1. 1 BES III Wkshp10/01 I.Shipsey CLEO-c & CESR-c: A New Frontier in Weak and Strong Interactions Ian Shipsey, Purdue University  D o D o, D o  K -  + K-K- K+K+ ++  The CLEO Collaboration Albany, Carnegie Mellon, Cornell, Florida, Illinois, Kansas. Minnesota, Ohio-State, Pittsburgh, Purdue, Rochester, SMU, Syracuse, Texas PM, Vanderbilt, Wayne State

2. 2 BES III Wkshp10/01 I.Shipsey I am completely deaf please write down your questions. Pass them up to me I will read out your question before answering it.

3. 3 BES III Wkshp10/01 I.Shipsey CLEO-c : context ON OFF CESR/CLEO 1.3 16.0 6.7 34 KEKB/Belle 4.5 29.1 3.7 62 PEPII/BABAR (*) 3.4 34.1 4.1 74 SuperBaBar L =10 36 10 10 BB/year CLEO Major contributions to B/c/  physics But, no longer competitive. Last Y(4S) run ended June 25 ‘01 *BaBar/ Belle Numbers not updated since LP01 BB /year year

4. 4 BES III Wkshp10/01 I.Shipsey CLEO-c : the context Charm at threshold can provide the data to calibrate QCD techniques  convert CESR/CLEO to a charm/QCD factory LHC may uncover strongly coupled sectors in the physics that lies beyond the Standard Model The LC will study them. Strongly-coupled field theories are an outstanding challenge to theoretical physics. Critical need for reliable theoretical techniques & detailed data to calibrate them. This Decade The Future Example: The Lattice Complete definition of pert & non. Pert.QCD. Matured over last decade, can calculate to 1-5% B,D, ,  … Flavor Physics: is in “the sin2  era” akin to precision Z. Over constrain CKM matrix with precision measurements. Limiting factor: non-pert. QCD. “CLEO-c/CESR-C”

5. 5 BES III Wkshp10/01 I.Shipsey CLEO-c Physics Program flavor physics: overcome the non pert. QCD roadblock strong coupling in Physics beyond the Standard Model Physics beyond the Standard Model in unexpected places: CLEO-c: precision charm abs. branching ratio measurements CLEO-c: precise measurements of quarkonia spectroscopy & decay provide essential data to calibrate theory. CLEO-c: D-mixing, charm CPV, rare decays of charm and tau. CLEO-c will help build the tools to enable this decade’s flavor physics and the next decade’s new physics. Abs D hadronic Br’s normalize B physics Semileptonic decays: Vcs Vcd unitarity & form factors Leptonic decays : decay constants Tests QCD techniques in c sector, apply to b sector  Improved Vub, Vcb, Vtd & Vts

6. 6 BES III Wkshp10/01 I.Shipsey The parameters of the Standard Electroweak Model are: The 4 quark mixing parameters reside in CKM matrix The CKM Matrix & fermion masses and mixings Weak eigenstates Mass eigenstates * In SM, A, ,  are fundamental parameters Does the CKM fully explain quark mixing? CP Violation? To detect new physics in flavor changing sector must know CKM well Must overdetermine the magnitude and phase of each element

7. 7 BES III Wkshp10/01 I.Shipsey W  cs CKM Matrix Status l B  eiei 1 l D  l D  l B D 1 BdBd BdBd BsBs BsBs  Vud/Vud 0.1%  Vus/Vus =1%  Vub/Vub 25%  Vcd/Vcd 7%  Vcs/Vcs =16%  Vcb/Vcb 5%  Vtd/Vtd =36%  Vts/Vts 39%  Vtb/Vtb 29%   l Vud, Vus and Vcb are the best determined due to flavor symmetries: I, SU(3), HQS. Charm (Vcd & Vcs) and rest of the beauty sector (Vub, Vtd, Vts) are poorly determined. Theoretical errors on hadronic matrix elements dominate. e p n Free/bound eiei

8. 8 BES III Wkshp10/01 I.Shipsey Importance of measuring f D & f Ds : Vtd & Vts ~5% (lattice) 1.8%~15% Lattice predicts f B /f D & f Bs /f Ds with small errors if precision measurements of f D & f Ds existed (they do not) could substitute in above ratios to obtain precision estimates of f B & f Bs and hence precision determinations of Vtd and Vts Similarly f D /f Ds checks f B /f Bs (lattice)

9. 9 BES III Wkshp10/01 I.Shipsey Is related to at the same E  (corrections O(1/M)) Absolute magnitude & shape of form factors in PS  PS & PS  V : stringent test of theory. Key input to ultra precise (5%) Vub vital CKM cross check of sin2  Importance of absolute charm semileptonic decay rates b c u d HQS I assume unitarity Measure in D  l : calibrate lattice to 1% Lattice error on ~ 3% expected unquenched (Cornell/FNAL) Extract Vub at BaBar/Belle using calibrated lattice calc. of But: need absolute Br(D  l ) and high quality neither exist |f(q 2 )| 2 |V CKM | 2 // // Absolute rate gives direct measurements of Vcd and Vcs

10. 10 BES III Wkshp10/01 I.Shipsey Importance of precise absolute Charm Brs Stat: 3.1% Sys 4.3% theory 4.6% Dominant Sys:   slow (2.1%), form factors (1.4%) & B(D  K  ) (1.3%) V cb from zero recoil in B  D* + Vub/Vcb from at hadron machines requires: B(  c  pK  ) poorly known : 9.7% > B>3.0% at 90% C.L CLEO LP01 As B factory data sets grow, & theory improves charm Brs will become limiting systematic

11. 11 BES III Wkshp10/01 I.Shipsey Importance of precise absolute Charm Brs HQET spin symmetry test since D* +  + D o is most useful mode need D o /D + absolute rates Test factorization with B  DD s Need D s absolute Br Understanding charm content of B decay (n c ) Precision Z  bb and Z  cc (R b & R c ) At LHC/LC H  bb H  cc (h is any light hadron)

12. 12 BES III Wkshp10/01 I.Shipsey CESR-C Modify for low energy operation: add wigglers for transverse cooling (cost $4M) Expected machine performance:  E beam ~ 1.2 MeV at J/  ss L (10 32 cm -2 s -1 ) 3.1 GeV 2.0 3.77 GeV3.0 4.1 GeV3.6

13. 13 BES III Wkshp10/01 I.Shipsey CLEO-c Proposed Run Plan 2002: Prologue: Upsilons ~1-2 fb -1 each at Y(1S),Y(2S),Y(3S),… Spectroscopy, matrix element,  ee,  B h b 10-20 times the existing world’s data 2003:  (3770) – 3 fb -1 30 million DD events, 6 million tagged D decays (310 times MARK III) 2004: MeV – 3 fb -1 1.5 million D s D s events, 0.3 million tagged D s decays (480 times MARK III, 130 times BES) 2005:  (3100), 1 fb -1 &  (3686) –1 Billion J/  decays (170 times MARK III, 20 times BES II) CLEO-cCLEO-c A 3 year program

14. 14 BES III Wkshp10/01 I.Shipsey 1.5 T now,... 1.0T later 93% of 4   p /p = 0.35% @1GeV dE/dx: 5.7%  @minI 93% of 4   E /E = 2% @1GeV = 4% @100MeV 83% of 4   % Kaon ID with 0.2%  fake @0.9GeV 85% of 4  For p>1 GeV Trigger: Tracks & Showers Pipelined Latency = 2.5  s Data Acquisition: Event size = 25kB Thruput < 6MB/s CLEO III Detector  CLEO-c Detector

15. 15 BES III Wkshp10/01 I.Shipsey How well does CLEO III work? 1 st results from CLEO III data at LP01 B(B -  D 0 K - ) = ( 3.8 ±1.3) x10 -4 CLEOIII (2.9 ± 0.8) x10 -4 CLEO II Good agreement: between CLEO III & CLEO II Preliminary result using ~1/2 of the CLEO III data Clean K/  separation at ~2.5 GeV using RICH Rest of reconstruction technique similar to previous CLEO analyses

16. 16 BES III Wkshp10/01 I.Shipsey 1 st results from CLEO III data at LP01 Yield BR(B  K  )(x10 -6 ) B  K  CLEOIII CLEO(1999) Good agreement: between CLEOIII & CLEO II & with BaBar/Belle CLEO III works well (Preliminary)

17. 17 BES III Wkshp10/01 I.Shipsey A typical Y(4S) event: A typical  (3770) event:  (3770) events: simpler than Y(4S) events CLEO III detector has excellent tracking resolution excellent photon resolution maximum hermeticity excellent particle id flexible triggering high throughput DAQ The demands of doing physics in the 3-5 GeV range are easily met by the existing detector. The CLEO Collaboration has a history of diverse interests spread over b, c, tau, resonance and QCD studies & great enthusiasm for CLEO-c BUT: B Factories : 400 fb-1  500M cc by 2005, what is the advantage of running at threshold?

18. 18 BES III Wkshp10/01 I.Shipsey Advantages of Running on Threshold Resonances Charm events produced at threshold are extremely clean Large , low multiplicity Pure initial state: no fragmentation Signal/Background is optimum at threshold Double tag events are pristine –These events are key to making absolute branching fraction measurements Neutrino reconstruction is clean Quantum coherence aids D mixing and CP violation studies

19. 19 BES III Wkshp10/01 I.Shipsey Analysis Tools Our estimate of CLEO-C reach has been evaluated using simulation tools developed during our long experience with heavy flavor physics Fast MC simulation: TRKSIM Parameterized resolutions and efficiencies Standard event generators Excellent modeling of resolutions, efficiencies and combinatorial bkgd No electronic noise or extra particles Performance validated with full GEANT simulation (CLEOG) TRKSIM GEANT

20. 20 BES III Wkshp10/01 I.Shipsey Tagging Technique, Signal Purity  (3770)  DD  s ~4140  D s D s Charm mesons have many large branching ratios (~1-15%) High reconstruction eff  high net tagging efficiency ~20% ! D  K  tag. S/B ~5000/1 ! D s   (  KK) tag. S/B ~100/1 Beam constrained mass Anticipate 6M D tags 300K D s tags: MC Log scale! Log scale!

21. 21 BES III Wkshp10/01 I.Shipsey Absolute Branching Ratios ~ Zero background in hadronic tag modes *Measure absolute Br (D  X) with double tags Br = # of X/# of D tags # of D's is well determined Double tags are pristine  B/B Includes Stat, sys & bkgd errors Decay  s L Double PDG CLEOc fb-1 tags (  B/B %) (  B/B %) D 0  K -  + 3770 3 53,000 2.4 0.6 D +  K -  +  + 3770 3 60,000 7.2 0.7 D s  4140 3 6,000 25 1.9 CLEO-c sets absolute scale for all heavy quark measurements MC

22. 22 BES III Wkshp10/01 I.Shipsey Absolute Branching Ratios B(D 0  K -  + )% B(D s  B(D +  K -  +  + )% CLEO ALEPH PDG CLEO-c CLEO MARK III PDG CLEO-c CLEO PDG CLEO-c CLEO-c sets absolute scale for all heavy quark measurements

23. 23 BES III Wkshp10/01 I.Shipsey B(D +  l )/  D+ : f D+ |Vcd| B(D S  l )/  Ds : f Ds |Vcs| * Charm lifetimes known 1-2% * 3 generation unitarity Vcs, (Vcd) known to 0.1% (1.1%)  f D+ f Ds D meson Decay Constants Pseudoscalar decay constants: c and q can annihilate probability is  to wave function overlap |f D | 2 |V CKM | 2

24. 24 BES III Wkshp10/01 I.Shipsey D meson Decay Constants f Ds has been measured by several groups, best CLEO: There are also two measurements from LEP using D s    with large errors f D+ < 290 MeV @ 90% CL (Mark III) The rates we have used for our estimates are:

25. 25 BES III Wkshp10/01 I.Shipsey f Dq from Absolute Br(D q     Ds  Ds   D s  tag Compute MM 2 Peaks at zero for D s +    Expect resolution of ~M  o  ID not used helps systematic error MC If MM 2 > 0, candidate for   Require one additional charged track and no additional photons D+  D+   D +  K L  D +   Ds  Ds   Measure absolute Br (D q   ) Fully reconstruct one D (tag)/event

26. 26 BES III Wkshp10/01 I.Shipsey Summary of Decay Constant Reach Reaction ½  B / B ½  Vcq / Vcq CLEO-c  f/f PDG  f/f f Ds Ds+  Ds+   1.6%1%0.1%1.9%14% f Ds Ds+  Ds+   1.2%1%0.1%1.6%33% f D+ D+  D+   1.9%0.6%1.1%2.3%UL Reaction Signal  kgd  B/B Ds+  Ds+   1221165873.2% Ds+  Ds+   174001142.4% D+  D+   67230603.8% Branching Ratio Decay Constant

27. 27 BES III Wkshp10/01 I.Shipsey Current Status of D semileptonic decays Absolute Br’s poorly known dB/B- 5% - 73% Vcs f + (0) measured for D  Kl  0.79±0.01±0.04 (CLEO) Shape of f + (q 2 ), given by f + (0)/(1-q 2 /m p ) measured for D  Kl  m p =2.00±0.12±0.18 GeV 2  For D  K*l  ratios of form factors at q 2 =0  Neither good accuracy nor agreement among experiments  D  l  D  l  rates to ~20% accuracy

28. 28 BES III Wkshp10/01 I.Shipsey Semileptonic Decay Reconstruction Tagged events identify electron plus hadronic tracks Kinematics at threshold cleanly separates signal from background 25890 D 0  l D 0  l Excellent separation of D  l D  Kl despite B(D  Kl )~10B( D  l ) Tagged Events Low Bkgd! 1.0 fb -1 3730

29. 29 BES III Wkshp10/01 I.Shipsey Calibration of the Lattice Excellent kinematic resolution at threshold I. Can test form factor shape directly II. Using V cd from unitarity, can test normalization in D 0  l calibration good to ~1% CLEO-C D 0  l Lattice D 0  l compare to lattice prediction ex: hep-ph/0101023 FNAL etal Note: lattice error large ~15% on normalization now, but in future few % predicted

30. 30 BES III Wkshp10/01 I.Shipsey Pseudoscalar to Vector transitions Note: figure also applies to D  l. The four-fold joint angular decay distribution for D  K*/  l : Yet to be observed D +  - e + D +  K* 0 e + 1.0 fb -1

31. 31 BES III Wkshp10/01 I.Shipsey D +  K* 0 e form factor determination CLEO-C 12 K events/3 fb -1 S/B~20/1 Similarly, CLEO- will excel at Cabibbo suppressed modes D   e r v = V/A 1 r 2 = A 2 /A 1 CLEO-C 1.0 fb -1 From CLEO-c determined abs Br Lifetime and unitarity: E791 3K S/B 5/1 (FOCUS 40K S/B 8/1) E791 PDG Br, Lifetime & unitarity

32. 32 BES III Wkshp10/01 I.Shipsey CLEO-c Impact semileptonic dB/B CLEO-c PDG CLEO-c will make significant improvements in the precision with which each absolute charm semileptonic branching ratiois known

33. 33 BES III Wkshp10/01 I.Shipsey Determining Vcs and Vcd for the first time a complete set of charm PS  PS & PS  V absolute form factor magnitudes and slopes to a few% with ~zero bkgd in one experiment. If theory passes the test….. Many internal cross checks, in the semileptonic sector invoke unitarity. Can combine with leptonic decays eliminating VCKM  (D +  l  (D +  l  independent of Vcd Test rate predictions at ~4% Test amplitudes at 2% Both tests important.Stringent test of theory!  (D s  l  (D s  l  independent of Vcs Test rate predictions at ~ 4.5%

34. 34 BES III Wkshp10/01 I.Shipsey Determining Vcs and Vcd Absolute branching ratios + lifetimes : Tagged  B/B (stat)  /  (stat+sys) CLEO-c PDG 77670 0.4% 1.2%  Vcs /Vcs = 1.6% 16% 11190 1.0% 1.5 %  Vcd /Vcd =1.7% 7% II) Use CLEO-c validated lattice + B factory B  lv for ultra precise Vub R=Vcd /Vcs  R/R 1.2% CLEO-c 2 % FOCUS gain confidence to (I) determine Vcs and Vcd from: Includes tracking EID and lifetime errors Includes 3% Theory Error on rate- A challenge! Take ratio of like initial states form factors differ only by SU(3) breaking, no lifetime dependence, some cancellation of expt. Systematics + no requirement for theory to predict absolute rate

35. 35 BES III Wkshp10/01 I.Shipsey Unitarity Constraints |Vud| 2 + |Vus| 2 + |Vub| 2 = 1 ?? With current values this test fails at 2.5  |Vcd| 2 + |Vcs| 2 + |Vcb| 2 = 1 ?? With CLEO –c can test to ~3% Make the second row sensitivity comparable to the 1 st row Compare ratio of long sides to 1.3% Also major contributions to Vub Vcb Vtd Vts |VubVcb*| |VudVcd*| |VusVcs*| cu triangle

36. 36 BES III Wkshp10/01 I.Shipsey Excess of  over e fakes Background measured with electrons CLEO signal 4.8fb -1 –Search for D s * -> D s , D s ->  –Directly detect  Use hermeticity of detector to reconstruct –Backgrounds are LARGE! Precision limited by systematics of background determination –FDs Error ~23% now (CLEO) –400 fb -1 ~6-9% FDs at a B factory Scale from CLEO analysis Compare to B factories f Ds CLEO-c Mass Difference  M GeV/c Ds  Ds    M=M   M 

37. 37 BES III Wkshp10/01 I.Shipsey Compare to B Factories D o  K -  + Method: Detect D* +  + D o, when D o  K -  + and D o  anything. Problem: Systematic Error due to background extrapolation  B/B = 3.6% Expect limited improvements 2-3%  is  between thrust axis & slow  + (4 of 8 intervals shown) CLEO CLEO-c D o  K -  + Double tagged thrust Slow pion 

38. 38 BES III Wkshp10/01 I.Shipsey BaBar 400 fb -1 Current Comparison between B factories & CLEO-C Systematics & Background limited CLEO-c 3 fb -1 Statistics limited abcdefghi

39. 39 BES III Wkshp10/01 I.Shipsey Compare to B Factories Systematics & background limited. 2.3% 1.7% 0.7% 1.9% 0.6% 2-2- 0  2% 6 – 9 Statistics limited. UL 14%

40. 40 BES III Wkshp10/01 I.Shipsey DD mixing exploit coherence: for mixing: no DCSD.  r D =  [ (x 2 +y 2 )/2] < 0.01 @ 95%CL (K  K , Kl,Kl ) CP violating asymmetries Sensitivity: A cp < 0.01 Unique:L=1,C=-1 CP tag one side, opposite side same CP CP=±1   (3770)  CP=±1 = CPV CP eigenstate tag X flavor mode K + K -  D CP   (3770)  D CP  K -  + Measure strong phase diff.  cos  ~0.05 CF DCSD Needed for  from B  DK Rare charm decays. Sensitivity: 10 -6 Probes of New Physics  (3770)  DD(C = -1)  (4140)  DD (C = +1) Gronau, Grossman, Rosner D mix & DCPV suppressed in SM – all the more reason to measure them

41. 41 BES III Wkshp10/01 I.Shipsey  and  Spectroscopy –Masses, spin fine structure Leptonic widths for S-states. –EM transition matrix elements run on  resonances winter ’01-summer’02 ~ 4 fb -1 total Uncover new forms of matter –gauge particles as constituents –Glueballs G=|gg  –Hybrids H=|gqq  Requires detailed understanding of ordinary hadron spectrum in 1.5-2.5 GeV mass range. Probing QCD Calibrate and test theoretical tech. Study fundamental states of the theory J/  running 2005 Confinement, Relativistic corrections Wave function Tech: f B,K  B K f D{s) Form factors  Verify tools for strongly coupled theories  Quantify accuracy for application to flavor physics

42. 42 BES III Wkshp10/01 I.Shipsey Gluons carry color charge: should bind! CLEO-c 1 st high statistics experiment covering 1.5-2.5 GeV mass range. find it or debunk it! Radiative  decays are ideal glue factory: Gluonic Matter X  c c¯ CLEO-c: 10 9 J/   ~60M J/   X Partial Wave analysis Absolute BF’s: ,KK,pp, ,… 1 perfect initial state perfect tag glue pair in color isosinglet Huge data set Modern detector 95% of 4  coverage But, like Jim Morrison, glueballs have been sighted too many times without confirmation....

43. 43 BES III Wkshp10/01 I.Shipsey The f J (2220) :A case study Glueballs are hard to pin down, often small data sets & large bkgds BES (1996) MARKIII (1986) ?? LEAR 1998 pp   s   s Crystal barrel : ssss ssss 

44. 44 BES III Wkshp10/01 I.Shipsey f J (2220) in CLEO-c? Anti-search in Two Photon Data:  f J  2220  –CLEO II:   B  f J (2220)  /K S K S  < 2.5(1.3) eV –CLEO III: sub-eV sensitivity – Upsilonium Data:  (1S): Tens of events 5000–  850032pp 530023KSKSKSKS 1860046K+K-K+K- 1300018  3200074  CLEO-CBES CLEO-c has corroborating checks: 2 3            

45. 45 BES III Wkshp10/01 I.Shipsey Inclusive Spectrum J/   X Inclusive photon spectrum a good place to search: monochromatic photons for each state produced Unique advantages of CLEO-c + Huge data set +Modern 4  detector (Suppress hadronic bkg: J/   X) +Extra data sets for corroboration ,  (1S): Lead to Unambiguous determination of J PC & gluonic content

46. 46 BES III Wkshp10/01 I.Shipsey + HESR at GSI Darmstadt p p complementary, being proposed: physics in 2007? Comparison with Other Expts China: BES II is running now. BES II --> BES III upgrade BEPC I --> BEPC II upgrade, ~10 32 2 ring design at 10 33 under consideration (workshop 10/01) Physics after 2006? if approval & construction go ahead. HALL-D at TJNAL (USA)  p to produce states with exotic Quantum Numbers Focus on light states with J PC = 0+-, 1+-, … Complementary to CLEO-C focus on heavy states with J PC =0++, 2++, … Physics in 2007+ ? being proposed BES III Complimentary To CLEO-c

47. 47 BES III Wkshp10/01 I.Shipsey Additional topics  ’ spectroscopy (10 8 decays)  ’ c h c ….     at threshold (0.25 fb -1 ) measure m  to ± 0.1 MeV heavy lepton, exotics searches  c  c at threshold (1 fb -1 ) calibrate absolute BR(  c  pK  ) R=  (e + e -  hadrons)/  (e + e -   +  - ) spot checks If time permits Likely to be added to run plan

48. 48 BES III Wkshp10/01 I.Shipsey Crucial Validation of Lattice QCD: Lattice QCD will be able to calculate with accuracies of 1-2%. The CLEO-c decay constant and semileptonic data will provide a “golden,” & timely test. QCD & charmonium data provide additional benchmarks. (E2 Snowmass Working Group) CLEO-c Physics Impact (what Snowmass said) Imagine a World where we have theoretical mastery of non- perturbative QCD at the 2% level Now Theory errors = 2%

49. 49 BES III Wkshp10/01 I.Shipsey Knowledge of absolute charm branching fractions is now contributing significant errors to measurements involving b’s. CLEO-c can also resolve this problem in a timely fashion Improved Knowledge of CKM elements, which is now not very good. CLEO-c Flavor Physics Impact (what Snowmass said) VcdVcsVcbVubVtdVts 7%16%5%25%36%39% 1.7%1.6%3% 5% B Factory Data & CLEO-c Lattice Validation (Snowmass:E2 Working Group) CLEO-c data and LQCD PDG

50. 50 BES III Wkshp10/01 I.Shipsey Next Steps CLEO-C workshop (May 2001) : successful ~120 participants, 60 non-CLEO Informational sessions with funding agencies & HEPAP (April/May ‘01) : very positive response Snowmass working groups E2/P2/P5 : acclaimed CLEO-c CESR/CLEO Program Advisory Committee Sept 28. endorsed CLEO-c Proposal submission to NSF on October 15 2001 See http://www.lns.cornell.edu/CLEO/CLEO-C/ for project description We welcome discussion and new members

51. 51 BES III Wkshp10/01 I.Shipsey The CLEO-c Program: Summary Powerful physics case Precision flavor physics – finally Nonperturbative QCD – finally Probe for New Physics Unique: not duplicated elsewhere Highest performance detector to run @ charm threshold Flexible, high-luminosity accelerator Experienced collaboration Optimal timing LQCD maturing Flavor physics of this decade Beyond the SM in next decade The most comprehensive & in depth study of non-perturbative QCD yet proposed in particle physics Direct: Vcs Vcd & tests QCD techniques aids BABAR/Belle/ CDF/D0/BTeV/LHC-b with Vub,Vcb,Vtd,Vts

52. 52 BES III Wkshp10/01 I.Shipsey Backup Slides

53. 53 BES III Wkshp10/01 I.Shipsey CESR-C Luminosity governed by: Long damping times: without artificial radiation aids: –--> wigglers to decrease  –Wigglers being prototyped –2T over 5cm (SC) –Cost ~ 5M$ –Decrease  * (underway) A* Cross section at collision point N = Number of particles  = Lorentz factor r = vert/horiz beam size  = beam beam parameter  *= external focussing L (10 32 cm -2 s -1 ) 3.6 3.0 2.0  s 4.1 GeV 3.77 GeV 3.1 GeV Expected machine performance:  E beam ~ 1.2 MeV at J/  L = 1.3 x 10 33 @Y(4S) L~E b 4 L~E beam 2