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BEPCII/BESIII

BEPCII/BESIII. Frederick A. Harris University of Hawaii QWG Meeting Sept. 20-22, 2003 Fermilab. Representing:. The Beijing Electron Positron Collider. L ~ ~5 10 30 /cm 2 s at J/ peak E cm ~ 2-5 GeV A unique e + e - machine in the  -charm energy region since 1989.

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BEPCII/BESIII

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  1. BEPCII/BESIII Frederick A. Harris University of Hawaii QWG Meeting Sept. 20-22, 2003 Fermilab Representing:

  2. The Beijing Electron Positron Collider L ~ ~51030 /cm2s at J/ peak Ecm~2-5 GeV A unique e+e- machine in the -charm energy region since 1989.

  3. On Feb. 10, 2003, the Chinese government, the state council, approved officially the BEPCII/BESIII upgrade project

  4. BEPC II Storage ring: Large angle, double-ring RF SR RF + - e e IP

  5. BEPCII Design goal

  6. BEPCII main parameters Passed SLAC review in May 2002.

  7. 工 The BESIII Detector

  8. Main drift chamber • Inner diameter: 63mm; Outer diameter: 810mm; length: 2400 mm • Inner cylinder: 1 mm Carbon fiber, outer cylinder: 10 mm CF with 8 windows • End flange: 18 mm thick Al 7075 ( 6 steps) • 7000 Signal wires : 25(3% Rhenium) mm gold-plated tungsten • 22000 Field wires: 110 mm gold-plated Aluminum • Small cell: inner---6*6 mm2, outer--- 8.2 *8.2 mm2, • Gas: He + C3H8 (60/40) • Momentum resolution (@ 1 GeV/c): • dE/dX resolution: 6-7%.

  9. 85μm

  10. EMC: CsI(Tl) crystals • 6300 crystals, (5.2x 5.2 – 6.4 x 6.4) x 28cm3 (15 X0) • PD readout, noise ~1100 ENC • Energy resolution: 2.5%@1GeV • Position resolution: 5mm@1GeV • Tiled angle: theta ~ 1-3o, phi ~ 1.5o • Minimum materials between crystals

  11. no partition wall Mechanical support structure

  12. Super-conducting magnet • Al stabilized NbTi/Cu conductor from Hitachi • 1.0 T, <5% non-uniformity • 921 turns, 3150A @4.5K • R = 1.475 m, L=3.52m, cold mass 3.6t • Thickness: 1.92 X0 • Inner-winding method

  13. 图3.8.20 桶部光电倍增管的支撑环，内外两层共176个孔。 Particle ID: TOF system • 392 pieces BC408, 2.4 m long, 5cm thick • Time resolution 100-110 ps/layer • PMT: Hamamatzu R5942

  14. m system : RPC • 9 layers, 2000 m2 • Bakelite, no linseed oil • 4cm strips, 10000 channels • Tens of prototypes (up to 1*0.6 m2 ) • Noise less than 0.2 Hz/cm2

  15. Other systems • Electronics design have been almost finished, several prototypes have been successfully tested • Trigger system largely based on FPGA technology have been designed, prototypes underway • DAQ system based on VME/PowerPC and PC farm have been designed, mini-version setup, software underway • Offline computing environment based on a large scale PC farm is under study • MC based on GEANT4, first reconstruction framework released, sub-detector reconstruction code underway

  16. Schedule • 5/2004: BESII detector shutdown • 11/2004: supporting structure/york installation • 3/2005: muon chamber installation • 5/2005: magnet installation • 10/2005: magnetic field mapping • 2/2006: EMC installation • 3/2006: MDC/TOF installation • 6/2006: Cosmic-ray run • 9/2006: BESIII detector in place • 12/2006: tuning of detector/machine

  17. Physics at BEPCII/BESIII • Rich source of resonances, charmonium, and charmed mesons • Transition between perturbative and non-perturbative QCD • Charmonium radiative decays are the best lab to search for glueballs, hybrids, and exotic states

  18. Physics to be studied in -charm region • Search for glueballs, quark-gluon hybrids and exotic states • Charmonium Spectroscopy and decay properties • Precision measurement of R • Tau physics: tau mass, tau-neutrino mass, decay properties, Lorenz structure of charged current, CP violation in tau decays … • Charm physics: including decay properties of D and Ds, fD and fDs;; charmed baryons.

  19. Light quark spectroscopy, mc • Testing QCD, QCD technologies, CKM parameters • New Physics: rare decays, oscillations, CP violations in c- hadrons • ….. • To answer these physics questions, need precision measurements with • High statistics data samples • Small systematic errors

  20. Event statistics at BESIII *CLEO took 10 nb D production cross section while we took 5 nb

  21. Semi-leptonic decays – one year running DVcs /Vcs = 1.6%, DVcd /Vcd = 1.8% Emissing-Pmissing

  22. Pure Leptonic decays One year of running

  23. Absolute Br measurement: clear D tagging beam energy spread important One year of running

  24. Non-leptonic decays One year of running

  25. Comparison with other facilities *CLEO took 10 nb D production cross section while we took 5 nb One year of running

  26. DDbar Mixing at BESIII DDbar mixing in SM ~ 10 –3 -10 –10 DDbar mixing sensitive to “new physics” Our sensitivity : ~ 10-4 D0 D0g(K-p+) (K+p-) Acceptance: ~ 40% Background: ~ 10-4

  27. QCD and hadron production • R-value measurement • pQCD and non-pQCD boundary • Measurement of as at low energies • Hadron production at J/y, y’, and continuum • Multiplicity and other topology of hadron event • BEC, correlations, form factors, resonance, etc.

  28. R-value measurement R-value below 2GeV is important, via radiative return

  29. Errors on R at BESIII

  30. Light hadron spectroscopy • Baryon spectroscopy • Charmonium spectroscopy • Glueball searches • Search for non-qqbar states • Search for 1P1

  31. Tau-charm physics after CLEOc? • CLEOc begins running now! • What important physics issues will remain in 2007? • Is the BESIII detector design adequate to address these? • There will be a workshop on these issues in January 2004 in balmy Beijing. Workshop will be a CLEOc/BES joint effort. • More studies needed before the workshop. • Stay tuned. Will post announcement on the QWG web page. • Please come.

  32. Subdetector BES III CLEOc XY (m) = 130 90 m MDC P/P (0/0) = 0.5 %(1 GeV) 0.5 % dE/dx (0/0) = 6 - 7 % 6% EMC  E/E(0/0) = 2.5 %(1 GeV) z(cm) = 0.5cm/E 2.0% 0.3 cm /E TOF T(ps) = 100-110/layer Double layer Rich m counter 9 layers ---- magnet 1.0 T 1.0 T The detector of BESIII and CLEOc

  33. International collaboration IHEP, Beijing Beijing University , Beijing Tsinghua University , Beijing USTC, Hefei National Central University, Taipei KEK, Tokyo University, Tokyo Hawaii University, Honolulu Washington University, Seattle More collaborators welcomed

  34. Summary • The BEPCII/BESIII has been approved officially by the chinese government • The initial BESIII detector design is finished, prototyping is underway, mass production is about to start. • Rich physics after CLEO-c (upgrade of BEPCII to 3*1033 cm-2s-1 is possible) • Collaborators are welcomed!

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