1 / 41

Overview of BES physics

Overview of BES physics. Yifang Wang Institute of High Energy Physics. BES experiments. BESII. BESI Stared in late 80’s BESII Stared in late 90’s BESIII is starting now. Rich physics at tau-charm. ~ 150 papers on PRL, PRD, PLB. Before BES. Before BES. After BES. After BES.

lilac
Download Presentation

Overview of BES physics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Overview of BES physics Yifang Wang Institute of High Energy Physics

  2. BES experiments BESII • BESI Stared in late 80’s • BESII Stared in late 90’s • BESIII is starting now Rich physics at tau-charm ~ 150 papers on PRL, PRD, PLB

  3. Before BES Before BES After BES After BES R value and  excited states From PDG Significantly improved data quality in 2.0-5.0 GeV region,

  4. An enhancement near the ppbar threshold Observation of X(1835) J/ygpp 7.7 0 0.2 M(pp)-2mp (GeV/c2) • Phys. Rev. Lett., 91 (2003) 022001 Phys. Rev. Lett. Dec.31, 2005

  5. Phys. Rev. Lett. 97 (2006) 142002 Observation of a broad resonance in J/  K+K- 0 Background • X pole position: PWA analysis and parity conservation considerations yield: Too many 1--, Width is much broader than other mesons; multiquark state ?

  6. Observation of N(2050) N*(1520) N*(1535) N*(1650) N*(1675) N*(1680) N*(1440)? ? N(2050): 1/2+或 3/2+ N(1440): Phys. Rev. Lett. 97 （2006）062001

  7. Phys. Rev. Lett. 93, 112002 (2004) Observation of an anomalous enhancement near the threshold of mass spectrum BES II 3-body phase space For a S-wave BW fit: M = 2075 12  5 MeV Γ = 90  35  9 MeV

  8. BEPC upgrade: BEPCIIUnique physics opportunities • In a regime of transition between pQCD and non-pQCD • Can provide calibrations and tests of LQCD • Rich spectra of light hadrons for Quark model test and for searches of new hadrons • Rich gluonic matter production for QCD test • Near the production threshold of tau-charm: good for quantum correlation constraints • Complementary to LHC experiments

  9. Physics at BEPCII/BESIII • Precision measurement of CKM matrix elements • Precision test of Standard Model • Light hadron spectroscopy • Charmonium physics • Search for new physics/new particles hep-ex/0809.1869

  10. Light hadron spectroscopy 1010 J/y events is probably enough to pin down most of problems of light hadron spectroscopy • Baryon spectroscopy • Charmonium spectroscopy • Glueball searches • Search for non-qqbar states Spectrum of glueballs from LQCD

  11. Precision measurement of CKM----Branching rations of charm mesons • Vcd /Vcs: Leptonic and semi-leptonic decays • Vcb: Hadronic decays • Vtd /Vts: fD and fDs fromLeptonic decays • Vub: Form factors of semi-leptonic decays • Unitarity Test of CKM matrix

  12. Precision test of SM and Search for new Physics • DDbar mixing DDbar mixing in SM ~ 10 –3 -10 –10 DDbar mixing sensitive to “new physics” Our sensitivity : ~ 10-4 • Lepton universality • CP violation • Rare decays FCNC, Lepton no. violation, ...

  13. BEPC II Storage ring: Large angle, double-ring RF SR RF Beam energy: 1-2 GeV 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 SR mode: 0.25A @ 2.5 GeV IP

  14. Commissioning milestones Oct. 25-31, 2007: accumulation of electron/positron beams Nov. 18, 2007: first e+e- collision without BESIII detector Mar. 2008: Collision 500 mA × 500 mA, Lumi.: 1 ×1032 cm-2s-1 April 30,2008: Move BESIII to IP July 18, 2008: First event in BESIII

  15. The BESIII Detector SC magnet,1T Magnet yoke RPC TOF, 90ps Be beam pipe MDC, 130 mm CsI(Tl) calorimeter, 2.5 %@1 GeV

  16. BESIII collaboration Europe (5) GSI, Germany University of Bochum, Germany University of Giessen, Germany JINR, Dubna, Russia Univ. of Torino, Italy China (23) IHEP, CCAST, Univ. of Sci. and Tech. of China Shandong Univ., Zhejiang Univ. Huazhong Normal Univ., Wuhan Univ. Zhengzhou Univ., Henan Normal Univ. Peking Univ., Tsinghua Univ. , Zhongshan Univ.,Nankai Univ. Shanxi Univ., Sichuan Univ Hunan Univ., Liaoning Univ. Nanjing Univ., Nanjing Normal Univ. Guangxi Normal Univ., Guangxi Univ. Hong Univ., Hong Kong Chinese Univ. USA (6) Univ. of Hawaii, Univ. of Washington,Univ. of Minisolta, Carnegie Mellon Univ., RPI, Rochester Uni., Japan (1) Tokyo University

  17. Drift chamber Babar: ~110mm BELLE: ~130mm CLEO: ~110mm BESIII: ~130mm • To measure the momentum of charged particles by its bended curvature in a magnetic field • 7000 Signal wires: 25 mm gold-plated tungsten • 22000 Field wires: 110 mm Al • Gas: He + C3H8 (60/40) • Momentum resolution@1GeV:

  18. BESIII CsI(Tl) crystal calorimeter Babar: 2.67% @1GeV BELLE: 2.2% @1GeV CLEO: 2.2% @1GeV BESIII: 2.5%@1GeV • To measure the energy of electromagnetic particles • Barrel: 5280 crystals，Endcap: 960 crystals • Crystal: (5.2x 5.2 – 6.4 x 6.4) x 28cm3 • Readout: 13000 Photodiodes, 1cm2cm, • Energy range：20MeV – 2 GeV • position resolution: 6 mm @ 1GeV • Tiled angle: theta ~ 1-3o, phi ~ 1.5o

  19. PID: TOF system • Barrel: 2*88 BC408, 2.4 m long, 5cm thick • Endcap：2* 48 BC 408 • PMT: Hamamatzu R5942

  20. m system : RPC • 9 layer, 2000 m2 • Special bakelite plate w/o lineseed oil • 4cm strips, 10000 channels • Noise less than 0.1 Hz/cm2

  21. First cosmic-ray event • trigger+DAQ＋detector(MDC＋EMC＋TOF+MUON） • Trigger condition：cosmic-rays

  22. First collision event on July 19, 2008 13 M y’ events collected in 2008

  23. MDC calibration Eff.: ~ 98% Reso. 128 mm σP=12.0MeV/c=0.64% Reso.

  24. dE/dx resolution dE/dxreso.: 5.80% p K 

  25. TOF calibration TOF Barrel:103ps Design：100ps Endcap TOF：125ps Design：110ps

  26. EMC calibration Barrel energy resolution • energy deposit for e+e-gg energy resolution for Bhabha events Position resolution for Bhabha 4.4 mm

  27. MUON Chamber Efficiency Spatial resolution Single counting rate

  28. Data Taking in 2009 • March – April: y’ • ~ 100 M events = 4*CLEOc = 7*BESII • April- June: J/y • ~ 500 M events = 8*BESII • June： a few days at 3.0 & 3.65GeV • After summer: • Possibly y” scan if beam energy is stable and/or beam energy monitor is in place

  29. Integral luminosity accumulated Corresponding to ~100M y’ events

  30. Peak luminosity in 2009

  31. Physics at y’ • Spin-singlets • hc (resonance parameters, production & decays) • c (resonance parameters, …) • c’ (resonance parameters, production & decays) • ’ hadronic decays • VP: , K*K, … (Dalitz analysis) • PP: +-, K+K-, KSKL (benefit from good momentum resolution and part ID) • cc decays • New states

  32. y’ energy scan Beam energy spread: 1.4 MeV

  33. Some physics signals L signal 0 signal K* signal (2S) cJ

  34. ’ l+l- : signals of cJ, 0 and   c1c2 0 BESIII Software/Physics Workshop

  35. Inclusive  Spectrum c1 c2 co c1,2 J/ c

  36. physics at J/y • confirm the X(1860) in J/pp • confirm the X(1835) in J/’+-. • check J/ ’00 ? • confirm X(1810) in J/ • confirm X(1580), X(2075), Y(2175) … • study inclusive photon spectrum • study J/, ’, ’’ and 00 • provide c sample (Br(J/   c)  1.3%) • more J/ and c decay modes

  37. Confirm X(1835) at BESIII BESII data  58M J/ BESIII MC  58M J/  5.1 > 10  > 10   6

  38. Confirm ppbar threshold enhancement at BESIII ( 58M J/ ) 2 years data taking at BESII 2 weeks data taking at BESIII

  39. Y(2175) in J/f0(980) at BESIII BESII data  58M J/ BESIII MC  58M J/ = 1.5% =12 MeV 5.5  = 7.9% =4 MeV > 10

  40. A lineshape scanof y(3770) 45 d, ~ 90 pb-1 “fast energy calibration 30 energy points 9 energy points 30 energy points pb-1 (may be a little bite more) L PRL101 (2008) 102004 BES-II

  41. Summary • physics program at tau-charm is very rich • The BESIII detector is successfully constructed • Computing facility and offline software are ready for large scale data production and physics analysis • A total of 13 M psi’ events are collected in 2008. Detector calibration are performed, showing that • All detector components work well and stable • Detector resolution met design specifications • A total of 100 M psi’ events are collected this year, and great physics results are expected to come soon

More Related