-8-17 XYZ states at BESIII 54 2017-8-17 XYZ states at BESIII 55 2017-8-17 XYZ states at BESIII 56 2017-8-17 XYZ states at BESIII 57 2017-8-17 XYZ states at BESIII 58 2017-8-17 XYZ states at BESIII 59 2017-8-17 XYZ states at BESIII 60 2017-8-17 XYZ states at BESIII 61 2017-8-17 XYZ states at BESIII 62 2017-8-17 XYZ states at BESIII 63 2017-8-17 XYZ states at BESIII 64 2017-8-17 XYZ states at BESIII 65 2017-8-17 XYZ states at BESIII 66 2017-8-17 XYZ states at BESIII 67 2017-8-17 XYZ states at BESIII 68 2017-8-17 XYZ states at BESIII 69 2017-8-17 XYZ states at BESIII 70 2017-8-17 XYZ states at BESIII 71 2017-8-17 XYZ states at BESIII 72 2017-8-17 XYZ states at BESIII 73 2017-8-17 XYZ states at BESIII 74 2017-8-17 XYZ states at BESIII 75 2017-8-17 XYZ states at BESIII 76 푒+푒− → 훾푋 3872 푌 4260 , 푌 4360 in + − 휋+휋−푋(3823) 푒 푒 → 휔휒푐퐽, 훾휒푐퐽 ′ 휂퐽/휓, 휂 퐽/휓, 휂ℎ푐 휋휋ℎ푐, 휋휋퐽/휓,훾휂푐

X Y

Z ±,0 ∗ 푍푐 3900 [휋퐽/휓,퐷퐷 ] No light hadron final states from ±,0 ∗ ∗ 푍푐 4240 [휋ℎ푐,퐷 퐷 ] XYZ decay is observed. Complex structured observed in 휋휓(3686).

2016-11-25 XYZ future at BESIII 77 Characteristics and trends in XYZ study at BESIII • Systematic

Ex. 휋0 휂 휂 ′ 푐 휂 퐽/휓 휋+휋− 훾 × 휒 휂휂 × 푐퐽 ℎ 휋+휋−휋0(휔) 푐 휓′ 휂휋휋 (∗) (∗) 휋0휋0 퐷 퐷 퐾+퐾− 휙

2017-8-17 XYZ states at BESIII 78 Characteristics and trends in XYZ study at BESIII • More amplitude analyses

2017-8-17 XYZ states at BESIII 79 XYZ Data: we already have ~12 fb−1

+ R-scan data sets

2017-8-17 XYZ states at BESIII 80 A big plan for XYZ

2017-8-17 XYZ states at BESIII 81 Further plan

• A few high statistics points (around 4.2, 4.3 4.4 GeV? ) – Primary focus: further study on 푍푐 states. • More high energy data (between 4.5 and 4.6 GeV? ) – Primary focus: line-shapes, Λ푐Λ푐 threshold, more phase space • > 4.6 GeV (the present upper energy of BEPCII) – R&D is on-going • Others (suggestions from theorists?) – Specific predictions are extremely welcome.

2017-8-17 XYZ states at BESIII 82 XYZ in the future at

• BESIII has observed/measured XYZ states. – From experiment side, 푍푐 3900 , 푍푐 4020 , and 푌(4260) are solidly established based on BESIII measurements. • Our knowledge of XYZ has been significantly improved. However, there are still many puzzles – One or two states when two resonances are close? – Complex structures are observed and difficult to describe. – Some expected states or decay modes have not been observed. – Nature of these states. – … • With more data and inputs from theorists, we will better understand these exotic states.

2016-11-25 XYZ future at BESIII 83 Thank you! 2017-8-17 XYZ states at BESIII 84