UHM Physics and Astronomy - Charm in China: BEPCII/BESIIIfah/bestalks/SLAC... · 2010. 11. 26. ·...

88
11/26/2010 1 Frederick A. Harris Frederick A. Harris University of Hawaii University of Hawaii Charm in China: BEPCII/BESIII SLAC Experimental Seminar June 30, 2009

Transcript of UHM Physics and Astronomy - Charm in China: BEPCII/BESIIIfah/bestalks/SLAC... · 2010. 11. 26. ·...

Page 1: UHM Physics and Astronomy - Charm in China: BEPCII/BESIIIfah/bestalks/SLAC... · 2010. 11. 26. · Charm in China: BEPCII/BESIII SLAC Experimental Seminar June 30, 2009. 11/26/2010

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Frederick A. HarrisFrederick A. HarrisUniversity of HawaiiUniversity of Hawaii

Charm in China: BEPCII/BESIIISLAC Experimental Seminar

June 30, 2009

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OUTLINEOUTLINE

• Introduction: physicsof tau charm region

• BEPCII• BESIII• ψ(2S) (not even)

preliminary results•Beam energy

measurement• BESIII physics• Summary

IHEP

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CM Energy ranges from 2 to 5 GeV

Luminosity at J/ψ ~ 5 x 1030 cm–2 s -1

Beijing, China

BESII

The Beijing Electron Positron Collider (BEPC)

BESII detector removed in 2004.

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• Light hadron spectroscopy.• 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 (X, Y, Z).• 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 quarks and gluons in J/ψ and ψ(2S) decays.• Electromagnetic form factors and QCD cross section (R values).• tau and charm physics near the threshold. High precision measurements.

Physics of tau – charm regionTremendous

variety:

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Open charm factory :• Absolute BR measurements of D and Ds decays• Rare D decay• D0 - D0bar mixing• Quantum correlations (ψ“)• CP violation, strong phase.• f D+, fDs, form factors in leptonic D decays• Can provide calibrations and tests of lattice QCD.• precise measurement (~1.6%) of CKM (Vcd, Vcs)• light meson spectroscopy in D0 and D+ Dalitz plot analyses.

• Search for new physics.

Very rich and interesting energy region.

Physics of tau – charm region

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BES Highlights:BESI tau mass measurement:

10X better precision

225.018.017.021.0 MeV/c96.1776 ++

−−=τm

J. Z. Bai et al, PRD53, 20 (1996).

92 citations

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BESI -- Tau mass measurementLifetime, leptonic branching ratio, and mass are related in Standard Model:

Status 1992 (2.4 σ)

and 1994 (1.3 σ)

Status 2006

A. Pich, Charm06 talk

1992

1994

),(192)(

)()( 3

52

ecorF

e

ee mmF

mGeeB

e ττ

τ

ττ πυυττ

υυτυυτ =

→→

=→Γ

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BESII: R

Before BES R Scan After BES R Scan

BES reduces R errors from 15 – 20 % to an averageof 6% in the 2 – 5 GeV region. Important region!

PRL 84, 594 (2000).PRL 88, 101802 (2002).83 + 186 citations

R = σ(e+e- → hadrons)/σ(e+e- → μ+μ-)

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R measurementR measurementNeeded to improve precision of α(M2

Z):Uncertainties in α introduced when it is extrapolated to

the Z-pole:

Dominant uncertainty due to hadronic vacuum polarization.This is determined from R values using a dispersion

relation.

The Higgs mass determined from radiative corrections in the SM is very sensitive to α(M2

Z).

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SM Fit to mH

GeVmGeVm

H

H

17062 53

30

<= +

(95% C.L.) GeVmGeVm

H

H

21298 58

38

<= +

Burkhardt and Pietrzyk, Phys. Lett. B513, 46 (2001).]

(95% C.L.)

Without BES dataWith BES data

Data from tau-charm mass region

important for standard model fits.

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Latest R result:

BES, PLB 677, 239 (2009).

error ~ 4%

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Threshold enhancement in J/ψ → γp p

BESII: enhancement seen near threshold in Mpp in J/ψ → γ p p.

If fitted with an S-wave resonance:

M(pp) - 2mp (GeV)

3-body phase space

M = 1859 MeV/c2

Γ < 30 MeV/c2 (90% CL)

+3 +5−10 −25

fitted peak location

acceptance

J/ψ γpp

0 0.1 0.2 0.3

Phys. Rev. Lett. 91, 022001 (2003) 156 citations

“The BES Particle”

Klempt: Glueballs, Hybrids,

and Pentaquarks

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pp bound state (baryonium)?

+ n + −

deuteron:

loosely bound 3-q 3-q color singlets with Md = 2mp- ε

baryonium:

loosely bound 3-q 3-q color singlets with Mb = 2mp-δ ?

attractive nuclear force attractive force?

There is lots & lots of literature about this possibility

E. Fermi, C.N. Yang, Phys. Rev. 76, 1739 (1949)…I.S. Sharpiro, Phys. Rept. 35, 129 (1978)C.B. Dover, M. Goldhaber, PRD 15, 1997 (1977)…A. Datta, P.J. O’Donnell, PLB 567, 273 (2003)]M.L. Yan et al., hep-ph/0405087B. Loiseau et al., hep-ph/0411218…

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• A structure at 2175MeV was observed in

e+e- γ ISR φf0(980), e+e- γISR K+K-f0(980)

MeV201658MeV15102175

±±=Γ±±=M

Observation of a new 1-- resonance Y(2175) at BaBar

Phys. Rev. D 74 (2006) 091103(R)

Y(2175)

6.2 σ

Speculation: may be ss-bar version of Y(4260) since 1--

and similar decay. [BaBarPRL95, 142001 (2005).]

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5.5 σ

M(φf0(980)) GeV/c2

Simultaneous fit to signal and sideband events withsingle BW + p3

BESII J/ψ → ηφf0(980) Y(2175)

Mass (GeV/c2) Width (GeV/c2)

BES 2.186±0.010±0.006 0.065±0.023±0.017

BABAR 2.175±0.010±0.015 0.058±0.016±0.020

40

0

10)73.075.023.3())980((

))980()2175(())2175(/(−−+ ×±±=→

•→•→

ππ

ϕηψ

fB

fYBYJB

58 M J/ψFinal states: η γγ, φ K+K-, f0(980) π+π-

BES, PRL 100, 102003 (2008).

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The future of BEPC• Decision to build BEPC in the early 1980s was a great success:

(Pief’s advice was instrumental, and SLAC provided much assistance. )– Rich physics results:

• A total of ~120 papers in PRL, PRD, PLB, etc.• A total of ~300 entries in the Particle Data Book.• Several highlights well known to the community.

– Established foundation of particle physics and its related technology in China.

– Started the era of synchrotron radiation studies in China.– Technology transfer.

• In the 1990s, there was discussion of the future. The conclusion was to continue tau-charm physics with a major upgrade of the accelerator and detector (BEPCII/BESIII).

• The physics window is precision charm physics and the search for new physics.– High statistics: high luminosity machine + high quality detector.– Small systematic error: high quality detector.

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History1979 First US/PRC HEP meeting1984 BEPC approved1988 first electron positron

collisions1991 US/China BESI

Collaboration formed1992 tau mass measurement

published1995/96 BESII Upgrade1998/99 R Scan (91 energy points)2000/01 J/psi data (58 M)2002 psi’ data (14M)2003 BEPCII/BESIII approved2006 BESIII collaboration

formed2008 First event in BESIII

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BESIII CollaborationInstitute of High Energy PhysicsUniversity of Science and TechnologyPeking UniversityTsinghua UniversityShangdong UniversityNankai UniversityUniversity of ZhejiangUniversity of ZhengzhouNanjing Normal UniversityNanjing UniversityShanxi UniversitySichuan UniversityHenan Normal UniversityHuazhong Normal UniversityWuhan UniversityZhengzhou UniversityZhongshan UniversityLiaoning UniversityHunan UniversityGuangshi University

Guangshi Normal UniversityHongkong UniversityChinese University of

Hongkong

Carnegie Mellon UniversityUniversity of Hawaii(University of Indiana)University of MinnesotaUniversity of RochesterUniversity of Washington

University of TokyoJoint Institute of Nuclear

Research, DubnaBudker Institute of Nuclear

Physics, NovosibirskGSIUniversity of BochumUniversity of GiessenUniversity of Turin

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BEPCII

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BEPCII: a high luminosity double–ring collider

SC RF

Beam magnets

Beam energy: 1.0-2.3GeV

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 Use many bunches

and SC mini-beta.

22 mrad crossing angle

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BEPCII/BESIII Commissioning

Linac

Nov. 18, 2007: First e+e- collisions without BESIII detectorMar. 2008: Collisions at 500 mA × 500 mA, Lumi.: 1 ×1032 cm-2s-1

Apr. 30, 2008: Move BESIII to IPJuly 18, 2008: First e+e- collision event in BESIIINov. 2008: Lumi. ~ 1.2 x 1032cm-2s-1, BESIII ~ 10M ψ(2S) eventsApr. 14, 2009 BESIII ~100M ψ(2S) eventsMay 14, 2009 BEPCII Lumi. ~ 3 x 1032cm-2s-1

Present: J/ψ – about 6 M/day

May 15, 2008: detector at IP;installing SC quads and beam pipe.

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Lattice optimization:matching with designed values

Debug systems: beam obstacles, vacuum leak, etc…

Increase current gradually :improve vacuum

Increase luminosity:Improve collision parameters

Beam current in BER 650mAJune 22, 2008 – Dec. 13, 2008

Beam current in BPR 700mAJune 26, 2008 – Dec. 13, 2008

BEPCII commissioning: continual improvement

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2323

Luminosity improvement

0.00E+003.00E+316.00E+319.00E+311.20E+321.50E+321.80E+322.10E+322.40E+322.70E+323.00E+323.30E+32

0 100 200 300 400 500 600 700

Current (mA)

Lum

inos

ity (c

m-2

s-1)

Lum2009Lum2008

★vx=0.51

vx=0.53

Peak Luminosity of 3.0*1032 achieved on May 13 with ~ 2×500mA and 71 bunches

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Parameters achieved in collision modeAchievedparameters design

BER BPREnergy (GeV) 1.89 1.89 1.89Beam curr. (mA) 910 650 700Bunch curr. (mA) 9.8 >10 >10Bunch number 93 93 93RF voltage 1.5 1.5 1.5∗νs @1.5MV 0.033 0.032 0.032βx

*/βy* (m) 1.0/0.015 ~1.0/0.016 ~1.0/0.016

Inj. Rate (mA/min) 200 e−/ 50 e+ >200 >50Lum. (1033cm-2s-1) 1 0.30

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BESIII

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BESIII Detector

Be beam pipe

SC magnetMagnet Yoke

MDC

CsI(Tl) calorimeter

TOF

RPC

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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 (19 axial, 24 stereo)

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

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MDC construction

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MDC wiring

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resrevoverallEntries 781908Mean -2.772e-05RMS 0.123

/ ndf 2χ 2234 / 154Prob 0p0 24.2± 5551 p1 1.416e-04± 9.471e-05 p2 0.00022± 0.07865 p3 23.5± 2245 p4 0.000456± -0.000392 p5 0.0008± 0.1854

Residual (mm)-1 -0.8 -0.6 -0.4 -0.2 -0 0.2 0.4 0.6 0.8 10

5000

10000

15000

20000

25000

30000

35000resrevoverall

Entries 781908Mean -2.772e-05RMS 0.123

/ ndf 2χ 2234 / 154Prob 0p0 24.2± 5551 p1 1.416e-04± 9.471e-05 p2 0.00022± 0.07865 p3 23.5± 2245 p4 0.000456± -0.000392 p5 0.0008± 0.1854

mμ=120σ

=80HT

=60, VLTV

Cosmic ray test of completed MDC

resolution 120 μm

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MDC calibration with Bhabhas

Eff. ~ 98%

Resol. 136 mm

● Layer 7● Layer 22

Wire resolution σP = 13.7MeV/c

= 0.7%

Beam related backgrounds

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Data/MC comparison - Bhabhas• Detailed simulation:

Resolution/efficiency of each cell as a function of drift distance, Q, HV, noise, entrance angle, …

• Future improvement: Need more data, better understanding, …

cos theta

drift distance (mm)

eff

σ(μ

m)

eff

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dE/dx resolutiondE/dx resol. = 5.80%

π

K p

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CsI(Tl) crystal calorimeter• Design goals:

– Energy: 2.5% @ 1GeV– Energy range: 20 MeV- 2 GeV– Spatial: 0.6cm @ 1GeV

• Crystals:– L = 28 cm (15 X0)– A = (5.2 x 5.2 – 6.4 x 6.4) cm2

– Barrel: 5280 w: 21564 kg– Endcaps: 960 w: 4051 kg– Total: 6240 w: 25.6 T

BaBar: 2.2% @ 1 GeV

BELLE: 2.2% @1 GeV

CLEO: 2.2% @1 GeV

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CsI(Tl) crystal calorimeter• Readout:

– 2 PDs + 2 preamps + 1 amp– PD: Hamamatsu S2744-08– 12480 PDs total (1 cm x 2 cm)– Preamp noise: < 220 keV

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Structure of EMC

Barrel EMC

Super module

Structure of endcap EMC

Endcap EMC

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EMC calibrationbarrel energy resol.

energy resolution for Bhabhas Position resolution for Bhabhas

4.4 mm

energy deposit for e+e- γγ

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Data/MC comparisone-

e+

π-

π+

p

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TOFCrucial for particle ID and for fast trigger.

• Barrel– 50mm x 60mm x 2320 mm

(inner layer).– BC408 – 2 layers – 88 in each– Radius from 810 to 930 mm.

• Endcap– 48 fan shaped pieces – each

end.– BC404

• PMT: Hamamatsu R5942fine mesh– 2 on each barrel scintillator– 1 on each endcap counter

• Resolution– Barrel: σT = 100 ps (one layer)– Endcap: σT = 110 ps

Barrel

Endcap

Length (cm) resolutionBESIII 240 90 psBELLE 255 90~100 psCDFII 279 100 ps

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Structure of TOF

Endcap TOF

Barrel TOF

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TOF calibration - BhabhasTOF Barrel: 103 psDesign:100 ps

Endcap TOF:125psDesign:110 ps

Barrel time resol. (ps) vs. z (mm)

Endcap time resol. (ps) vs. z (mm)

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TOF – MC Comparison

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Monitor the amplitude and time performance of each channel including PMTs and electronics. Concept:

Use fiber cable bundles (2 cables) to distribute light to barrel and endcap TOF counters.Use light splitter to illuminate one bundle at a time.

BESIII TOF Monitoring System

TOF endcap 48 fibers

TOF endcap 48 fibers

LaserDiode

Light splitter

TOF barrelPMT PMT

Ref. PMTsTo TOFelectronics

Fiber

TOF barrel 176 fibers

TOF barrel 176 fibers

Electronic switchFiber bundles

fiber

connectorBeam splitter

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Use PicoQuant 440M Laser Diode.– Simple to use and maintain.– Long lifetime (6 k hours at

full power).– Peak power: ~1W– Pulse width < 70 ps.– Wavelength 440 ± 10 nm.– Power stability 1% RMS.

BESIII TOF Monitoring System

PicoQuant LDH-P-440M

• State-of-the-art TOF monitoring system built by Hawaii.

• Major improvements:– Diode Laser– High quality multi fiber – fiber optic cables

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11/26/2010 45

TOF Monitoring

West Barrel TOF’s Tmean and Tsigma vs. PMT number.

NIM A593, 255 (2008).

10,000 laser pulses @ 1kHz

~75 ps

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11/26/2010 46

Barrel Time of Flight – last run.

Liu QianBarrel TOF’s Qm and Qsigma vs. PMT number.

~5 % resolution

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11/26/2010 47

History Database (BIE01)

Liu Qian

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11/26/2010 48

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 1.375mOuter radius 1.7mLength 3.91m

CoilMean radius 1.482mLength 3.52m

Cable dimension 3.7mm*20mmElectrical parameters

Central field 1.0TNominal current 3650AInductance 2H

Stored energy 10MJCold mass 3.6tonTotal Weight 15tonRadiation thickness 2X0

First of its kind built in China.

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11/26/2010 49

BESIII SC Magnet ProgressThermal insulation assembly

field mapping

wiring

installation

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2010-11-26 50

Muon Detector

Barrel + EndCap;RPCs as μ detector;Barrel: 9 layers – 72 modulesEndCap: 8 layers – 64 modules

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2010-11-26 51

Muon Detector

Barrel

Endcap

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2010-11-26 52

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 .• One dimension read-out strips (4 cm wide) - 10,000 channels. • Gas: Ar:C2H2F4:Isobutane = 50:42:8• HV voltage: 8000V

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53

Spatial resolution

MUON CounterEfficiency

Single counting rate

σ = 19 mm

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2010-11-26 54

Installation

Barrel EMC

MDC/TOF

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2010-11-26 55

April 2008 - Installation complete

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11/26/2010 56

May 2008 – At IR

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57

First collision event on July 19, 2008

13 M ψ’ events collected in 2008; 100 M in 2009

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2010-11-26 58

(Not even) preliminary resultsfrom 100 M ψ’ events

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59One month running.

Integrated luminosity

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6060

1.5*1032

2.16 2.29

2*500mA

Machine is stable, with data taking efficiency 15 times higher than BEPC. The peak luminosity keeps steadily increasing.

Luminosity vs beam current during the ψ(2s) run

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61

ψ’ energy scan

630 nb Energy spread: 1.45 MeVPeak cross section: 630 nb

Peak position = 3.684 GeVWorld average: 3.686 GeV

CM Energy (GeV)

cros

s se

ctio

n (n

b)

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62

Some physics signalsΛ signal

Red: K*

Blue: ⎯K*

0 0.05 0.1 0.15 0.2 0.25 0.30

500

1000

1500

2000

2500

π0 signal

0.4 0.45 0.5 0.55 0.6 0.65 0.70

50

100

150

200

250η signalBESIII preliminary

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63

EM transitions: inclusive photon spectrum

χc2χc1

χco

χc1,2 γ J/ψ

ηc

BESIII preliminary

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64

ψ(2S) π0hc, hc γηc

Part of BESIII data

BESIII preliminary

CLEOc: 25M

BES confirms the CLEOcobservation & will improve the precision of the hcproperties.

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65

ψ’ γγ l+l- : signals of χcJ, π0 and η

1cχ 2cχ0π

η Data: ~60M

BOSS6.4.3

m γψ

m γγ

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66

ψ(2S) γχcJBESIII preliminary

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67

ψ(2S) γπ0π0 ψ(2S) γηη

χc0 χc2

PDG 2. 43±0.20 0.71±0.08π0π0

CLEO-c* 2.94±0.07±0.35 0.68±0.03±0.08PDG 2.4±0.4 <0.5ηη

CLEO-c* 3.18±0.13±0.35 0.51±0.05±0.06

* CLEO-c arxiv:0811.0586Branching fractions (10-3)

BESIII preliminary

BESIII preliminary

Study of ψ(2S)→ γπ0π0 , γηη (η → γγ , π0 → γγ )

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68

Confirmation of the BESII observation: pp threshold enhancement−

0 0.1 0.2 0.3

/J ppψ γ→

BES III preliminaryψ(2S)→ ππJ/ψ

BES II/J ppψ γ→

PRL 91 (2003) 022001

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69

Confirmation of BESII observation: pp threshold enhancement

ppψ γ′ →

• FSI unlikely

No significant narrow strong enhancement near threshold(~2σ if fitted with X(1860))

ppψ γ′ →

Mpp (GeV)

BES III preliminary

PRL 99 (2007) 011802

BES II

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11/26/2010 70

Beam Energy Measurement

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2010-11-26 71

Tau mass measurements – current status

J. Z. Bai et al,

PRD53, 20 (1996)

92 citations

PDG (2008):1776.84 ± 0.17 MeV

(MeV)

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2010-11-26 72

Importance of τ Mass Measurement• M(τ) is fundamental parameter of SM.• M(e) and M(μ) are known to δM/M ~ 10-8 while M(τ) is

only known ~ 10-4.• Improved precision important to test universality:

• At present:

)1)(1(),(),(

)()(

52

γτ

μ

τ

μ

τ

μ

μ

τ δδυυμυυτ

ττ

++→→

⎟⎟⎠

⎞⎜⎜⎝

⎛=⎟

⎟⎠

⎞⎜⎜⎝

⎛W

e

e

mmFmmF

eBeB

mm

gg

0022.00006.1 ±=μ

τ

gg

Tests universality at 0.2% level.

A. Pich, arXiv0711.0028 (2007).

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2010-11-26 73

BESIII Beam Energy Measurement• BESIII can improve τ mass measurement but

precision is limited by knowledge of beam energy.• Fortunately method has been developed at BINP

using back scattered Compton photons produced by a CO2 laser beams on both the e+ and e- beams:

1. Beam energy ε determined by max energy (ωmax) of back scattered photons:

where ω0 is laser photon energy.2. Back scattered photons measured with High

Purity Ge (HPGe) detectors with precision of δε/ε ~ 1 x 10-5.

⎥⎥⎦

⎢⎢⎣

⎡++=

max0

2max 112 ωω

ωε em

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2010-11-26 74

BESIII Beam Energy Measurement3. Absolute calibration of energy scale done using

γ-active radionuclides.4. Expected resolution at BESIII Δε = 40 keV or

Δε/ε ~ 2 x 10-5.

measured at VEPP-4M

→ Δ mτ ≈ 0.13 MeV/c2 ; PDG08, Δ mτ ≈ 0.17 MeV/c2

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2010-11-26 75

BESIII Beam Energy Measurement•First BESIII upgrade.•Collaboration by IHEP, BINP, and U. of Hawaii.•Scheme:

Finish installation in fall 2009

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2010-11-26 76

BESIII Beam Energy Measurement

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2010-11-26 77

e+ e- physics at BESIII

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11/26/2010 78

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

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 4.030 0.6 0.32 1.0 × 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) samplesat BES3

A review (Yellow Book)of tau-charm physics:

arXiv:0809.1869.

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Study of X(1835) at BESIII using J/Ψ → γη’π+π-,η’ → ηπ+π- using 58 M events

At BES22 years

At BES32.5 days

mm(η’π+π-) mm(η’π+π-)

X(1835)X(1835) BES, PRL 95, 262001 (2005).

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11/26/2010 80

Testing LQCD: fDS

LQCD* (MeV) Experiment (MeV) DifferencefD 207 ± 4 205.8 ± 8.5 ± 2.5$ -fDS 241 ± 3 269.6 ± 8.3+ ~3σ

Vtd and Vts determined from B0 – B0 and BS – BS mixing results plusdecay constants from LQCD. Charm decay BRs provide a test of LQCD.

CLEOc uses tagged D’s from e+e- → ψ(3770) → D+D- and tagged DS’sfrom e+e- → DS

+ DS- + c.c. at E = 4170 MeV to measure fD and fDS.

22

222

2

||)1(8

)( cdD

lDlD

F VMm

MmfG

lD+

++ −=→Γ ++

πν

* HPQCD & UKQCD, PRL 100, 062002 (2008).$ CLEO, arXiv:0806.2112 (2009). Preliminary+ Belle, PRL 100, 241801 (2008); CLEOc, arXiv:0904.0985 (2009).

New physics?

How well can BESIII do with 20 fb-1 of data? About 2 years.fDS = 269.6 ± 3.0

see Roy Briere,arXiv:0904.0985

Yellow Book: arXiv:0809.1869.

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11/26/2010 81

Parameter Valuex (%) 0.89 +0.26

-0.27

y (%) 0.75+0.17-0.18

δ (0) 21.9+11.3-12.4

RD (%) 0.3348 ± 0.0086AD (%) -2.0 ± 2.4|q/p| 0.87+0.18

-0.15

φ (0) -9.1+8.1-7.8

δKππ (0) 33.0+25.9-26.6

see B. Golub,arXiv:0905.1021 (2009)

Yellow Book: arXiv:0809.1869.

D0 – D0 mixingMixing in the D sector has turned out to be much more interestingthan expected:

HFAG, arXiv:0808.1297.

Strong phase δ is important forextracting the CKM angle γ.

|q/p| and φ are consistent with no CPV.

CLEOc: δ = (22+11+9-12-11)0

(arXiv:0904.0985)

BESIII: For δ = 190, Δ(δ) = ± 90.

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11/26/2010 82

Current BESIIIVcd 4.8% ~ 1%Vcs 5.8% ~ 1%

Precision CKM measurementsDetermined from charmed meson leptonic andsemi-leptonic branching ratios:

Yellow Book: arXiv:0809.1869.

with 20 fb-1 data

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11/26/2010 83

Summary• BES has had a long productive history.

Future is BEPCII/BESIII.• Commissioning of BEPCII/BESIII

completed successfully: – Peak Luminosity of 3.0*1032 achieved.– 100 M ψ(2S) events obtained.– Currently running at J/ψ – 6 M events/day.

• Rich physics after CLEOc: 10 billion J/ψevents per year.

• BES is unique.

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11/26/2010 84

Extra Slides

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11/26/2010 85

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11/26/2010 86

DAQ

BESIII control room

Electronics room

Online computer room

Outside of DAQ

X terminal (PC×8)Online Histogram Display

Single Event Display

VME Crate� 17� / MDC

VME Crate� 16� / EMC

Online Farm� IBM Blade HS20 × 42�

Computer CenterTape Repository

To Intranet

VME Crate� 2� / TOF

VME Crate� 1� / MUC

VME Crate� 3� / TRG

Slow control switch

BEPCII switch

Web Server(X346)

File, Service and Manager Server

(X346 × 2)

4 Cisco 3750 StackCisco 3750

Storage Server(X346 × 2� 3TB)

FiberTwisted-pair

DAS10TB

event rate - 3kHzdata rate - 50 MB/sCPUs - ~1360 by end of 2008

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Particle ID SummaryTOF

Two layer barrel time-of flight,time resolution < 90ps

1 layer endcap TOF, time resolution ~ 110ps

dE/dx

Resolution ~ (6-7)%, 3σ K/π separation up to 600MeV/c

EMC

CsI crystal

Energy deposition, “shape” of shower

MUC

cut off momentum, as low as 500MeV

μ-ID efficiency > 90%, π punch-through < 5% @ 1GeV

Provide good e/μ/π/K/p separation in large solid angle coverage of BES3 detector (2)

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K/pi separationK/π likelihood combines TOF and dE/dx information.For K /π separation, efficiency > 90% and contamination rate < 10% @ 1GeV/c.e likelihood combines TOF, dE/dxand EMC information.Excellent electron-ID is expected in full momentum range.E/pi separation

K

BOSS6.3.3

π

Proton/Kaon separation

Particle ID