Overview of the CEPC Project

Transcription

1 Overview of the CEPC Project Hongbo Zhu (IHEP, Beijing) on behalf of the CEPC-SppC Study Group 17th Lomonosov Conference on Elementary Particle Physics, Moscow State University, Moscow, August, 2015

2 Outline Introduction Progress and status Summary and outlook FCC (80 km) CEPC-SppC (50 km) (HL-)LHC (27 km) ILC (31 km)/clic (48 km) 2

3 Introduction Where the story began presented by Prof. Qing Qin at the Accelerators for a Higgs Factory: Linear vs. Circular (HF2012) Prof. Qing Qin The Chinese HEP community has been seeking/debating on future collider experiment(s) after BEPCII/BESIII (operational till around 2020). The Higgs discovery in 2012 triggered fruitful thoughts on Higgs Factories around the world 3

4 CEPC-SppC Phase I: Circular Electron-Positron Collider (CEPC) Higgs Factory, center-of-mass energy ~240 GeV, peak luminosity ~ cm -2 s -1, 2 interaction points, ~1 M clean ZH events over 10 years precision measurements of the Higgs boson Operation at Z-pole/WW threshold EW precision measurements Phase II: Super Proton-Proton Collider (SppC) Discovery machine, center-of-mass energy TeV, peak luminosity ~ cm -2 s -1, 2 interaction points energy frontier for New Physics Other possible collisions: ep, ea, pa and AA LEP-LHC Style 4

5 CEPC Baseline Design e+ IP1 e- Booster energy ramp up GeV LTB BTC e+ e- Linac Linac 6-10 GeV BTC CEPC Booster Collision Ring s ~240 GeV IP3 CEPC Collider Ring Baseline design: Linac Booster Collision Ring Circumference ~ 54 km longer tunnel to be evaluated, not to limit the physics potential of the succeeding proton machine Single-ring utilising the pretzel scheme technically challenging, double-ring or partial double-ring also under consideration 5

6 SppC Design Considerations Reachable center-of-mass energy mostly constrained by the tunnel circumference and the high-field superconducting dipole magnets 50 km: 50 km: Bmax = 12 T, E = 50 TeV Bmax = 20 T, E = 70 TeV 70 km: Bmax = 20 T, E = 90 TeV Peak luminosity of ~ cm -2 s -1 sufficient or over-claimed for new physics search? more inputs from the physics community, arxiv:

7 High Field Superconducting Magnets Nb 3 Sn + HTS Requiring continuous R&D for over 20 years Develop 12 T Nb 3 Sn double-aperture dipole magnet Conduct basic technology research on HTS materials and wires and prototype an inserted coil of 2 3 T Develop 15 T Nb 3 Sn double-aperture dipole/quadruple magnets Conduct basic technology research on HTS materials and wires and prototype an inserted coil of 4 5 T Develop Nb 3 Sn (15 T) + HTS (5 T) or HTS (20 T) dipole magnet Knowledge and experience transfer to industry, enabling mass production 7

8 CEPC Detector Performance requirements similar to the ILC detectors, i.e. ILD and SiD Momentum resolution: Impact parameter resolution: Jet energy resolution: 1/p < GeV 1 r =5 10/(p sin 3 2 ) µm Feasibility studies based on the ILD-like detector but with additional considerations: Shorter focal length (L*) space constraints on the tracker (Si/TPC) No power-pulsing challenges on low power electronics and cooling Limited c.m. energy (up to 250 GeV) calorimeters of reduced size Possibly lower radiation background vertex detector closer to IP E/E 4% 8

9 Detector R&D Considerations Pioneered R&D efforts for the ILC detectors potential knowledge transfer Identified critical R&D items for each sub-detectors in the pre-cdr, in particular additional technological challenges to the CEPC detector Low power consumption electronics and/or more aggressive cooling without introducing too much extra material Re-design of the interaction region and optimisation of the general detector layout Operation at the Z-pole imposing additional challenges (much higher event rate), which might affect the detector technology choice Detector R&D started with funding support from IHEP 9

10 Physics Precision measurements of the Higgs properties and EW parameters Higgs mass, cross-section, branching rations, couplings, etc. p s = 250 GeV Cross-section (fb) Events ( L = 5 fb -1 ) e + e - ZH e + e - νν H e + e - e + e - H Complimentary to the physics potential of the SppC (discovery machine) e.g. deviation(s) to indicate New Physics 10

11 Cross-section Measurement Recoil mass method: to reconstruct the Z decay without touching the Higgs model independent Inclusive ZH cross section measurements: 0.51% (combined) 0.9% 2.1% 0.65% 11

12 Different Channels 12

13 Higgs Couplings Higgs couplings to fermions and gauge bosons predicted by the Standard Model (SM): g(hff;sm) and g(hv V ;SM); deviations from the SM couplings parameterised as: apple f = g(hff) g(hff;sm), apple V = g(hv V ) g(hv V ;SM) Relative Error Model-dependent fit: Precision of Higgs coupling measurement (Contrained Fit) LHC 300/3000 fb -1 CEPC 250 GeV at 5 ab -1 wi/wo HL-LHC Relative Error Model-independent fit: Precision of Higgs coupling measurement (Model-IndependentFit) ILC GeV at fb -1 wi/wo HL-LHC CEPC 250 GeV at 5 ab -1 wi/wo HL-LHC 10-3 κ b κ c κ g κ W κ τ κ Z κ γ 10-3 κ b κ c κ g κ W κ τ κ Z κ γ κ μ Br(inv) κ Γ 13

14 EW Precision Measurements EW precision measurements with significantly reduced uncertainties: R b,a b FB, sin eff W,m Z,m W,N 14

15 EW Oblique Parameter Fit Electroweak parameters S and T, describing the gauge boson self-energies, are sensitive to physics beyond the Standard Model Electroweak Fit: S and T Oblique Parameters 0.2 Current (95%) Current (68%) CEPC (95%) 0.1 CEPC (68%) Electroweak Fit: S and T Oblique Parameters 0.15 Current (68%) CEPC baseline (68%) 0.10 Improved Γ Z (68%) Electroweak Fit: S and T Oblique Parameters CEPC baseline (68%) Improved Γ Z (68%) Improved Γ Z, m t (68%) 0.05 T 0.0 T 0.00 T S S S 15

16 Possible Project Timeline CEPC Pre-studies ( ) R&D Engineering Design ( ) Construction ( ) Data taking ( ) 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 ) Preliminary Conceptual Design Reports reviewed by international review committees and released: Volume I: Physics and Detector Volume II: Accelerator CEPC-SPPC Preliminary Conceptual Design Report Volume I - Physics & Detector IHEP-CEPC-DR IHEP-CEPC-DR IHEP-EP IHEP-AC IHEP-TH CEPC-SPPC Preliminary Conceptual Design Report Volume II - Accelerator Available on the CEPC website: The CEPC-SPPC Study Group March 2015 The CEPC-SPPC Study Group March

17 Civil Engineering Geological survey and conceptual design efforts of civil engineering 17

18 Project Organisation Institution Board Accelerator Advisory Committee Steering Committee Physics & Detector Project Director Theory Institution Board and Steering Committee formed in the kick-off meeting in September 2013; conveners appointed for the three working groups: Accelerator, Physics & Detector and Theory International workshops and regular group meetings to coordinate efforts Workshop on Physics the CEPC (called by DOE), August, 2015 Schools and hand-on tutorial to train students important to inspire more young people to directly participate in the activities 18

19 Internationalisation The CEPC-SppC project will have to be international Center for Future High Energy Physics (CFHEP), with Prof. Nima Arkani- Hamed (IAS) as the director, was established on 17 December Inviting theorists (and accelerator experts) to the center to work closely with local members on related topics inputs to the pre-cdr A seed for an international lab, which can be potentially organised and managed by the community Which collaboration model to follow: LHC, ILC, ITER, or? Waiting for suggestions from the International Advisory Committee 1st IAC meeting September,

20 Towards CDR After the completion of the pre-cdr, the Study Group decided to start the CDR process, preliminary target date of completion: end of 2016 Particularly important to decide several key parameters of the collider Funding requests for R&D Initial IHEP investment ~10M RMB to organise team Seeking funding from Ministry of Sci. and Tech. (MOST) to kick-off R&D Seeking Chinese 13 th 5-year plan approval for R&D and validation CDR, TDR and preparation for construction Internationalisation The necessary step to bring forward the project 20

21 Summary and Outlook CEPC-SppC proposed to perform precision measurements of the recently discovered Higgs boson (Higgs Factory) and search for New Physics with unprecedented energy (Discovery Machine) Reached the first milestone (completion of pre-cdr) and continued to carry out R&D and request for funding support from the government International project You are more than welcome to join the adventure. Thank you for your attention! Courtesy SCOTT GARRETT 21

22 Extra Slides 22

23 Possible Project Timeline CEPC Pre-studies ( ) R&D Engineering Design ( ) Construction ( ) Data taking ( ) 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 ) SppC R&D ( ) Engineering Design ( ) Construction ( ) Data taking ( ) 23

24 Luminosities 24

25 Detector R&D: Vertex Pixel sensors with lower power consumption and fast readout Optional technologies: HR-CMOS, SOI, DEPFET, etc. Novel readout architecture and enhanced in-pixel and sensor level electronics functionality Mechanical design and cooling Light weight mechanical support structure and cables Vibration under forced-air cooling: impacts on position precision and consequentially the impact parameter resolution Air cooling or more aggressive CO2 cooling 25

26 Detector R&D: Si-Tracker Silicon micro-strip sensor with high spatial resolution Conventional p+-on-n sensor with small pitch size of ~50 μm fabricated with large size wafer (6 or even 8 ) Preferably to be thinned down to below 200 μm (less material) and with slim-edge (maximising sensitive area) Alternative pixelated strip sensors based on CMOS technology as being pursued by the ATLAS experiment for HL-LHC Front-end electronics Fabricated with 90/65 nm CMOS technology Fast electronics with low noise and low power consumption 26

27 Detector R&D: TPC Techniques and design to fully suppress the ion back flow Understand the impacts of magnetic/electric field distortion on readout modules and track reconstruction, and figure out possible solution Readout options (GEM or Micromegas) and front-end electronics (ASICs fabricated with 65 nm CMOS technology) Efficient cooling techniques: two-phase CO2 cooling or more efficient microchannel CO2 cooling Alignment and calibration system 27

28 Detector R&D: DHCAL Detector optimisation including pad size, number of detector layers, gas recirculation system, HV distribution system Readout electronics (PCB, low power ASIC FEE) Effective cooling together with power saving strategy Calibration Energy, position and density calibration Detailed shower measurement gives the possibility to use track segments (from data itself) to calibrate calorimeter Mechanics: self-support and compact model 28

29 Higgs Coupling Fit Deviation from the Standard Model parameterised as: apple f = Coupling fits with different assumptions 10 model-independent parameters: g(hff) g(hff;sm), apple V = g(hv V ) g(hv V ;SM) 9-parameter fit (assuming lepton universality): 7-parameter fit (assuming the absence of invisible and exotic decays): 29

30 Precision on Higgs Couplings 30