1/29/2008 DPF2006 1

Frederick A. HarrisFrederick A. HarrisUniversity of HawaiiUniversity of Hawaii

For the BES CollaborationFor the BES Collaboration

BEPCII/BESIIIDPF 2006Oct. 30 – Nov. 3, 2006Honolulu, HI

The Beijing Electron Positron Collider (BEPC)

L ~ 5 ×1030 /cm2⋅s at J/ψ peak Ecm~ 2 - 5 GeV

A unique e+e- machine in the τ-charm energy region until CLEOc.

1/29/2008 DPF2006 3

BEPCII: a high luminosity double–ring collider

SC RF

Beams

1/29/2008 DPF2006 4

BEPCII Design goal

Energy range 1 – 2.1 GeV

Optimum energy 1.89 GeV

Luminosity 1 x 10 33 cm-2s-1 @ 1.89 GeV

Injection Full energy injection: 1.55 − 1.89 GeV Positron injection rate > 50 mA/min

Synchrotron mode 250 mA @ 2.5 GeV

Use many bunches and mini-beta.

1/29/2008 DPF2006 5

Design Goals and Main ParametersParameters Unit BEPCII BEPC

Operation energy (E) GeV 1.0−2.1 1.0−2.5 Injection energy (Einj) GeV 1.55−1.89 1.3

Circumference (C) m 237.5 240.4 β*-function at IP (βx

*/ βy*) cm 100/1.5 120/5

Tunes (νx/νy/νs) 6.57/7.61/0.034 5.8/6.7/0.02 Hor. natural emittance (εx0) mm⋅mr 0.14 @1.89 GeV 0.39 @1.89 GeV Damping time (τx/τy/τe) 25/25/12.5 @1.89 GeV 28/28/14@1.89 GeV

RF frequency (frf) MHz 499.8 199.533 RF voltage per ring (Vrf) MV 1.5 0.6−1.6

Number of bunches (Nb) 93 2×1 Bunch spacing m 2.4 240.4

Colliding 910 @1.89 GeV ~2×35 @1.89 GeV Beam current SR

mA 250 @ 2.5GeV 130

Bunch length (cm) σl cm ~1.5 ~5 Impedance |Z/n|0 Ω ~ 0.2 ~4 Crossing angle mrad ±11 0

Vert. beam-beam param. ξy 0.04 0.04 Beam lifetime hrs. 2.7 6−8

luminosity@1.89 GeV 1031cm-2s-1 100 1

1/29/2008 DPF2006 6

BEPCII Status• BEPCII linac installation completed in 2005; most design specifications reached.

• Storage ring: Major magnets, superconducting RF cavities and quadrupolemagnets, as well as the cryogenics system have been completed, and theirinstallation is nearly complete.

• SR runs before the end of this year.

• Beam collisions expected in summer/fall 2007.

1/29/2008 DPF2006 7

BESIII Detector

Be beam pipe

SC magnetMuon Counter

Drift Chamber

CsI(Tl) calorimeter

TOF

1/29/2008 DPF2006 8

MDCParametersR inner: 63mm ; R outer: 810mm Length (out.): 2582 mm Inner cylinder: 1.2 mm Carbon fiberOuter cylinder: 11.5 mm CF with 8 windowsSense wire : 25 micron gold-plated tungsten (plus 3%Rhenium ) --

- 6796 Layers (Sense wire ): 43

Expected performance

Field wire: 110 micron gold-plated Aluminum --- 21884Gas: He + C3H8 (60/40)Cell: inner chamber --- 6 mm

outer chamber --- 8.1 mmPolar angle: |cos θ| < 0.83 (all layers)

< 0.93 (20 layers)%6~

@1GeV/C%5.0~

130~

dxdE

P

m

dxdE

P

x

σ

σμσ

1/29/2008 DPF2006 9

MDC

1/29/2008 DPF2006 10

MDC Status: Wire Stringing CompletePreamp installation in progress.

Cosmic ray running in about one month.

1/29/2008 DPF2006 11

Beam test at KEKPrototype tested in a 1T magnetic field

at KEK 12GeV PS. Results:• spatial resolution better than 130 µm• cell efficiency over 98%• dE/dX resolution better than 5%

(3σ π/K separation exceeding 700MeV/c).

1/29/2008 DPF2006 12

CsI(Tl) crystal calorimeter• Design goals:

– Energy: 2.5% @ 1GeV– Spatial: 0.6cm @ 1GeV

• Crystals:– Barrel: 5280 w: 21564 kg– Endcaps: 960 w: 4051 kg– Total: 6340 w: 25.6 T– 5 x 5 cm2 front face; 6.5 x

6.5 cm2 back– 28 cm length (15 radiation

lengths)• Have all barrel and most endcap

crystals

1/29/2008 DPF2006 13

Readout: Two Hamamatsu S2744-08 10 mm x 20 mm photodiodes

1/29/2008 DPF2006 14

Testing:•Size•Source tests (137 Cs)•LED tests•PD tests•Preamp tests•Cosmic ray tests•Beam tests (6 x 6 array):

X position

ADC

CsI Calorimeter

1/29/2008 DPF2006 15

Mechanical structure

A 1/60 prototype

Mechanical structure now at IHEP

Status:• Assembly starts

soon. Barrel completed by April 07.

1/29/2008 DPF2006 16

TOFCrucial for particle ID• Barrel

– 50mm x 60mm x 2320 mm (inner layer).

– BC408 – 2 layers – 88 in each

• Endcap– 48 fan shaped pieces –

each end.– BC404

• PMT: Hamamatsu R5942– Fine mesh

1/29/2008 DPF2006 17

TOF Performance

Time resolution 1-layer (intrinsic):

Belle: 70 to 80 psBeam tests: < 90 psSimulation: < 90 ps

Time resolution of two layers is 100ps to 110psfor kaon and pions.

K/π separation: 2 σseparation up to 0.9 GeV/c.

Capability of K/π separation

1/29/2008 DPF2006 18

TOF Monitoring System

TOF endcap 48 fibersTOF endcap 48 fibersLaser Light splitter

TOF barrelPMT PMT

Ref. PMTTDC startADC gate

Fiber

TOF barrel 176 fibersTOF barrel 176 fibers

Electronic switch

fiber

Fiber bundles

connector

Monitor the amplitude and time performance of each channel including PMTs and electronics. Being built by University of Hawaii:

Use mirror to steer beam – like BESII.Purchase fiber cable bundles (2 cables).

2008-1-29 DPF2006 19

Fiber Bundle Cables (need 2)Barrel TOF

EC TOF

1/29/2008 DPF2006 20

Test Setup at UH• Need TOF counter and readout

for testing TOF laser calibration system.

• Use Belle BC408 TOF counter and 2 BES fine mesh phototubes.

• Test with cosmic ray telescope.• Caen VME TDC and QDC with

computer to readout.• Next install fibers and pulse with

N2/dye laser.

1/29/2008 DPF2006 21

Coil: single layer solenoid Cooling mode: two phase helium force

flowSuperconductor: Al stabilized NbTi/CuWinding: inner windingCold mass support: tension rodThermal shield: LN2 shield, MLIFlux return: barrel/end yoke, pole tip

Superconducting MagnetCryostat

Inner radius 1.375m

Cable dimension 3.7mm*20mmElectrical parameters

Central field 1.0TNominal current 3650A

Stored energy 10MJCold mass 3.6tonTotal Weight 15ton

Inductance 2H

Radiation thickness 2X0

Outer radius 1.7mLength 3.91m

CoilMean radius 1.482mLength 3.52m

First of its kind built in China.

1/29/2008 DPF2006 22

BESIII Magnet ProgressThermal insulation assembly

transportation

wiring

installation

1/29/2008 DPF2006 23

0 500 1000-0.018

-0.016

-0.014

-0.012

-0.010

-0.008

-0.006

-0.004

-0.002

0.000

0.002

0.004

0.006

VTL1A-VTL2A VTLL1A-VTLL2A VTLL1B-VTLL2B VTLL3A-VTLL4A VTLL3B-VTLL4B VTM6A-VTM1A VTM6A-VTM5A VTM1A-VTM2A VTM3A-VTM4A VTM4A-VTM5A

Vol

tage

(V) Time:22:00Time:19:00

Voltage curve shows that the magnet is in super-conducting state.

Magnetic field 10029.8 Gauss.

BESIII Magnet ProgressSept. 19, 2006

1/29/2008 DPF2006 24

Muon Chamber

Barrel + EndCap;

RPC as μ detector;Barrel : 9 layersEndCap: 8 layersOne dimension read-out strips;

1/29/2008 DPF2006 25

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 .

1/29/2008 DPF2006 26

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

1/29/2008 DPF2006 27Spring 2005: All RPC production, assembly, testing, and installation completed.

1/29/2008 DPF2006 28

Test Result after installation - endcapAverage strip efficiency: 0.97 Spatial resolution: 16.6mm

Mean of 64 endcapRPC = 0.95

1/29/2008 DPF2006 29

μ/π Identification Efficiency

0

10

20

30

40

50

60

70

80

90

100

0. 5 0. 75 1

Using Muc Info only

%

GeV/c

90.3

6.24

5.59.0

12.618.9

12.0

91.287.6

π fake rate

μ efficiency

Ratio of π decay to μbefore entering Muc

Design Goal

15.09.0 6.0

From Simulation

1/29/2008 DPF2006 30Fall 2006

1/29/2008 DPF2006 31

Trigger and DAQ• The trigger design is almost finalized; pipelined and uses FPGAs. • By end of the year, all the boards should be tested.• Whole DAQ system tested to 8K Hz for the event size of

12Kb, a factor of two safety margin. • Whole DAQ system tested during beam test with MDC and EMC.

L1 trigger rate: 4 KHzEvent Size: 12 KBytes

Expected bandwidth after L1: 48 MByte/sec

Dead time: < 5%

1000 * BESII DAQ system

1/29/2008 DPF2006 32

Offline software

HepEvt McTruthG4Event

HitsDigitsRawDataCnvSvcBES I I I RawData

Generator EventConverters Simulation

Digitization

ReconstructionAlgorithms

CalibrationAlgorithms RecHits RecTracks

AnalysisTools DstTracksHistograms

Ntuples

RootDstCnvSvcDstData

Rec2DstAlgReconstruction

Calibration &Database

Framework CoreSoftware

Simulaton

Physics AnalysisSoftware

BES III Software

BOSS – BES Offline Software Systembased on Gaudi.

Tremendous amount accomplished so far.Much more to do.

1/29/200812/01/2006 DPF2006W.Li and Y. Mao 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 2005.

1/29/2008 DPF2006 34

SIMULATION – Based on Geant4

MDC tracking performance:

Sub-detector Design MCMDC σw (μm) 130 110

σp/p 0.5% 0.4%σdE/dx 6-7% 6%

TOF σt (ps) 90 85EMC σE/E 2.5% 2.2%

σxy(mm) 6 4.8MUC ε(μID) 95% 96%

ε(π->μ) 6% 6.2%

μ- at pt = 1GeV/cMomentum resolutionσ = 0.4 MeV

EMC (barrel) Energy Resolution -single γ

1/29/2008 DPF2006 35

Muon Counter

Ext track

Fired strips

Window

p(GeV/c)0 0.2 0.4 0.6 0.8 1 1.2

β

0.20.30.40.50.60.70.80.9

11.11.2

TOF

~1.2MeV

pπ→Λ

~3MeV−+→ ππKS

Physics Simulations

50, 000 ψ˝ Inclusiveevent sample.

1/29/2008 DPF2006 37

D0 to Kpi1.81 1.82 1.83 1.84 1.85 1.86 1.87 1.88

Eve

nts

/ ( 0

.000

8 )

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

D0 to Kpi1.81 1.82 1.83 1.84 1.85 1.86 1.87 1.88

Eve

nts

/ ( 0

.000

8 )

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

A RooPlot of "D0 to Kpi"

D0 to K3pi1.81 1.82 1.83 1.84 1.85 1.86 1.87 1.88

Eve

nts

/ (

0.00

08 )

0

50

100

150

200

250

300

350

400

450

D0 to K3pi1.81 1.82 1.83 1.84 1.85 1.86 1.87 1.88

Eve

nts

/ (

0.00

08 )

0

50

100

150

200

250

300

350

400

450

A RooPlot of "D0 to K3pi"

D0 to Kpipi01.81 1.82 1.83 1.84 1.85 1.86 1.87 1.88

Eve

nts

/ ( 0

.000

8 )

0

200

400

600

800

1000

1200

1400

1600

D0 to Kpipi01.81 1.82 1.83 1.84 1.85 1.86 1.87 1.88

Eve

nts

/ ( 0

.000

8 )

0

200

400

600

800

1000

1200

1400

1600

A RooPlot of "D0 to Kpipi0"

D0 to K0bpipi1.81 1.82 1.83 1.84 1.85 1.86 1.87 1.88

Eve

nts

/ ( 0

.000

8 )

0

50

100

150

200

250

300

350

400

D0 to K0bpipi1.81 1.82 1.83 1.84 1.85 1.86 1.87 1.88

Eve

nts

/ ( 0

.000

8 )

0

50

100

150

200

250

300

350

400

A RooPlot of "D0 to K0bpipi"

+−→ πKD0−++−→ πππKD0

+π

00 ππKD +−→−+→ ππKD S

0

50, 000 ψ˝ Inclusive event sample.

σ(mBC) ~ 1.2 MeV/c2

σ(ΔE) = 7 MeV

1/29/2008 DPF2006 38

BESIII: (8M , M.C.)m(χc1) = 3.508GeV,m(χc2) = 3.553GeV;σ(χc1) = 8.1MeV,σ(χc2) = 9.4MeV.

Ψ' γχcJ , χcJ γJ/ ψ

χc1 χc2

π0

η

Ψ' J/ψ(π0, η), (π0, η) γγ

χc0m(η) = 549 MeVm(π0) =135 MeV

m(χc-) =3.413GeV,σ(χc0) =9.0MeV.

1/29/2008 DPF2006 39

Physics Topics at BESIIIOpen charm factory :

• Absolute BR measurements of D and Ds decays• Rare D decay• D0 - D0bar mixing• CP violation• f D+, fDs form factors in semi-leptonic D decays• precise measurement (1.6% stat.) of CKM (Vcd, Vcs)• CP violation and strong phase in D Dalitz Decays• light meson spectroscopy in D0 and D+ Dalitz Decays.

1/29/2008 DPF2006 40

Physics Topics at BESIII

• Charmonium: J/ψ, ψ(2S), ηC(1S), χC{0,1,2} , ηC(2S), hC(1P1), ψ(1D), etc. • New Charmonium states above open charm threshold• 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.• Electromagnetic form factors and QCD cross section (R values).• tau mass and tau physics near the threshold

Very rich and interesting energy region.

1/29/2008 DPF2006 41

Resonance Mass(GeV)CMS

Peak Lum.(1033cm-2s-1)

Physics Cross Section (nb)

Nevents/yr

J/ψ 3.097 0.6 3400 10 × 109

τ 3.670 1.0 2.4 12 × 106

DsDs 4.030 0.6 0.32 1.0 × 106

ψ(2S) 3.686 1.0 640 3.2 × 109

D0D0bar 3.770 1.0 3.6 18 × 106

D+D- 3.770 1.0 2.8 14 × 106

DsDs 4.140 0.6 0.67 2.0 × 106

Average Lum: L = 0.5×Peak Lum.; One year data taking time: T = 107s

Nevent/year = σexp ×L× T

Production

Huge J/ψ and ψ(2S) samples at BESIII

1/29/2008 DPF2006 42

BESIII CollaborationFirst formal meeting held Jan. 10-12, 2006 at IHEP, Beijing.Adopted Governance Rules, elected IB Chair and Spokespersons. Second collaboration meeting held June 11-13 at IHEP.Management plan adopted.

Institute of High Energy PhysicsUniversity of Science and TechnologyPeking UniversityTsinghua UniversityShangdong UniversityNankai UniversityCentral China Normal UniversityUniversity of AnhuiUniversity of ZhejiangUniversity of ZhengzhouNanjing Normal UniversityNanjing UniversityShanxi UniversitySichuan UniversityHenan Normal University

University of HawaiiUniversity of WashingtonUniversity of TokyoJoint Institute of Nuclear

Research, DubnaGSIUniversity of BochumUniversity of Giessen

Need more here!

1/29/2008 DPF2006 43

FutureIn US:• CLEOc stops in 2008• BaBar stops running in 2008.• Fermilab stops collider physics in 2009.

In China:BESIII commissioning in fall 2007.BESIII will be a unique facility.

☺

1/29/2008 DPF2006 44

Summary• BEPCII linac installation complete.• Installation of collider nearly complete;

synchrotron running fall 2006.• BESIII hardware and software progressing

rapidly, although still much to do.• Commissioning expected in fall 2007.• Rich physics program after CLEO-c.

Complementary to B-factories.• Collaborators welcomed!

1/29/2008 DPF2006 45

1.0 T1.0 T magnet

----9 layersμ counter

RichσT(ps) = 100-110/layer Double layer

TOF

2.0%0.3 cm /√E

Δ E/√E(0/0) = 2.5 %(1 GeV)σz(cm) = 0.5cm/√E

EMC

6%σdE/dx (0/0) = 6 - 7 %

0.5 %ΔP/P (0/0) = 0.5 %(1 GeV) MDC

90 μmσXY (μm) = 130

CLEOcBES IIIDetector

BESIII and CLEOc comparison