Open Charm Everard CORDIER (Heidelberg) Grako meeting HD, April 28, 2006Everard Cordier.
UHM Physics and Astronomy - Charm in China: BEPCII/BESIIIfah/bestalks/SLAC... · 2010. 11. 26. ·...
Transcript of UHM Physics and Astronomy - Charm in China: BEPCII/BESIIIfah/bestalks/SLAC... · 2010. 11. 26. ·...
11/26/2010 1
Frederick A. HarrisFrederick A. HarrisUniversity of HawaiiUniversity of Hawaii
Charm in China: BEPCII/BESIIISLAC Experimental Seminar
June 30, 2009
11/26/2010 2
OUTLINEOUTLINE
• Introduction: physicsof tau charm region
• BEPCII• BESIII• ψ(2S) (not even)
preliminary results•Beam energy
measurement• BESIII physics• Summary
IHEP
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.
11/26/2010 4
• 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:
11/26/2010 5
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
11/26/2010 6
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
11/26/2010 7
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
11/26/2010 8
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-)
11/26/2010 9
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).
11/26/2010 10
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.
11/26/2010 11
Latest R result:
BES, PLB 677, 239 (2009).
error ~ 4%
11/26/2010 12
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
2010-11-26 13
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…
11/26/2010 1411/26/2010 14
• 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).]
11/26/2010 1511/26/2010 15
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).
11/26/2010 16
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.
11/26/2010 17
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
11/26/2010 18
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
2010-11-26 19
BEPCII
11/26/2010 20
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
11/26/2010 21
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.
2222
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
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
2424
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
11/26/2010 25
BESIII
11/26/2010 26
BESIII Detector
Be beam pipe
SC magnetMagnet Yoke
MDC
CsI(Tl) calorimeter
TOF
RPC
2010-11-26 27
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
11/26/2010 28
MDC construction
2010-11-26 29
MDC wiring
2010-11-26 30
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
31
MDC calibration with Bhabhas
Eff. ~ 98%
Resol. 136 mm
● Layer 7● Layer 22
Wire resolution σP = 13.7MeV/c
= 0.7%
Beam related backgrounds
32
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
33
dE/dx resolutiondE/dx resol. = 5.80%
π
K p
11/26/2010 34
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
11/26/2010 35
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
11/26/2010 36 36
Structure of EMC
Barrel EMC
Super module
Structure of endcap EMC
Endcap EMC
37
EMC calibrationbarrel energy resol.
energy resolution for Bhabhas Position resolution for Bhabhas
4.4 mm
energy deposit for e+e- γγ
38
Data/MC comparisone-
e+
π-
π+
p
2010-11-26 39
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
2010-11-26 40
Structure of TOF
Endcap TOF
Barrel TOF
41
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)
42
TOF – MC Comparison
11/26/2010 43
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
2010-11-26 44
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
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
11/26/2010 46
Barrel Time of Flight – last run.
Liu QianBarrel TOF’s Qm and Qsigma vs. PMT number.
~5 % resolution
11/26/2010 47
History Database (BIE01)
Liu Qian
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.
11/26/2010 49
BESIII SC Magnet ProgressThermal insulation assembly
field mapping
wiring
installation
2010-11-26 50
Muon Detector
Barrel + EndCap;RPCs as μ detector;Barrel: 9 layers – 72 modulesEndCap: 8 layers – 64 modules
2010-11-26 51
Muon Detector
Barrel
Endcap
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
53
Spatial resolution
MUON CounterEfficiency
Single counting rate
σ = 19 mm
2010-11-26 54
Installation
Barrel EMC
MDC/TOF
2010-11-26 55
April 2008 - Installation complete
11/26/2010 56
May 2008 – At IR
57
First collision event on July 19, 2008
13 M ψ’ events collected in 2008; 100 M in 2009
2010-11-26 58
(Not even) preliminary resultsfrom 100 M ψ’ events
59One month running.
Integrated luminosity
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
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)
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
63
EM transitions: inclusive photon spectrum
χc2χc1
χco
χc1,2 γ J/ψ
ηc
BESIII preliminary
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.
65
ψ’ γγ l+l- : signals of χcJ, π0 and η
1cχ 2cχ0π
η Data: ~60M
BOSS6.4.3
m γψ
m γγ
66
ψ(2S) γχcJBESIII preliminary
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 )
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
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
11/26/2010 70
Beam Energy Measurement
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)
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).
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
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
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
2010-11-26 76
BESIII Beam Energy Measurement
2010-11-26 77
e+ e- physics at BESIII
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.
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).
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.
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.
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
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.
11/26/2010 84
Extra Slides
11/26/2010 85
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
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)
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