1. CEPC/SppC with ILC ( FCC) J. Gao Institute of High Energy Physics Beijing, CAS Panel discussion, Nov. 5, at LCWS 2015 Nov. 2-6, 2015, Whistler, Canada http://cepc.ihep.ac.cn/

2. Important reminds  CEPC-SppC is proposed in Sept. 2012, right after Higss discovery at CERN by LHC in July 2012  “C” in CEPC doesn’t stands for China, but “Circular” and mostly for high energy physics “Community”. CEPC is of the Community, by the Community and for the Community  ILC, CEPC, FCC(ee) are proposed tools to produce Higgs (+ others) through e+e- collision  ILC, CEPC, FCC(ee) have many common technologies and task force overlapes  The succeed of the community is the succeed of any of them  In Oct. 30, 2015, Chinese government cleared next five year plan and beyond on science with the following statement: “Actively propose and lead the international science plans and big scientific projects ( 积极提出并牵头组 织国际大科学计划和大科学工程 ) ”

3. Ways towards future HEP 1 ） Linear colliders ： ILC-CLIC from Higgs energy to 5TeV (Support and Participation) 2 ） Circular Colliders ： CEPC-SppC e+e- Higgs factory-pp collider at 50~100TeV (Host) Precision @ e+e- collider Energy frontier @ pp collider  Higher precision  Higher energy e+e- LTB CEPC (50km-100km ) Boostr(50Km-100km ) SppC (50-100Km)

4. 4 Introduction to CEPC+SppC (Pre-CDR) LTB : Linac to Booster BTC : Booster to Collider Ring BTC IP1 IP3 e+e- e+ e- Linac (240m) LTB CEPC Collider Ring(54Km ) Booster(54Km ) BTC Medium Energy Booster(4.5Km) Low Energy Booster(0.4Km) IP4 IP2 SppC Collider Ring(54Km) Proton Linac (100m) High Energy Booster(7.2Km)

5. CEPC/SppC on Site (Example)

6. CEPC Design – Top Level Parameters 6 ParameterDesign Goal Particlese+, e- Center of mass energy240 GeV Integrated luminosity (per IP per year)250 fb -1 No. of IPs2 SPPC Design – Top Level Parameters 6 ParameterDesign Goal Particlesp, p Center of mass energy70 TeV Integrated luminosity (per IP per year)(TBD) No. of IPs2  one million Higgs from 2 IPs in 10 years Z, W, tt (100km) are not optimization goal as that of Higgs!, but with considerations

7. ParameterUnitValueParameterUnitValue Beam energy [E]GeV120Circumference [C]m54420 Number of IP[N IP ] 2SR loss/turn [U 0 ]GeV3.11 Bunch number/beam[n B ] 50Bunch population [Ne] 3.71E+11 SR power/beam [P]MW51.7Beam current [I]mA16.6 Bending radius [  ] m6094 momentum compaction factor [  p ] 3.39E-05 Revolution period [T 0 ]s1.82E-04Revolution frequency [f 0 ]Hz5508.87 emittance (x/y)nm6.12/0.018  IP (x/y) mm800/1.2 Transverse size (x/y) mm 69.97/0.15  x,y /IP 0.116/0.082 Beam length SR [  s.SR ] mm2.17 Beam length total [  s.tot ] mm2.53 Lifetime due to Beamstrahlungmin80 lifetime due to radiative Bhabha scattering [  L ] min52 RF voltage [V rf ]GV6.87RF frequency [f rf ]MHz650 Harmonic number [h] 117900 Synchrotron oscillation tune [ s ] 0.18 Energy acceptance RF [h]%5.98 Damping partition number [J  ] 2 Energy spread SR [  .SR ] %0.13 Energy spread BS [  .BS ] %0.08 Energy spread total [  .tot ] %0.16nn 0.23 Transverse damping time [n x ]turns78Longitudinal damping time [n  ]turns39 Hourglass factorFh0.692Luminosity /IP[L]cm -2 s -1 2.01E+34 Main parameters for CEPC (Goal of CDR)

9. ParameterValueUnit Circumference52km Beam energy35TeV Dipole field20T Injection energy2.1TeV Number of IPs2 (4) Peak luminosity per IP1.2E+35cm -2 s -1 Beta function at collision0.75m Circulating beam current1.0A Max beam-beam tune shift per IP0.006 Bunch separation25ns Bunch population2.0E+11 SR heat load @arc dipole (per aperture)56W/m SppC main parameters (Goal of CDR)

10. 258 authors from 45 institutions in 9 countries International review has been done in the beginning of 2015 http://cepc.ihep.ac.cn/preCDR/volume.html

11. To better know the potential performance of CEPC/SppC with respect to machine length (50,70,100km), Collding energies (W, Z, H, tt), Layout(single ring, double rings, partial double rings), colliding angles (head-on, crab-waist), etc. Polarized colliding beams... More on CEPC parameters and potentials

12. ParametersZ-poleW-pole E[GeV]45.580 C[km]50 N IP 2 P[MW]0.891.854.061012.520.845.8 U 0 [GeV]0.620.59 I[mA]14.2229.665.216.8213577 NbNb 481002204860100220 N e [10 11 ]3.093.65 x [nm·rad]4818.68 y [pm·rad]9636 β x [m]0.8 β y [mm]1.2 σ x [µm]196122.25 σ y [µm]0.340.208 ξxξx 0.0320.056 ξyξy 0.0280.049 σ s [mm]2.65 hourglass factor0.68 L[10 34 cm −2 s −1 ]0.2240.4661.0250.821.021.73.74

13. ParametersHiggs Factory Beam energy E[GeV]120 Circumference C[km]5070100 Number of IP N IP 2 Bending radius ρ[km]6.0948.611 SR power/beam P[MW]50 SR loss/turn U 0 [GeV]3.012.131.67 Beam current I[mA]16.623.430.3 Bunch number N b 48114220 Bunch population N e [10 11 ]3.6132.87 Horizontal emittance x [nm·rad]6.126.366.8 Vertical emittance y [pm·rad]21.22018.2 Betatron function at IP-vertical β y [mm]1.2 1 Betatron function at IP-horizontal β x [m]0.8 Transverse beam size σ x [µm]7071.373.8 Transverse beam size σ y [µm]0.160.1550.135 Beam-beam parameter ξ x 0.1120.090.08 Beam-beam parameter ξ y 0.0740.0620.055 Bunch length σ s [mm]2.65 Hourglass factor0.68 0.63 Luminosity L[10 34 cm −2 s −1 ]1.822.152.75

14. Possible scheme to produce polarized positrons (W. Gai) To store and collide the injected polarized beams in CEPC are not so obvious

15. 15 Parameter choice for SPPC (Potential) …… (F. Su et al)

16. Parameter choice for SPPC (Potential) (F. Su et al)

17. CEPC Pretzel Scheme 48 bunches / beam, 96 parasitic collision points (~ 500 m spacing) Horizontal separation, no off-center orbit in RF section One pair of electrostatic separators for each arc (green) One pair of electrostatic separators for P2, P3, P4, P6, P7, P8 H.P. Geng

18. CEPC local double ring scheme has been Proposed at IHEP and CERN independently ： 1 ） J. Gao in June 2013 (IHEP-AC-LC Note 2013-012) 2 ） M. Moratzinos and F. Zimmermann ， IPAC, 2015 CEPC local double two ring scheme has two fold reasons: 1)Introducing large crossing angle to explore crab-waist collision aiming to reduce beam and AC power (J. Gao) 2)Avoiding using prezel scheme to increase the flexibility and increasing Z, W pole luminosities with more bunches (M. Moratzinos and 3)F. Zimmermann)

20. No pretzel scheme Crab waist possible Cost less than whole double rings More bunches for high luminosity Z, W Reduced AC power

21. F.Su, D. Wang et al

22. Main Technical Challenges for CEPC 1.Lattice design with dynamic aperture for off-momentum up to  2% 2.Pretzel orbit (single beam pipe) 3.Local double ring scheme 4.Low energy injection (6 GeV) to the Booster (low field and DA) 5.Machine-detector interface (L* = 1.5 m) 6.650MHz CW SCRF accelerating system (high efficiency) with HOM damper for the RF cavity High average beam current: 2 x 16.6 mA High HOM loss: 2 x 2.3 kW per cavity 7. Total AC power 8. Advannced detector R&D which is very challenging

23. CEPC-SPPC Timeline (preliminary) 23CEPC-SPPC Meeting, May 17-18, 2015W. Chou R&D Engineering Design (2016-2020) Construction (2021-2027) Data taking (2028-2035) Pre-studies (2013-2015) 1 st Milestone: Pre-CDR (by the end of 2014) → R&D funding request to Chinese government in 2015 (China’s 13 th Five-Year Plan 2016-2020) CEPC R&D (2014-2030) Engineering Design (2030-2035) Construction (2035-2042) Data taking (2042-2055) SPPC 2 nd Milestone: 13th Five year Plan R&D End of 2016 CEPC CDR should be completed

24. M. Benedikt

28. International efforts  CEPC-SppC pre-CDR international review have been done in the beginning of 2015  CEPC-SppC International Advisory Committee has been established and the first meeting was held in Sept. 2015 at IHEP  Start with International working groups  Establishing CEPC international collaboration common task forces  More Synergy with LCC (ILC, CLIC)  More synergy with FCC (ee, pp) ... CEPC is a chanlleging machine in terms of design, construction and operation for the high energy comminity of the world

29. Thank you for your attention!

30. Backup slides Analytical formulation of parameter choice or designs for e+e- and Proton-Proton circular colliders (CEPC-SPPC applications) References: 1) CEPC-SppC Pre-CDR, http://cepc.ihep.ac.cn/preCDR/volume.html 2) J. Gao, "Review of some important beam physics issues in electron positron collider designs", Modern Physics Letters A Vol. 30, No. 11 (2015) 1530006 (20 pages 2) D. Wang, J, Gao, et al, "Optimization parameter design of a circular e+eHiggs factory", Chinese Physics C Vol. 37, No. 9 (2013) 097003 3)M. Xiao, J. Gao, et al, "Study on CEPC performances with different collision energies and geometric layouts",IHEP-AC-LC-Note2015-002. 4) F. Su, J. Gao, et al, "Method Study of Parameter Choice for a Circular Proton-Proton Collider", Chinese Physics C (2015)

31. Luminosity from colliding beams For equally intense Gaussian beams Expressing luminosity in terms of our usual beam parameters Geometrical factor: - crossing angle - hourglass effect Particles in a bunch Transverse beam size (RMS) Collision frequency 31 where

32. For lepton collider: For hadron collider: J. Gao, “Review of some important beam physics Issues in electron positron collider designs”, Modern Physics Letters A, Vol. 30, No. 11 (2015) 1530006 (20 pages) r e is electron radius γ is normalized energy R is the dipole bending radius N IP is number of interaction points r p is proton radius J. Gao, Nuclear Instruments and Methods in Physics Research A 533 (2004) 270–274 J. Gao, Nuclear Instruments and Methods in Physics Research A 463 (2001) 50–61 where Maximum Beam-beam tune shift analytical expressions for lepton and hadron circular colliders

33. Parameters (M. Xiao, et al) 50km CEPC design Single ring schemeDouble ring scheme ZWHZWH Beam energy E[GeV] 45.58012045.580120 Circumference C[km] 50 Number of IP N IP 222222 Bending radius ρ[km] 6.094 SR power/beam P[MW] 0.891050 SR loss/turn U 0 [GeV] 0.0620.63.010.0620.63.01 Ring’s Energy acceptance η 0.02 Magnetic rigidity Bρ[T·m] 151.8266.9400.4151.8266.9400.4 Momentum compaction factor α p [10 −5 ] 2.6131.5561.4112.6131.5561.411 Lifetime due to radiative Bhabha scattering τ L [hour] 8.262.671.198.262.671.19 Beam current I[mA] 14.2316.816.6796.884.0316.62 Bunch number N b 48 268824048 Bunch population Ne[10 11 ] 3.093.653.613.093.653.61

34. x [nm·rad] 4818.686.1248206.9 y [pm·rad] 963621.2963621.2 β x [m] 0.8 β y [mm] 1.2 σ x [µm] 196122.270196122.270 σ y [µm] 0.3390.2080.1590.3390.2080.159 Bunch length σ s [mm] 2.65 Beam-beam parameter ξ x 0.0320.0560.1120.0320.0560.112 Beam-beam parameter ξ y 0.0280.0490.0740.0280.0490.074 Hourglass factor F h 0.68 Luminosity per IP L[10 34 cm −2 s −1 ] 0.220.821.8212.54.081.82 RF voltage V rf [GV]0.1670.7783.380.1670.7783.38 RF frequency f rf [GHz] 0.65 Synchrotron tune Q s 0.0170.1270.0910.0170.1270.09 Energy spread σ δ,SR [%] 0.050.090.130.050.090.13 Average number of photons emitted per electron during the collision n γ 0.0640.1220.2110.0640.1220.211

35. Parameters ( M. Xiao et al) 100km CEPC design Single ring schemeDouble ring scheme ZWHttZWH Beam energy E[GeV] 45.58012017545.580120175 Circumference C[km] 100 Number of IP N IP 22222222 Bending radius ρ[km] 11 SR power/beam P[MW] 0.6158.3550 SR loss/turn U 0 [GeV] 0.0340.3301.6687.5460.0340.3301.6687.546 Ring’s Energy acceptance η 0.02 Magnetic rigidity Bρ[T·m] 151.8266.9400.4584151.8266.9400.4584 Momentum compaction factor α p [10 −5 ] 5.7621.2331.0090.9385.7621.2331.0090.938 Lifetime due to radiative Bhabha scattering τ L [hour] 18.555.992.661.2518.555.992.661.25 Beam current I[mA] 17.9425.1230.296.631451.5153.030.296.63 Bunch number N b 192 4815600115219248 Bunch population Ne[10 11 ] 1.72.382.872.561.72.382.872.56

36. x [nm·rad] 33186.83.533186.83.5 y [pm·rad] 642418.26.2642418.26.2 β x [m] 0.8 β y [mm] 11111111 σ x [µm] 162.412073.7652.92162.412073.7652.92 σ y [µm] 0.2530.1550.1350.0790.2530.1550.1350.079 Bunch length σ s [mm]2.552.65 2.552.65 Beam-beam parameter ξ x 0.0260.0380.080.0960.0260.0380.080.096 Beam-beam parameter ξ y 0.0210.0370.0550.080.0210.0370.0550.08 Hourglass factor F h 0.6420.632 0.6420.632 Luminosity per IP L[10 34 cm −2 s −1 ] 0.241.012.751.2819.26.152.751.28 RF voltage V rf [GV]0.410.552.0648.320.410.552.0648.32 RF frequency f rf [GHz] 0.65 Synchrotron tune Q s 0.1340.0480.0590.0810.1340.0480.0590.081 Energy spread σ δ,SR [%]0.0370.0650.0980.1420.0370.0650.0980.142 Average number of photons emitted per electron during the collision n γ 0.0430.0810.1600.2000.0430.0810.1600.200

37. ParametersHiggs Factory Beam energy E[GeV]120 Circumference C[km]5070100 Number of IP N IP 2 Bending radius ρ[km]6.0948.611 SR power/beam P[MW]50 SR loss/turn U 0 [GeV]3.012.131.67 Beam current I[mA]16.623.430.3 Bunch number N b 48114220 Bunch population N e [10 11 ]3.6132.87 Horizontal emittance x [nm·rad]6.126.366.8 Vertical emittance y [pm·rad]21.22018.2 Betatron function at IP-vertical β y [mm]1.2 1 Betatron function at IP-horizontal β x [m]0.8 Transverse beam size σ x [µm]7071.373.8 Transverse beam size σ y [µm]0.160.1550.135 Beam-beam parameter ξ x 0.1120.090.08 Beam-beam parameter ξ y 0.0740.0620.055 Bunch length σ s [mm]2.65 Hourglass factor0.68 0.63 Luminosity L[10 34 cm −2 s −1 ]1.822.152.75

39. 39 Parameter choice for SPPC (Potential) …… (F. Su et al)

40. Parameter choice for SPPC (Potential) (F. Su et al)