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E2 Snowmass Report

E2 Snowmass Report. Convenors:. Charge: consider the future of low-energy electron-positron colliders and evaluate developments needed to make incisive instruments practical. Gustavo Burdman, Joel Butler, Ian Shipsey & Hitoshi Yamamoto. ¾ of the E2 convenors can hear.

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E2 Snowmass Report

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  1. E2 Snowmass Report • Convenors: Charge: consider the future of low-energy electron-positron colliders and evaluate developments needed to make incisive instruments practical. Gustavo Burdman, Joel Butler, Ian Shipsey & Hitoshi Yamamoto

  2. ¾ of the E2 convenors can hear. • I am completely deaf, please write down your questions. • Pass them up to me • I will read out your question before answering it.

  3. Low Energy e+e – Colliders: The Physics case Flavor physics, B, D, K, & . Does the standard model account for quark mixing & CPV? Measuring the magnitudes and phases of all CKM matrix elements (most remain poorly determined) is a sensitive probe for New Physics. In addition rare (loop) decays probe physics at high mass scales. Radiative corrections. Testing the consistency of the SM requires a variety of measurements for which radiative corrections play a crucial Role. Examples: (I) g-2/2 , (II) electroweak natural relations (Higgs mass bound) Non-perturbative QCD is a great challenge to theoretical physics. LHC may uncover strongly coupled sectors in beyond the SM physics. Critical need: reliable theoretical techniques & detailed data to calibrate them: ,  spectroscopy, decay constants,form factors provide the data to calibrate QCD now

  4. Advantages of e+e- colliders e+e- annihilation produces clean final states, with low backgrounds i.e.favorable S/N. Low energy e+e- colliders can reach high luminosity: witness the stunning success of PEP-II KEK-B. The quantum #’s of the initial state are known, quantum coherence is a powerful tool.

  5. Scope of the E2 Report • A snapshot of the low-energy e+e- colliders landscape: Super B factories Status: proposed CP in K system Rare K decays new physics Precision R CLEO-c /CESR-c BEPCII PEP-N KLOE at DAFNE 109 Z Flavor Physics: D,  New physics Precision tests non-perturbative QCD CP in B system New physics Status: proposed Status: running Status: proposed 1.0 1.2-3.1 3 –510.6 91.2  B -charm

  6. Report Methodology:Evaluation of the physics case Develop & evaluate the physics case jointly with P2 For each type of factory: Identify the outstanding questions that heavy-flavor factories address Evaluate the contributions from existing and potential experiments using other instruments. Critically assess the competitive advantages and disadvantages of e+e- colliders Outline a comprehensive experimental program and estimate the integrated luminosity required to carry it out. Determine what special detector capabilities are required to achieve the scientific goals, What detector R&D issues arise?

  7.  Factory Physics DAFNE: symmetric e+e- Ebeam= 510 MeV Target Luminosity 5 x 1032 cm –2s -1 Current Luminosty 2.5 x 1031 cm –2s -1 (x 20 low) Luminosity arrow(pb-1) • KLOE (KLOng Experiment) • Measurement to test CP and CPT violation with K ( Double Ratio, Interferometry) requires 1010 KLKS • Rare K decays • Measurement of interest for ChPT: (K Semileptonic Decays & Kl4, h/h’ mixing , K 3p… ) Measurement of s(pp) at low energy : important for g-2 • F radiative decays (f0g, a0g, hg, h’g ) 5000 1000 100 20 Focus on these 12/01 today

  8. DAFNE Two independent machines intersection at  25 mrad Bunch length 3 cm Horizontal size 2 mm Vertical size 0.02 mm Working condition now : 800 mA stored into 50 e+/e- bunches Delivered Luminosity : 1.3 pb-1 per day (sustained) 2000: 30 pb-1 2001: 55 pb-1 18/7 200pb-1 by end of year

  9. The KLOE Detector d=4m DC He gas, minimize MS & KL regeneration EMC: Pb/SciFi

  10. CPV in the K system ’/ comparision  Factory to Fixed Target At a  factory double ratio and interferometric methods are complementary to fixed target appraach. KLOE goal ’/ to ~2 x10-4 BUT Hadronic uncertainities dominate measurements of ’/ (5000 pb-1)

  11. Rare K Decays comparision of  Factory to Fixed Target The important measurements in Kaon physics are now rare Decays: B(K++ )~9 x 10-11 B(KL0) ~3 x 10-11 Measurements driven by high flux KLOE  factories have unique & desirable features but unlikely to provide enough flux to challenge hadron machines for K  Few year window for KLOE to push KL0 sensitivity into a region where new physics may be observed Kopio /KAMI+ KAMI+ KAMI+ +KAMI not approved

  12. PEP-N Physics • Proposed novel extension to PEP-II e+e- at 1.2  3.1 GeV • Broad range of physics: • R measurement • evolution of EM • hadronic contribution to g-2 • Nucleon form factors • Other baryon form factors • Meson form factors • Vector meson spectroscopy • Multihadron channels • * interactions Focus on this h a r d o n s e+ * e- Hadron loop Hadronic vacuum polarization:

  13. Importance of R #1: Precision Electroweak Measurements/Fits The SM can be defined by GF Mz EM(Mz2). The latter is the least well known and limits accurate prediction of MHiggs Evolution of  EM 1 < s < 3 GeV crucial, goal: R2% reduces had(5) x2 R had(5): CLEO CMD2, KLOE CLEO-c BESIII S PEP-N

  14. Importance of R #1: Precision Electroweak Measurements/Fits had limits precision on extraction of sin2w & hence constraint on MH MH ~30 GeV PEP-N R2% improves Constraint MH ~10 GeV Giga-Z goal x10 (sin2w) requires had~ 5 x 10-5 R1% MH ~4 GeV Pre (& post Higgs discovery) constant improvement in R is a goal of low energy e+e- colliders

  15. Importance of R #2 Testing the consistency of the SM requires a variety of Measurements for which radiative corrections play a crucial Role. Example: g-2/2 Current errors:= { 3 4 62}x10-11 Hadronic vacuum polarization cannot be calculated from 1st principles: phenomenolgical models (QCD + ) combined with R. Bulk of error comesfrom s < 2.5 GeV SUSY 2.6  New physics? Final goal of expt ±40 x 10-11reduce SM error by 50%, rely on e+e- data only: R  ~2% 2m<s<2.5 GeV

  16. PEP-N Collider

  17. PEP-N Collider VLER: new e- ring 0.1 to 0.8 GeV PEP II LER low E beam of PEPII Parasitic non-interfering running with Babar e- energy: variable 0.1 to 0.8 GeV at < 80 mA e+ energy: fixed 3.1 GeV at 2140 mA (from LER) Luminosity: 1031 at 0.8 GeV e-

  18. PEP-N Detector requirements for R: hermetic detector, reconstruct complete event • cm = 0.8 • event rate: < 1 Hz • Low p tracks: He TPC • magnet: 0.1-0.3 T vertical B field (must NOT disturb LER and HER) • Pb/sci.fi EM calorimeter excellent E/E, t/t • n, nbar, : Fe/Scint Had cal • Detector similar to KLOE, • no new technology: entirely • feasible

  19. Proposed PEP-N Schedule Summer 2002 PEP-N Proposal approved Summer 2003 Injector gun, linac and transport lines installed LER and HER mods October 2003 First injector beam tests Summer 2004 VLER ring installed Detector magnet & Detector installed October 2004 First VLER injected beam tests January 2005 First collisions

  20. E2 Conclusion on PEP-N The determination of R in this energy range is of particular importance, and is timely.Rstat is negligible, however no clear demonstration that Rsys to 2% (dominated by acceptance) is achievable. Studies stimulated by Snowmass are ongoing: ex: A CLEO-c 10 9J/ run  precision determination of J/ br’s. Useful for PEP-N precision determination of acceptance. Detector design, based on KLOE, although still evolving is sound and involves no new technology Collaboration ~65 people is small, more members are sought. LOI review 9/01. 1st data 2005? Conclude:The physics program of PEP-N is well defined, important and unique and can be accomplished in 5 years. Control of systematic errors needs to be evaluated.

  21. CLEO-c • Now that the asymmetric B factories have achieved high luminosity, CLEO proposes to focus on measurements in the 3.5-5.0 GeV region, including • Charm Decay constants fD, fDs • Charm Absolute Branching Fractions • Semileptonic form factors • Vcd & Vcs • QCD studies including • Charmonium and bottomonium spectroscopy • Glueball and exotic searches • Measurement of R between 3 and 5 GeV, via scans • Measurement of R between 1 and 3 GeV, via ISR • Search for new physics via charm mixing, CP violation and rare decays • t decay physics

  22. CLEO Run Plan 2002: Prologue: Upsilons ~1-2 fb-1 each at Y(1S),Y(2S),Y(3S),… Spectroscopy, matrix element, Gee, B hb 10-20 times the existing world’s data 2003: y(3770) – 3 fb-1 30 million events, 6 million tagged D decays (310 times MARK III) C L E O - c 2004: – 3 fb-1 1.5 million DsDs events, 0.3 million tagged Ds decays (480 times MARK III, 130 times BES) 2005: y(3100), 1 fb-1 y(3686) –1 Billion J/y decays (170 times MARK III, 20 times BES II) A 3 year program

  23. Advantages of Running on Threshold Resonances • Charm events produced at threshold are extremely clean • Double tag events are pristine • These events are key to making absolute branching fraction measurements • Signal/Background is optimum at threshold • Neutrino reconstruction is clean • Quantum coherence aids D mixing and CP violation studies

  24. 1.5 T now,... 1.0T later 83% of 4p 87% Kaon ID with 0.2% p fake @0.9GeV 93% of 4p sp/p = 0.35% @1GeV dE/dx: 5.7% p @minI 93% of 4p sE/E = 2% @1GeV = 4% @100MeV CLEO III Detector = CLEO-c Detector Trigger: Tracks & Showers Pipelined Latency = 2.5ms Data Acquisition: Event size = 25kB Thruput < 6MB/s 85% of 4p For p>1 GeV

  25. 1st results from CLEO III datafor LEPPHO 2001 Yield BR(BK)(x10-6) BK CLEOIII CLEO(1999) (Preliminary) Good agreement: CLEOIII:II/II.V

  26. The CLEO-III Detector Silicon vertex detector may be replaced with wire vertex chamber Lower solenoid field strength to 1 T from 1.5 T (machine issues) The dE/dx and Ring Imaging Cerenkov counters are expected to work well over the CLEO-c momentum range Electromagnetic calorimeter works well and has fewer photons to deal with Triggers will work as before Minor upgrades may be required of Data Acquisition system to handle peak data transfer rates CESR conversion to CESR-c will be discussed in summary talk of working group M2 (next speaker) Modifications and Issues CLEO-III works well in this energy range and at these rates with little modification

  27. Tagging Techniques Signal Purity D mesons have many large Br’s (~1-15%) with high reconstruction eff. Tagging efficiency based on several modes is 20%. S/B = 5000/1! Single Tag ~ Zero background in hadronic tag modes *Measure Br (D X) by Br = # of X/# of D tags # of D's is well determined Double Tag

  28. Example: Ds+  m+n • Fully reconstruct one D • Require one additional charged track and no additional photons • Compute MM2 Peaks at zero for Ds+  m+n decay. • No need to identify muon-helps systematic error • Can identify electrons to check background level • Expect resolution of ~Mpo Ds mn 2 (Now: ±35%)

  29. CLEO-c Charm Decay Measurements

  30. Absolute Branching Ratios CLEO ALEPH PDG CLEO-c CLEO MARK III PDG CLEO-c B(D0K-p+)% B(D+  K- p+p+)% CLEO PDG CLEO-c CLEO-c sets absolute scale for all heavy quark measurements B(Ds fp) %

  31. Semileptonic Decay Reconstruction • Tagged events: identify electron plus hadronic tracks ( muons not used) • Kinematics at threshold cleanly separates signal from background • Use to separate signal from background 1.0 fb-1 25890 3730 Excellent separation ofDl Dkl despite B(Dkl )~10B( Dl)

  32. CLEO-C Impact on dB/B CLEO-c PDG

  33. A Selection of Other Key CLEO-c Physics On y’, can do charmonium Spectroscopy, e.g.: 1P1,hc’ New Physics in D decays: Mixing: CP violation: ~1% Rare Decays: many modes with UL~1-10x10-6

  34. Comparison with BABAR & BES BEPC-II /BES-III a proposed double ring machine L = 2 x 10 33 (x10 CESR-c) to come online in ~2005 - if approved. Will make an important contribution as data improves and theory sharpens

  35. Comparison between B factories & CLEO-C CLEO-c 3 fb-1 BaBar 400 fb-1 fD Current (not in %)

  36. CLEO-c Physics Impact • 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,” and timely test. QCD and charmonium data provide additional benchmarks. • 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 Lattice Validation CLEO-c data and LQCD • The potential to observe new forms of matter – glueballs, hybrids, etc –and new physics- charm mixing, CP violation, and rare decays provides a discovery component to the program

  37. B Physics Buras • The unitarity triangle construction summarizes a set of overconstrained measurements of the quark sector of the Standard Model Goal: I. measure the sides and angles of the unitarity triangle inconsistency  New Physics II.Search for rare decays to the theory limit  New Physics • What are the ultimate experimental and theoretical limits on • the precision of such tests? • If new phenomena are found at LHC/LC….. can precision heavy quark (or ) physics help elucidate the situation?

  38. Models that may modify the Unitarity Triangle • Supersymmetry • 43 phases, 80 constants • MSSM - with or without new flavor structure • Strongly coupled EW sector • Fourth generation • Flavor changing Z0 couplings • Multi-Higgs doublet models • Left-right symmetric models • Extra d-type singlet quarks • Non-commutative geometry • Extra dimensions • + many more • There is a substantial literature on how these models could change the observed pattern of CP asymmetries, modify rare decay rates and angular distributions, etc.

  39. B physics Experiments Running, Planned & Proposed E2 goal compare physics reach of running & planned facilities to proposed facilities e+e- : =1nb Babar/Belle 500 fb-1 = 1x 109 B (cumulative) 2005 B+ B0 only at Y(4S) Hadronic: = 100/500 b BTeV/LHC-b (~2007) (2-10)x1011 B/ 107s B+ B0 Bs Bc b Method: (I) benchmark modes ex: sin2, (II) particular strengths There are three new proposed facilities: Giga-Z at the LC and Super B factories at KEK & SLAC. How do they compare to the the planned and existing facilities?

  40. Giga-Z at LC as a B Factory LEP/SLC made significant contributions to B physics The LC may run at the Z0 pole: Br(Z  bb) =15% @ L = 5 x 1033 50 days for 109 Z 109 Z 3 x 108 B’s possible within normal LC running 1010 Z 3 x 109 B’s 150 days/yr 3-5 yrs: dedicated facility Two options Comparison to existing e+e- B fac: Comparable statistics Large boost: separation of two B’s & better decay length resolution Large AFB with polarized beams good initial state charge tagging All B flavors produced B+ B0 Bs /\b Comparison to LHC-b/BTeV Much lower B rate But: all B’s triggered & reconstructed Clean environment

  41. Giga-Z as a B Factory Paucity of Giga-Z specific studies, mainly repetiton of B-factory/BTeV Particular strengths of Giga-Z: polarized /\b (unique) tests chirality of bs: b Also possible at BTeV/LHC-b Bs mixing xs ~ 60 (109 Z) resolution limit xs ~120 hadron machines xs ~80 bs probes new physics (best U.L:ALEPH) Giga-Z br/br ~4% at 109 Z (~10 evts at e+e-), not possible @ BTeV/LHC-b Conclusion: Giga Z strengths need careful assessment, (ongoing) 3-5 yrs for Giga-Z = 1 yr BTeV/LHC-b sin2 precision

  42. e+e- Super B factories (SBF) History: Workshop on Super B Factories “Beyond 1034” June 2000 Michigan http://www.physics.purdue.edu/10E34/ Calls for: (3 x1035 – 3 x 1036) cm–2s-1 John seem Follow up session on Super B factories at BCP4 Japan 2/01 : ~1036 http://www.hepl.phys.nagoya-u.ac.jp/public/bcp4/ SUPERBABAR working group formed 5/01, lead by D. Hitlin nucleus of E2 SBF subgroup at Snowmass. http://fermi.phys.uc.edu/HyperNews/get/forums/SuperBABAR.html

  43. e+e- Super B factories (SBF) Plans at KEK : SUPERKEKB L= 1 x 10 35 (Oide/Ohnishi) Several options understudy: upgrade existing machine or new machine both in asymmetric format Plans at SLAC SUPERBABAR L = 1 x 10 36 cm –2 s –1(Seeman) Preliminary studies indicate it may be possible to build an e+e- asymmetric collider in PEPII tunnel or using SLC arcs (See summary talk from M2 for details of both machines)

  44. Comparison of BTeV and SuperBABAR @ 1036 At 1036 # B0 B+ reconstructed in interesting modes is about the same for e+e- and BTeV L 36 10 3600 L 36 10 600

  45. CKM Reach super B factories & hadron facilities SBF numbers based on BABAR experience need simulations to estimate signal efficiencies & bkgds so that the comparison to BTeV/LHC-b is on an equal footing (Table compiled by SBF E2 subgroup & E2 convenors)

  46. Rare B decay Reach super B fac. & hadron facilities All numbers are per year except current B factories (cumulative Through 2005) Best measurement Greater reach? Hadronic: B e+e-: s, , ,K* 7.2K/- Including additional rare b and Bs modes not in Table 1035 reach < BTeV/LHCb 1036 reach ~ BTeV/LHCb 4.4 k /4.5k 10/11 2/2 (Table compiled by SBF E2 subgroup & E2 convenors)

  47. Technical Challenges At 1036 short beam lifetime requires continuous injection. Loss rates x1000 greater than at present However sensitivity to lost particles depends on lattice,IR design & detector design It is important to perform simulations with a realistic IR and lattice a.s.a.p. Simple scaling from BABAR experience has been used to estimate doses and to develop the following detector conceptual design: A BABAR SUPERBABAR reason for change Silicon Si pixels occupancy Drift Chamber Si tracker (or TPC) accumulated charge DIRC superDIRC remove water standoff box ECAL CsI(Tl) LSO long decay time not rad hard IFR (K L0 ) IFR’ RPC’s sci fi (occupancy)

  48. A compact, high field detector for 1036 IFR Fe + scint. fibers Compact DIRC SVT 2 Ly pixel 3 Layer Si strip 4 Layer Si Strip tracker LSO EMC G. Eigen 3T Coil

  49. Conclusions I  factories have unique & desirable features but unlikely to provide enough flux to challenge hadron machines for K  PEP-N : The physics program is well defined,important & unique and can be accomplished in 5 years. Control of systematic errors for R needs to be evaluated. CLEO-c : x400 increase in D data at threshold. Crucial validation of Lattice QCD, HQET, ChPTHH, … A factor 4-12 improvement in key abs. branching fractions Significant improvement in CKM element precision (x 5-10) c sector (x2-8 ) in b sector (in conjunction with B expts.) Discovery potential : new physics: D mixing & CPV rare D,  decays new forms of matter (glueballs/hybrids) accelerator, detector & collaboration in place: 3 year program

  50. Conclusions II Giga Z strengths: b polarization, xs reach, rare decays with , , 0,Vub. Needs careful assessment, (ongoing). 3-5 yrs at Giga-Z = 1 year BTeV/LHC-b sin2 precision 1035 e+e- B factory : strengths rare decays with ’s , 0 Vub 3 yrs at 1035 = 1 year BTeV/LHC-b sin2 precision 1036 e+e- B factory: At 300x current luminosity and assuming detector efficiency can be maintained, would be complementary to LHC-b/BTeV for rare decays, superior for decays with ’s , 0 & Vub, comparable for , , , but not . Limited Bs and no Bc & b compared to LHCb and BTeV. Implement Lattice/IR designs a.s.a.p. for detailed background studies, especially background due to continuous injection. If backgrounds prove tractable an R&D program on the machine & detector should be initiated.

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