1. High Intensity Electron Positron Accelerator Facility (HEPAF) Zhengguo Zhao Collaborative Innovation Center for Particle Physics and Interaction University of Science and Technology of China 1

2. High Energy Physics in China: Post BEPCII Chinese high energy physicists, led by the Chinese High Energy Association, has been exploring the future project. Projects under discussing by four working groups - Circular Higgs Factory (CEPC-SppC) - Z Factory (ZF) - Electron Heavy Ion Collider (EIC) - High Intensity Electron Positron Accelerator Facility(HEPAF) Whichever project is going to be chosen, a new site needs to be found  A site with sustainable development potential is crucial for high energy physics in China. 2

3. Project for Big Science Scientific significance: Convincing scientifically excellent  Key science questions? Project plan: Convincing been well planed– Scope, cost, schedule, key technology, experts… Public support: Scientific community, public society, government - Good positive environment - Good cases with project specific benefits - Good connection with public medium and government 3

4. Physics at  -c Energy Region Hadron form factors Y(2175) resonance Mutltiquark states with s quark, Zs MLLA/LPHD and QCD sum rule predictions Hadron form factors Y(2175) resonance Mutltiquark states with s quark, Zs MLLA/LPHD and QCD sum rule predictions Light hadron spectroscopy Gluonic and exotic states LFV process Rare and forbidden decays Physics with  lepton Light hadron spectroscopy Gluonic and exotic states LFV process Rare and forbidden decays Physics with  lepton XYZ particles Physics with D mesons f D and f Ds D 0 -D 0 mixing Charm baryons XYZ particles Physics with D mesons f D and f Ds D 0 -D 0 mixing Charm baryons _ Precision  QED  a   charm quark mass extraction. Hadron form factor(nucleon,  Possible new resonance which are not yet discovered. R scan 4 R=  (e + e -  hadron)/  (e + e -   +  - )

5. HEPAF: Accelerator Peak luminosity: 100 BEPCII (0.5/1x10 35 cm -2 s -1 at E cm =4 GeV Energy region: E cm =2–7 GeV Polarization available on one beam? Symmetric machine with low currents and crab waist solution for the interaction region Interdisciplinary mode for - ring: compatible with synchrotron radiation facility (SRF) - linac: free electron laser (FEL) 5

6. Possible Schematic Layout (Qin Qing, IHEP) Option 1Option 2 6

7. Beam Parameters (Qin Qing) Beam energy (GeV) 3.0 Revolution frequency (MHz)0.302 Circumference (m) 992.8Harmonic number1656 Coupling factor 0.005β x, y @ IP (mm) 1000, 1.0 Emittance (nm.rad) 10Beam-beam parameter0.06 Bunch length (mm) 10Number of bunch540 Momentum compaction 0.001Bunch current (mA)5.0 SR energy loss/turn (MeV) 0.716Beam current (A)2.7 Synchrotron tune 0.0128SR power (MW)1.93 RF voltage (MV) 2.0Energy spread8.12E-4 RF frequency (MHz) 500.06Luminosity (cm -2 s -1 )1.05E35 (Lattice and other related AP studies are under way) 7

8. Requirement To The Detector 8 Efficient event triggering, exclusive state reconstruction and tagging – high efficiency and resolutions for charged and neutral particles Best possible solid angle coverage High resolution for charged particles: [0.05, 1.6] GeV Good PID: [0.05, 2] GeV Good e,  detection eff. and energy resolution: [0.02,2.5] GeV Good vertex detection: 50  m

9. MDC PXD/SSD PID-barrel PID-endcap EMC Superconducting magnet (0.7-1 T) York/Muon IP 3~6 cm 10 cm 15 cm 85 cm 105 cm 135 cm 185 cm 245 cm 120 cm140 cm190 cm240 cm300 cm 20  Detector MDC  xy =130  m dE/dx<7%,  p /p =0.5% at 1 GeV PXD Material budget ~0.15%X 0 / layer  xy =50  m PID  /K (and K/p) 3-4  separation up to 2GeV/c EMC Energy range: 0.02-2GeV At 1 GeV  E (%) Barrel(Cs(I): 2 Endcap (Cs): 4 MUD  /  suppression power >10

10. Organization 10 HIEPF Physics& Software Physics& Software Detector Vertex Tracker EMCAL PID MUD SCM Collectivity Electronics Trigger DAQ Theory Generator simulation Calibration Reconstruction Calibration Reconstruction Infrastructure Civil engineering Civil engineering Technical supporting Technical supporting Computing network data service Computing network data service Safety Environment Safety Environment Accelerator Injector Ring

11. 11

12. HEPAF Study Time Line 20132014201520162017 Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 Kick-off collaboration forming Workshops Feasibility study Review CDR, R&D  TDR?

13. Summary HEPAF is one of the possible options for high energy physics in China. We need to be well organized with clear task force. Regular working group meeting is crucial. Calling for more people to join the effort. Next workshop: June, Dec. 13

14. Extra Slides 14

15. SuperKEKB 15 STCF Factory Luminosity Trend of e + e - Collider There has never been a e + e - collider that directly work at tau-charm energy region with peak luminosity above 10 33. It would be a great pity if STCF were going to be missed in the HEP history BEPCI ?

16. New Physics Case No new physics has been found at the LHC so far – compatible with our understanding of flavour. Important to directly look for new types of process, e.g. cLFV from indirect searches, even provide data for constraining models 16

17. Lepton Flavour Violating (LFV) 17 cLFV processes sensitive to New Physics (NP) through lepton-lepton coupling ,  anomalous decays  e conversion Anomalous magnetic moment PSI Mu2e

18.  The process e + e -  +  - , dominant background source at  (4S), does not contribute below 2E  4m  /  3  4.1 GeV. The favorable kinematical condition and the use of polarization can allow an UL(SuperB near threshold in 1-2 years) ≤ UL (SuperB@Y(4s) in 5-6 yrs). It will take 12-15 yrs to SuperBELLE). EE EE EE 10.6 GeV4.25 GeV4.0 GeV 18

19. 19 Diptimoy Ghosh

20. 20 Diptimoy Ghosh

21. Precision EW 21 Mike Roney, Dec 2012 See: https://agenda.infn.it/getFile.py/access?contribId=241&sessionId=64&resId=0&materialId=slides&confId=4442https://agenda.infn.it/getFile.py/access?contribId=241&sessionId=64&resId=0&materialId=slides&confId=4442

22. V us 22 Emilie Passemar τ decays could provide a competitive measurement of V us + many other topics covered

23. Proton Form Factor: IG E I/IG M I space-like JLAB e - p  e - p ΙG E Ι/ΙG M Ι time-like 23 Complete picture of the nucleon structure requires spacelike and timelike measurements!

24. XYZ Particles (How many more and what are they?) Y(4660) Y(4630) Y(4008) BELLE: PRL99, 142002 BESIII: Primary BESIII: PRL(2013) 252001 Z c +- (3900)   +- J/  e + e -   X(3872) 24

25. Drift chamber (MDC) Small cell, 43 layer Gas He/C 3 H 8 =40/60  xy =130  m, dE/dx~6%  p /p = 0.5% at 1 GeV ECAL calorimeter CsI(Tl): L=28 cm (15X 0 ) Energy range: 0.02-2GeV At 1 GeV  E (%)  spatial (mm) Barrel: 2.5 6 Endcap: 5 9 Time-of-flight (TOF) Plastic scintillator    barrel): 90 ps    endcap): 110 ps Muon counter Resistive plate chamber Barrel: 9 layers Endcaps: 8 layers  spatial : 20 mm 1 T Super conducting magnet Data acquisition Event rate: 4 kHz Data size: 50 MB/s “Grid” computing CPU: 3200 core Storage: 2.2 pB BESIII Detector 25 RO channels: 10 4 Cost: 200 M RMB

26. Data Samples Accumulated with BESIII 26  DsDsDsDs cccc 5.0 pb -1 4 points for R &QCD 1.2x10 9 5x10 8 2.9 fb -1 4040 0.4 fb -1 4040 0.4 fb -1 4260 1 fb -1 4260 1 fb -1 4360 0.5 fb - 1 4360 0.5 fb - 1 Not well explored region Need high statistical data Need dada 26

27. Data Samples Accumulated with BESIII 27  DsDsDsDs cccc 5.0 pb -1 4 points for R &QCD 1.2x10 9 5x10 8 2.9 fb -1 4040 0.4 fb -1 4040 0.4 fb -1 4260 1 fb -1 4260 1 fb -1 4360 0.5 fb - 1 4360 0.5 fb - 1 Not well explored region Need high statistical data Need dada 27

28. Super-B -> Tau Bare Cost For Tau-Charm only: C(M€) ≈148.3 + 0.133 L(m) 300 < L(m) < 1200 Very preliminary bare cost below 190 MEuros 28

29. Facilities for Particle Physics in China 29 Cosmic Ray Observatory ? ? ? ?