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Recent results of charmonium decaying into baryons at BESIII

Recent results of charmonium decaying into baryons at BESIII. Xu Xinping 1,2 ( 徐新平 ) on behalf of the BESIII Collaboration 1.Depart. Physics & Astronomy, Seoul National University 2. Soochow University, Suzhou 215006, P.R. China. Out line:.

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Recent results of charmonium decaying into baryons at BESIII

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  1. Recent results of charmonium decaying into baryons at BESIII Xu Xinping1,2 (徐新平) on behalf of the BESIII Collaboration 1.Depart. Physics & Astronomy,Seoul National University 2.Soochow University, Suzhou 215006, P.R. China

  2. Out line: The BEPCII and BESIII detector The BESIII Collaboration Data samples at BESIII Physics Results 1. Large number of charmonium: J/ψ, χcJ , ηc, ψ(2S), 2. Baryons final states, pp̅ , nn̅, ΛΛ̅ , Σ0Σ̅ 0, Σ+Σ̅ -, p̅ K+Λ, etc Summary 2013 YongPyong Winter Conference

  3. BEPC II Storage ring: Double ring Beam energy: 1.0-2.3 GeV Design Luminosity: 1×1033 cm-2s-1 Optimum energy: 1.89 GeV Energy spread: 5.16 ×10-4 No. of bunches: 93 Bunch length: 1.5 cm Total current: 0.91 A Circumference： 237m RF SR RF IP

  4. The BESIII Detector SC magnet,1T Magnet yoke RPC TOF, 90ps Be beam pipe A total weight of 730t, ~40000 readout channels, data rate 6000Hz ~50Mb/s, ~1000 man*year, 30 M$ MDC, 120 mm CsI(Tl) calorimeter, 2.5 %@ 1 GeV

  5. BESIIICollaboration Europe (12) Germany: Univ. of Bochum, Univ. of Giessen, GSI Univ. of Johannes Gutenberg Helmholtz Ins. In Mainz Russia: JINR Dubna; BINP Novosibirsk Italy: Univ. of Torino，FrascatiLab Netherland：KVI/Univ. of Groningen Sweden: Uppsala Univ. Turkey: Turkey Accelerator Center US(6) Univ. of Hawaii Univ. of Washington Carnegie Mellon Univ. Univ. of Minnesota Univ. of Rochester Univ. of Indiana Korea (1) SeoulNat. Univ. Japan (1) Tokyo Univ. China(30) IHEP, CCAST, GUCAS, Shandong Univ., Univ. of Sci. and Tech. of China Zhejiang Univ., Huangshan Coll. Huazhong Normal Univ., Wuhan Univ. Zhengzhou Univ., Henan Normal Univ. Peking Univ., Tsinghua Univ. , Zhongshan Univ.,Nankai Univ. Shanxi Univ., Sichuan Univ., Univ. of South China Hunan Univ., Liaoning Univ. Nanjing Univ., Nanjing Normal Univ. Guangxi Normal Univ., Guangxi Univ. Suzhou Univ., Hangzhou Normal Univ. Lanzhou Univ., Henan Sci. and Tech. Univ. Hong Kong Univ., Hong Kong Chinese Univ. Pakistan (2) Univ.of Punjab COMSAT CIIT ~300 members 52 institutions from 11 countries

  6. 2009 • 106M (2S) (4 times of CLEOc) • 225M J/ (4 times of BESII) • 2010 • ~0.9 fb-1(3770) • 2011 • ~2.0 fb-1(3770) (3.5 times of CLEOc) • ~0.5 fb-1 @ 4.01 GeV • 2012 • ~0.4 billion (2S) • ~1 billion J/ • 515 pb-1 Y(4260) 40 times of the Cleoc; ~500 pb-1 Y(4360) The world Largest J/, (2S) , (3770) Y(4260)data samples. Data samples at BESIII experiment 2013 YongPyong Winter Conference

  7. Charmonium decays to Baryons BESIII have the largest charmonium data samples (J/, (2S)), including the transition charmonium states χcJ, ηc etc. Provide a good platform for precise measurement of charmonium decaying into baryonic final states 2013 YongPyong Winter Conference

  8. Recent results on Charmonium decaying into baryon final states Three body decay: J/ψ, ψ (2S)→ΛΛ̅ π0 /η ψ(2S)→p̅ K+Σ0 and χcJ→p̅ K+Λ ψ(2S)→pp̅ π0 BESIII Measurements: Two body decay: J/ψ→ΛΣ̅ 0 +c.c. χcJ → ΛΛ̅ , Σ0Σ̅ 0, Σ+Σ̅ - χcJ→ ΛΛ̅ π+π- J/ψ→pp̅ , nn̅ ηc → Σ+Σ̅ -, Ξ-Ξ̅ + 2013 YongPyong Winter Conference

  9. First Observation of J/ψ→Λ Σ̅ 0 +c.c. Motivation: isospin symmetry breaking decay Helpful to understand isospin breaking mechanisms in J/ψ→B8B̅ 8 BESIII Collaboration: PRD 86, 032008(2012) 2013 YongPyong Winter Conference

  10. J/ψ, ψ (2S)→ΛΛ̅ π0 /η Motivation: ΛΛ̅ π0 : isospin violating decay, first observation ΛΛ̅ η: isospin conserving decay BESIII Collaboration, arXiv:1211. arXiv:1211.4682 To be published in PRD 2013 YongPyong Winter Conference

  11. χcJ → ΛΛ̅ , Σ0Σ̅ 0, Σ+Σ̅ - • Motivation: Test color octet mechanism(COM) for the P-wave charmonia decay. High precision measurement is Important! BESIII Collab. PRD87, 032007(2013) 2013 YongPyong Winter Conference

  12. χcJ→ ΛΛ̅ π+π- • Data sample: 106M (2S) • ΛΛ̅ π+π- observedfor the first time • χcJ→ Σ̅ (1385)±Σ̅ (1385)-+ Observed for the first time BESIII Collaboration, PRD86, 052004 (2012) 2013 YongPyong Winter Conference

  13. J/ψ→pp̅ , nn̅ • Based on 225M J/ events • The most accurate measurements in the world • Angular parameter α: • BESIII Collaboration • PRD 86, 032014 (2012) 2013 YongPyong Winter Conference

  14. First observation of ηc → Σ+Σ̅ -, Ξ-Ξ̅ + • Data sample: 225M J/ events Compared with intermediate meson loop(IML) calculation • BESIII Collaboration, PRD 87, 012003 (2013) 2013 YongPyong Winter Conference

  15. ψ(2S)→p̅ K+Σ0 and χcJ→p̅ K+Λ • Data sample: 106M (2S) • ψ(2S)→p̅ K+Σ0 (first time observation) • There is an enhancement in the mass of p̅ Λ in the decay χcJ→p̅ K+Λ BESIII Collaboration, PRD87, 012007(2013) 2013 YongPyong Winter Conference

  16. ψ(2S)→pp̅ π0 • Use Partial Wave Analysis • Two new N* are observed BESIII Collaboration, PRL110, 022001(2013) 2013 YongPyong Winter Conference

  17. Summary Based on the largest charmonium data samples, the BESIII experiment obtained the most accurate results for charmonium decaying into baryonic final states. Some decays are measured for the first time, the others are measured with improved precision. J/ψ→ΛΣ̅ 0 +c.c. χcJ → ΛΛ̅ , Σ0Σ̅ 0, Σ+Σ̅ - χcJ→ ΛΛ̅ π+π- J/ψ→pp̅ , nn̅ ηc → Σ+Σ̅ -, Ξ-Ξ̅ + J/ψ, ψ (2S)→ΛΛ̅ π0 /η ψ(2S)→p̅ K+Σ0, χcJ→p̅ K+Λ, ψ(2S)→pp̅ π0 2013 YongPyong Winter Conference

  18. Thank you 2013 YongPyong Winter Conference

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