1. CLEOC/BESIII— New Frontiers of -C Physics
Z.G. Zhao
University of Michigan, Ann Arbor, MI, USA
IHEP of CAS, Beijing, China
I . CLEOC/CESRC and BESIII/BEPCII
II. Physics Over View
III. Current Status
Suggestions to BESIII
V. Summary

2. Current Operating e+e- CollidersB 
VEPP-2M
DAFNE
VEPP-2000
BEPC
BEPCII
CESR-C
KEKB
PEPII
VEPP-4M
CESR
Factory
Peak Luminosity
(1/1030 cm-2s-1)

3. CESR-C CESR Modify CESR for low-energy operationCESR-C;
Add wigglers for transverse cooling

4. CLEOC State of art detector, well understood
1.5 T now, T later
93% of 4p
sp/p =
dE/dx: 5.7%
83% of 4p
87% Kaon ID with 0.2% p
93% of 4p
sE/E = =
Trigger: Tracks & Showers
Pipelined
Latency = 2.5ms
Data Acquisition:
Event size = 25kB
Thruput < 6MB/s
85% of 4p
For p>1 GeV
State of art detector, well understood
Replace silicon strip tracker with 6 layer inner drift chamber

5. BEPC II — Double Ring Ecm=2~5.16 GeV Luminosity~1033 cm-2s-1IP e - RF SR +
Ecm=2~5.16 GeV
Luminosity~1033 cm-2s-1
(optimized at 3.68 GeV)

6. BESIII Must be competitive to CLEOC Almost a completely new detector
Magnet:
T existing BESII magnet
- 1 T Super conducting magnet
BESIII
CDC: xy=50 m
MDC: xy=130 m
sp/p =
dE/dx=6%
TOF:
T = 80 ps Barrel
100 ps Endcap
EMCAL:
sE/E =
z = 0.5 cm/E
Muon ID: 9 layer RPC
Trigger:Tracks & Showers
Pipelined; Latency = 2.4ms
Must be competitive to CLEOC
Almost a completely new detector
Data Acquisition:
Event size = 12kB
Thruput ~50 MB/s

7. Physics Features in -c Energy Region
CESRC
BEPCII
(3770)

8. Physics Features in -c Energy Region
Transition between smooth and resonances, perturbative and non-perturbative QCD
Rich of resonances, charmonium and charmed mesons.
New type of hadronic matter are predicted in the region, e.g. glueball and hybrid
Threshold characteristics, large , low multiplicity, pure initial state, S/B optimum

9. A Typical Hadronic Event in CLEOIII/BESII
Hadronic events from BESII
R scan
CLEO

10. Key Issues in Particle Physics
Verify the SM
The test of the SM has been dominating exp. HEP for about three decades.
Establish and test strong-coupled, nonperturbative quantum field theories
Still the foremost challenge in modern physics
The effects of the strong interactions non PQCD permeate every
experimental measurement involving quarks and are an obstacle in
almost every attempt to extract precision electroweak physics from data.
Probe new physics beyond the SM
It’s of profound importance to
systematically study the weak interactions that mix quark and lepton flavor
complete understand QCD
Precision data is badly needed to enable a comprehensive mastery over
non PQCD and to calibrate and validate the theoretical technology

11. CKM and LQCD

12. CKM Matrix
CKM, fundamental parameters in nature that reflect the flavor
and generation mixing, is induced by weak interaction.
Cannot be predicted within the SM and must be determined
by experiment.
Charm decays is a unique laboratory to determine directly Vcd
and Vcs, indirectly Vub and contribute to Vcb.
D decay
Mixing
B decay

13. Lattice QCD
LQCD is the only compete definition of QCD. It includes both perturbative and non perturbative QCD.
LQCD is not a model.
- The only parameters are s and the quark masses.
- Relates B/D physics to Y/ physics and to glueball
physics to …
Predict to ~15% accuracy for a wide range of masses (include glueball and hybrid), decay constants, form factors for many conventional hadrons.
The challenge for LQCD is to demonstrate reliability at the level of a few percent accuracy require wide range of highly precision experimental data

14. LQCD Predictions for Glueball Masses
Lowest Lying States:
Scalar 0++, M ~ 1.6 GeV
Tensor 2++, M ~2.3 GeV
Pseudoscalar, M ~ 2.5 GeV
QCD is not understood until we
understand gluonic degree of
freedom in the spectrum,
glueballs and hybrids.

15. The CLEOC Program Act I (2003): (3770) 3 fb-1
30M events, 6M tagged D decays
Act II (2004): ~ 4100  3 fb-1
1.5M DsDs, 0.3M tagged Ds decays
Act III (2005): (3100)  1 fb-1
1 billion J/ decays
Focused data samples to collect and clear
physics goals to reach.

16. Precision Standard Model Tests
Absolute hadronic charm branching ratios with 1-2% errors
fD+ and fDs at ~2% level
Semileptonic decay form-factors (few % accuracy)
Contribute to CKM Measurements

17. Absolute Branching Ratios
Decay Mode PDG CLEOC
(dBr/Br %) (dBr/Br %)
D0  Kp
D+  Kpp
Ds  fp
Set absolute scale for all heavy quark
measurement

18. CLEOC Expected Precision in Decay Constants
fD+ and fDs
LQCD can predicts fB/fD and fBs/fDs. Measure fD, fDs give fB and fBs, thus determine Vt d and Vts
Similarly measure fD/fDs checks fB /fBs
CLEOC Expected Precision in Decay Constants
Decay Mode Decay Constant fDq/fDq (%)
D+  + fD
Ds+  + fDs
Ds+  + fDs

19. Semileptonic Form Factors
Semileptonic decay severe as excellent laboratory to study
both weak and strong interaction
e.g. D+  Kl
Decay Mode / CKM Element CKM Precision
D0  K-e+ % |Vcs| %
D0  -e+ % |Vcs| %
Weak physics
Strong physics

20. How Much CLEOC Can Improve CKM
Present
After CLEOC

21. Other Interesting Topics

22. Test of the SM and QCD in Continuum
R scan 2-5 GeV (2~3%)
Evaluating QED, a’ mHiggs, high precision test of SM, hunting for new physics beyond the SM; structures of high mass  region
Large hadronic events sample at point (2-3GeV)
- Multiplicity: second binomial momentum
R2 [nch(nch-1)/nch2] = 11[1-cs(s)]/ NLQCD
- =-ln(p/s) distribution for charged particles MLLA, LPHD
- Hadronic events shape: thrust, transverse moment distribution
pQCD, power correction
- (e+e- 2/4 /K); e+e-  /K+X;
Polarized parton density, S/U universality; quark and glue fragmentation (combine with J/ data)
Charmed baryons
pQCD, string fragmentation, HQE and duality

23. Relative Uncertainty Contribution to a and (Mz2) without BES R Data

24. Relative Contribution in Magnitude and Uncertainty
BESIII,CLEOC
CMD,SND
KROE
CLEO

25. Second Order Momentum
Peak Position of 

26. MeanThrust
S/U Universality

27. J/ and (2S) Decays J/ decays Search for new forms of matter
- Glueballs: h(1440), f0(1370), f0(1500), f(1700), fJ(2000)
- Exotic mesons: 0--, 0+-, 1-+, 2+- p1(1400), p1(1600),
Study of excited baryonic states (N*, *, *, *... )
(2S) decays
Search for missing or unconfirmed states: 1P1, c’
Measure hadronic branching fraction ( puzzle)
Measure radiative transition rate
Study of cJ states
Best laboratory to elucidate a tricky situation; unique
opportunity for QCD studies and new level of understanding

28. New Study of the  Lepton
Lower limit on m at sub 10 MeV level
Determination of m 0.1 MeV
Precision measurement of key Br. (,0)
Measure Michel parameters
Direct search for non-SM physics

29. Searches and New Physics
D0D0bar mixing
CP violation in , J/, (2S) decays
Lepton flavor violating processes
e.g. J/’, =e, , 
Rare decays
--X, e-G, -……. J/DX
Taking advantage of threshold production,
much high statistics and low background

30. Why CLEOC in B Factory Era
Some important measurements at B’s are limited by systematical uncertainty
CLEOC enjoys threshold production, large production cross section, low multiplicity, low BG, high S/B. But limited by statistics

32. Why BESIII in CLEOC Era? BESIII BEPCII CESRC
CLEOC: 2003: y(3770) -- 3 fb-1; 30 M
2004: fb-1; 1.5M DsDs
2005: y(3100) -- 1 fb-1; 1 Billion J/y
BESIII

33. Why BESIII in CLEOC Era?
Three years CLEOC program does not cover all the interesting physics in c energy region
- 2-3 GeV, 2-3% R scan in 2-5 GeV
- physics of  and (2S)
- Charmed baryon
Need higher statistics for searches (glueball, exotica), rare decay, D0-D0bar mixing, CP and further improve the precision measurements.
New discoveries needs to be confirmed or continued. New type of matters, need high statistics to study it’s properties.

34. Is BESIII Worth Doing? YES
if L~1033 cm-2s-1 and BESIII is competitive to CLEC, and the commissioning is not too late
Otherwise NOT really

35. Possible Side Product Cosmic ray experiment
e.g. low energy (E<10 GeV)  spectrum. Important for SupperK  experiment
L3CBESIII-C (cosmic exp.)

36. Suggestions to BESIII/BEPCII
BEPCII: L~1033 cm-2s-1; BESIII must be compatible to CLEOC
Learn experiences and lessons from the other successful labs. Utilize ONLY mature technology.
Don’t use highest version of hardware and software.
Build a workable, reliable system has the highest priority. Don’t try to design fancy systems which is difficult for one to learn and use.
Set up an active international collaboration. A team that can committed and devoted to the project is essential
Select or train qualified experts in charge of each sub-system is of profound importance for the success of the project

37. Suggestions to BESIII/BEPCII
Prototype, R&D work should be done as early as possible
Additional attention should be paid to
- overall detector/ machine integration
- alignment and monitoring
- IR region
- trigger
- detector simulation, database, computing and network
- better thermo isolation in detector hall (~ C)
- better gas supply system (shorten the transportation
distance, less T)

38. CLEOC/CESRC Status CESR/CLEO Program Advisory Committee
Sept Endorsed CLEO-c
Proposal submission to NSF (October 15,2001)
Site visit on Jan/Feb 2002: Endorsed CLEO-c
Expect approval in Summer of 2002
Wiggler prototype test successfully in vertical cryostat; now being installed in its horizontal cryostat. Will be put into CESR in July
Start building six layers CDC
Cost $3.5 M

39. Status of BEPII/BESIII
Feasibility Study Report of BEPC II has been submitted to the funding agency.
Technical Design Report of BEPC II to be submitted soon.
Construction expected d to be started in 2003 and commissioning in 2007.
Cost $75 M (~1/3 for BESIII)

40. Interesting Schedule of CLEOC/BESIII
CLEOC phys. run ?
BESII
BESIII
Construction
Engineer & phys. run
MARKIII
CLEOC/CESRC:
Wisely seizes the great opportunity; perfectly fills the gas in the
frontier of weak and strong interactions
BESIII/BEPCII:
Nature extension. Will be a unique frontier of c physics for a
decade after CLEOC.

41. Typical Peak Luminosity of CESR-C, BEPC and BEPCII
(1/1030 cm-2s-1)
L(BEPCII)  3 L(CESR-C)  50L(BEPC)

42. Typical Dada Samples Proposed
Additional Data for other physic topics
Charm baryons at threshold, e.g.
+- pairs at threshold
R scan in 2-5 GeV; large hadronic event sample in 2-3 GeV

43. Summary
Physics in tau-charm energy region is sill very rich in the B’s era.
CLEOC/CESRC, a smart decision that seizes great physics opportunities, is opening a new era of understanding weak and strong interaction.
BESIII/BEPCII, an nature extension of the only high energy physics base in China, will continue BESII and CLEOC’s mission to deepen the understanding of weak and strong physics, play a unique role in the precision test of SM, QCD and search for new physics in c sector.

44. Tanks to Maury and CLEOC collaboration for the
Information about CERSC/CLEOC
Weiguo Li and BES collaboration for the
information about BESIII/BEPCII
Fred for many useful discussion about BES’s
future