BEPCII/BESIII. Frederick A. Harris University of Hawaii. For the BES Collaboration

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1 BEPCII/BESIII e + e - Collisions from phi to psi Budker Institute of Nuclear Physics Novosibirsk, Russia Feb. 27- Mar. 2, 2006 Frederick A. Harris University of Hawaii 1 For the BES Collaboration

2 The Beijing Electron Positron Collider (BEPC) L ~ /cm 2 s at J/ψ peak E cm ~ 2-5 GeV A unique e + e - machine in the τ-charm energy region until CLEOc.

3 BEPCII: a high luminosity double ring collider SC RF Beams 3

4 BEPCII Design goal Energy range GeV Optimum energy 1.89 GeV Luminosity 1 x cm -2 s 1.89 GeV Injection Synchrotron mode Full energy injection: GeV Positron injection speed > 50 ma/min GeV 4

5 Design Goals and Main Parameters Parameters Unit BEPCII BEPC Operation energy (E) GeV Injection energy (E inj ) GeV Circumference (C) m β * -function at IP (β * x / β * y ) cm 100/ /5 Tunes (ν x /ν y /ν s ) 6.57/7.61/ /6.7/0.02 Hor. natural emittance (ε x0 ) mm mr GeV GeV Damping time (τ x /τ y /τ e ) GeV 28/28/14@1.89 GeV RF frequency (f rf ) MHz RF voltage per ring (V rf ) MV Number of bunches (N b ) Bunch spacing m Beam current Colliding GeV ~2 GeV ma SR 2.5GeV 130 Bunch length (cm) σ l cm ~1.5 ~5 Impedance Z/n 0 Ω ~ 0.2 ~4 Crossing angle mrad ±11 0 Vert. beam-beam param. ξ y Beam lifetime hrs luminosity@1.89 GeV cm -2 s

6 e + -e - Colliders: Past, Present and Future L (cm -2 s -1 ) L (cm -2 sec -1 ) SUPER FACTORIES KEK B and PEP II DAFNE2 DAFNE BEPCII CESRc VEPP2000 DORIS BEPC VEPP2M SPEAR ADONE KEK B PEP II CESR VEPP4M TRISTAN PETRA LEP GLC FACTORIES COLLIDERS E cm (GeV) E (GeV) 6

7 Magnet System Bending magnets Quadrupole magnets Sextupole magnets Dipole correctors 7

Storage ring: Major magnets, superconducting RF cavities and quadrupole

8 BEPCII Status BEPCII linac installation complete; most design specifications reached. Storage ring: Major magnets, superconducting RF cavities and quadrupole magnets, as well as the cryogenics system have been completed, and their installation is under way. Beam collisions expected in spring

9 BESIII Detector Muon Counter SC magnet TOF Be beam pipe Drift Chamber CsI(Tl) calorimeter 9

10 MDC Parameters R inner: 63mm ; R outer: 810mm Length (out.): 2582 mm Inner cylinder: 1.2 mm Carbon fiber Outer cylinder: 11.5 mm CF with 8 windows Sense wire : 25 micron gold-plated tungsten (plus 3%Rhenium ) Layers (Sense wire ): 43 Field wire: 110 micron gold-plated Aluminum Gas: He + C3H8 (60/40) σ x ~ 130 μ m Cell: inner chamber mm σ P outer chamber mm ~ 0.5 P σ de dx ~ 6 % de Expected performance 10 dx

11 MDC 11

12 Wire Stringing Complete 12

13 Beam test at KEK Prototype tested in a 1T magnetic field at KEK 12GeV PS last year. Results: spatial resolution better than 130 µm cell efficiency over 98% de/dx resolution better than 5% (3σ π/k separation exceeding 700MeV/c). 13

CsI(Tl) crystal calorimeter Design goals: Energy: 2.5% @ 1GeV Spatial: 0.

14 CsI(Tl) crystal calorimeter Design goals: Energy: 1GeV Spatial: 1GeV Crystals: Barrel: 5280 w: kg Endcaps: 960 w: 4051 kg Total: 6340 w: 25.6 T 14

15 Many useful suggestions from Alexander Bondar. 15

16 Testing: Size Source tests ( 137 Cs) LED tests PD tests Preamp tests Cosmic ray tests Beam tests (6 x 6 array): CsI Calorimeter X position ADC 16

17 Mechanical structure A 1/60 prototype Status: Assembly starts soon. Should be completed by end of year. By the end of the year, all electronics boards should be tested and installed. 17

18 Crucial for particle ID Barrel 50mm x 60mm x 2320 mm (inner layer). BC408 2 layers Endcap 48 fan shaped pieces each end. BC404 PMT: Hamamatsu R5942 TOF 18

19 TOF Performance Time resolution 1-layer (intrinsic): Belle: 70 to 80 ps Beam tests: < 90 ps Simulation: < 90 ps Time resolution of two layers is 100ps to 110ps for kaon and pions. Capability of K/π separation K/π separation: 2 σ separation up to 0.9 GeV/c. 19

20 Beam tests of TOF module TOF module includes: scintillator, PMTs, preamps, 18m cable, VME readout board of FEE. Pion: 104±11ps proton: 70±2ps Electron: 94±3ps Time resolution from beam test of prototype(including scintillator, PMT, preamp, electronics, cable). Time difference of two TOF layers: no errors from reference time (T o ) or position. 20

21 TOF Monitor System Monitor the amplitude and time performance of each channel including PMTs and electronics. Being designed by University of Hawaii. Just approved by DOE: 3/1/2006 Laser connector fiber Light splitter TDC start ADC gate Fiber Electronic switch PMT Wrapped with steel tube Fiber bundles TOF endcap 48 fibers TOF endcap 48 fibers TOF barrel 176 fibers TOF barrel 176 fibers fiber PMT TOF barrel PMT 21

Superconducting Magnet Coil: single layer solenoid Cooling mode: two phase helium force flow Superconductor: Al stabilized NbTi/Cu Winding: inner winding Cold mass support: tension rod Thermal

22 Superconducting Magnet Coil: single layer solenoid Cooling mode: two phase helium force flow Superconductor: Al stabilized NbTi/Cu Winding: inner winding Cold mass support: tension rod Thermal shield: LN 2 shield, MLI Flux return: barrel/end yoke, pole tip Cryostat Inner radius 1.375m Outer radius 1.7m Length 3.91m Coil Mean radius 1.482m Length 3.52m Cable dimension 3.7mm*20mm Electrical parameters Central field 1.0T Nominal current Inductance Stored energy Cold mass Total Weight 3650A 2H 10MJ 3.6ton 15ton Radiation thickness 2X 22 0

23 BESIII Magnet Progress wiring Thermal insulation assembly transportation installation 23

24 Field mapping Computer controlled 3D mapping machine is under development. Field measuring accuracy < 0.25%. Measure ~90000 points with 0.5 mm position accuracy. Mapping device Status: Complete cooling test of the magnet before summer. Complete the field mapping together with SCQ before Dec. 31,

25 Muon Chamber Barrel + EndCap; RPC as μ detector; Barrel : 9 layers EndCap: 8 layers One dimension read-out strips; 25

26 RPCs Electrodes made from a special type of phenolic paper laminate on bakelite. Have good surface quality(~200nm). Extensive testing and long term reliability testing done. Have high efficiency, low counting rate and dark current, and good long-term stability. 26

27 (RPC module) Total of 64 endcap modules, 72 barrel modules; Gas: Ar:C2H2F4:Iso_Butane = 50:42:8 HV voltage: 8000V; One module contains two RPC layers and one readout layer. 27

28 28 All RPC production, assembly, testing, and installation completed.

29 Test Result after installation - endcap Average strip efficiency: 0.97 Spatial resolution: 16.6mm Mean of 64 endcap RPC =

30 μ/π Identification Efficiency From Simulation Using Muc Info only % μ efficiency Design Goal π fake rate GeV/c Ratio of π decay to μ before entering Muc 30

31 Trigger and DAQ The trigger design is almost finalized; uses FPGA. By the end of the year, all the boards should be tested and installed. The whole DAQ system tested to 8K Hz for the event size of 12Kb, a factor of two safety margin. The whole DAQ system tested during beam test with MDC and EMC L1 trigger rate: 4 KHz Event Size: 12 KBytes Bandwidth after L1: 48 MByte/sec Dead time: < 5% 1000 * BESII DAQ system 31

32 Offline software BOSS BES Offline Software System based on Gaudi. BES III Software Generator HepEvt Event Converters G4Event Simulation McTruth Framework Core Software Calibration & Database BES III RawData RawData CnvSvc Calibration Algorithms Digits RecHits Digitization Reconstruction Algorithms Hits RecTracks Reconstruction Simulaton Histograms Ntuples Analysis Tools DstTracks Rec2DstAlg DstData RootDstCnvSvc Physics Analysis Software Tremendous amount accomplished so far. Much more to do. 32

33 Event Display Tool: BesVis Based on ROOT, OpenGL, X3D and XML Support both 2D and 3D view Operations and controls available through menu and toolbar items First version was released in December /01/

4 MeV Sub-detector Design MC MDC σ w (μm) 130 110 σ p /p 0.5% 0.

34 SIMULATION Based on Geant4 MDC tracking performance: μ - at pt = 1GeV/c Momentum resolution σ = 0.4 MeV Sub-detector Design MC MDC σ w (μm) σ p /p 0.5% 0.4% σ de/dx 6-7% 6% TOF σ t (ps) EMC σ E /E 2.5% 2.2% σ xy (mm) MUC ε(μ ID ) 95% 96% ε(π->μ) 6% 6.2% EMC (barrel) Energy Resolution -single γ 34

Muon Counter TOF Window Ext track Fired strips β 1.2 1.

35 Muon Counter TOF Window Ext track Fired strips β p(gev/c)

36 Physics Simulations 50, 000 ψ Inclusive event sample. ~3MeV K S π + π Λ pπ ~1.2MeV

37 50, 000 ψ Inclusive event sample. A RooPlot of "D0 to Kpi" Events / ( ) D 0 K D0 to Kpi A RooPlot of "D0 to Kpipi0" π σ(m BC ) ~ 1.2 MeV/c 2 σ(δe) = 7 MeV + + π A RooPlot of "D0 to K3pi" Events / ( ) D 0 K π D0 to K3pi A RooPlot of "D0 to K0bpipi" + π + π Events / ( ) D 0 K π + π 0 Events / ( ) D 0 K S π + π D0 to Kpipi D0 to K0bpipi 37

38 Ψ' γχ cj, χ cj γj/ ψ BESIII: (8M, M.C.) m(χ c1 ) = 3.508GeV, m(χ c2 ) = 3.553GeV; σ(χ c1 ) = 8.1MeV, σ(χ c2 ) = 9.4MeV. χ c1 χ c2 Ψ' J/ψ(π 0, η), (π 0, η) γγ m(η) = 549 MeV m(π 0 )=135 MeV η χ c0 π 0 m(χ c- ) =3.413GeV, σ(χ c0 ) =9.0MeV. 38

39 Ψ' γχ cj, χ cj multi-tracks Ψ' γχ cj, χ cj ππππ χ c0 χ c1 χ c2 BESIII: (0.5 M, M.C.) Ψ' γχ cj, χ cj ππkk χ c0 χ c1 χ c2 η c Events Ψ' γχ cj, χ cj (6π) χ c1 χ c2 Inv.mass of chrg.trks. (GeV) χ c0 Ψ' tail 39

40 Physics Topics at BESIII Charmonium: J/ψ, ψ(2s), η C (1S) in J/ψ decay, χ C{0,1,2}, η C (2S) and h C ( 1 P 1 ) in ψ(2s) decay, ψ(1d) and so on Exotics : hybrids, glueballs and other exotics in J/ψ and ψ(2s) radiative decays; Baryons and excited baryons in J/ψ and ψ(2s) hadronic decays; Mesons and mixing of quark and gluon in J/ψ and ψ(2s) decays; Open charm factory : Absolute BR measurements of D and Ds decays, Rare D decay, D 0 -D 0 bar mixing, CP violation, f D+, f Ds, form factors in semi-leptonic D decays, precise measurement of CKM (Vcd, Vcs) CP violation and strong phase in D Dalitz Decays, light spectroscopy in D 0 and D + Dalitz Decays. Electromagnetic form factors and QCD cross section; New Charmonium states above open charm threshold---r values...; tau physics near the threshold. 40

41 Production Average Lum: L = 0.5 Peak Lum.; One year data taking time: T = 10 7 s N event /year = σ exp L T Resonance Mass(GeV) CMS Peak Lum. (10 33 cm -2 s -1 ) Physics Cross Section (nb) Nevents/yr J/ψ τ ψ(2s) D 0 D 0 bar D + D DsDs DsDs Huge J/ψ and ψ(2s) samples at BESIII 41

42 BESIII and CLEOc comparison Detector MDC BES III σ XY (μm) = 130 ΔP/P ( 0 / 0 ) = 0.5 %(1 GeV) CLEOc 90 μm 0.5 % EMC TOF μ counter magnet σ de/dx ( 0 / 0 ) = 6-7 % Δ E/ E( 0 / 0 ) = 2.5 %(1 GeV) σ z (cm) = 0.5cm/ E σ T (ps) = /layer Double layer 9 layers 1.0 T 6% 2.0% 0.3 cm / E Rich T

43 Future In US: CLEOc stops in 2008 BaBar stops running in Fermilab stops collider physics in In China: BESIII commissioning in summer BESIII will be a unique facility. 43

44 BESIII Collaboration First formal meeting held Jan , 2006 at IHEP, Beijing. Adopted Governance Rules, elected IB Chair and Spokespersons. Institute of High Energy Physics University of Science and Technology Peking University Tsinghua University Shangdong University Nankai University Central China Normal University University of Anhui University of Zhejiang University of Zhengzhou Nanjing Normal University Nanjing University Shanxi University Sichuan University Henan Normal University University of Hawaii University of Washington University of Tokyo Joint Institute of Nuclear Research, Dubna GSI University of Bochum University of Giessen Need more here! 44

Physics preparation Write a yellow book on BESIII physics: a summary of theoretical and experimental tau-charm physics and the BESIII physics reach.

45 Physics preparation Write a yellow book on BESIII physics: a summary of theoretical and experimental tau-charm physics and the BESIII physics reach. Charm2006: Workshop on Tau-Charm Physics June 5 7, 2006, Beijing, China phy_book/book/book.html Workshops: Charm 2006: International tau-charm workshop Beijing June US-China workshop on HEP cooperation 45

46 Summary BEPCII linac installation complete. Elements for collider complete; installation beginning. BESIII hardware and software progressing rapidly, although still much to do. Commissioning expected in summer Rich physics after CLEO-c. Collaborators welcomed! 46

47 БОЛЬШОЕ СПАСЙБО T = 20 C (-) 47

48 БОЛЬШОЕ СПАСЙБО T = 20 C 48

BEPCII/BESIII. Frederick A. Harris University of Hawaii For the BES Collaboration. DPF 2006 Oct. 30 Nov. 3, 2006 Honolulu, HI 1/29/2008 DPF2006 1

BEPCII/BESIII. Frederick A. Harris University of Hawaii For the BES Collaboration. DPF 2006 Oct. 30 Nov. 3, 2006 Honolulu, HI 1/29/2008 DPF2006 1 BEPCII/BESIII DPF 2006 Oct. 30 Nov. 3, 2006 Honolulu, HI Frederick A. Harris University of Hawaii For the BES Collaboration 1/29/2008 DPF2006 1 The Beijing Electron Positron Collider (BEPC) L ~ 5 10 30