CEPC-SppC: A Great Opportunity for the US-China Collaboration Yifang Wang Institute of High Energy Physics, Beijing Washington, Feb. 12, 2016

Introduction Our planet is becoming smaller and smaller with the help of nowadays technology International collaboration is a must for everyone, but there are a lot of complications due to various reasons Scientific collaboration is generally undisputed In particular, US-China collaboration on High Energy Physics(HEP) was very successful because – Common interests as Human Beings – Easily visible – No complications due to national interests, politically sensitivity, etc.

More than 30 years collaboration Agreement on HEP signed on Jan. 31, 1979 During 29 th meeting in IHEP, Nov th meeting at BNL, Nov 5-6, st meeting in Beijing, June 10-13, 1979

BEPC/BES: Starting Point BESIII US members Univ. of Hawaii Carnegie Mellon Univ. Univ. of Minnesota Univ. of Rochester Univ. of Indiana Great results on Light Hadron, Charm and Charmonium physics

AMS at the International Space Station Permanent magnet

Daya Bay Reactor Neutrino Experiment US members(16) BNL, Caltech, LBNL, Iowa State Univ., Illinois Inst. Tech., Princeton, RPI, UC-Berkeley, UCLA, Univ. of Cincinnati, Univ. of Houston, Univ. of Wisconsin, William & Mary, Virginia Tech., Univ. of Illinois-Urbana-Champaign, Siena Sin 2 2  13 =  0.016(stat)  0.005(syst)  2 /NDF = 4.26/4, 5.2 σ for non-zero θ 13

A New Era ? Scientifically – After the Higgs, game is over ? – What is the future of our field ? ILC only ? Standard Model Is not Complete Hierarchy problem Naturalness problem Vacuum issues Evidences Beyond the Standard Model Unification at a high energy Dark matter, anti-matter, dark energy Neutrinos Understanding the Higgs Coupling properties Potential shape ? New physics ? Politically: Consequences of China’s economical growth ? More investment on Science ? More as an international partner ? Continue to “open door” ? US & China: more cooperation or confrontation ?

Our Proposal: CEPC+SppC Thanks to the low mass Higgs, we can build a Circular Higgs Factory(CEPC), followed by a proton collider(SppC) in the same tunnel BTC IP1 IP2 e+e- e+ e- Linac (240m) LTB CEPC Collider Ring(50Km ) Booster(50Km ) BTC Medium Energy Booster(4.5Km) Low Energy Booster(0.4Km) IP4 IP3 SppC Collider Ring(50Km) Proton Linac (100m) High Energy Booster(7.2Km)

Great Science Electron-positron collider(90, 250, 350 GeV) – Higgs Factory: Precision study of Higgs(m H, J PC, couplings ) Similar & complementary to ILC Looking for hints of new physics – Z & W factory: precision test of SM Deviation from SM ? Rare decays ? – Flavor factory: b, c,  and QCD studies Proton-proton collider(~100 TeV) – Directly search for new physics beyond SM – Precision test of SM e.g., h 3 & h 4 couplings Precision measurement + searches: Complementary with each other !  ~  10 better over LHC ~  10 better over LEP  ~  10 better over LHC

Why in China ？ Timing (after BEPCII) Technological feasibility (experience at BEPC/BEPCII) Economy  new funding to the community Large & young population  new blood to the community Affordable tunnel & infrastructure  still cheap in China now Money will be used by somebody  It is a pity if we miss it Too expensive ? – BEPC cost/4 y/GDP of China in 1984  – SSC cost/10y/GDP of US in 1992  – LEP cost/8y/GDP of EU in 1984  – LHC cost/10y/GDP of EU in 2004  – ILC cost/8y/GDP of Japan in 2018  – CEPC cost/6y/GDP of China in 2020  – SPPC cost/10y/GDP of China in 2036  Physics wise ， CEPC+SPPC is ideal

Timeline (dream) CPEC –Pre-study, R&D and preparation work Pre-study: –Pre-CDR for R&D funding request R&D: Engineering Design: –Construction: –Data taking: SppC –Pre-study, R&D and preparation work Pre-study: R&D: Engineering Design: –Construction: –Data taking:

Current Status Initiated a global effort for the Conceptual design Pre-CDR completed – No show-stoppers – Technical challenges identified  R&D issues – Preliminary cost estimate R&D issues identified and funding request underway – Seed money from IHEP available: 12 M RMB/3 years – MOST: ~ 100 M / 5yr, hopefully next year – NCDR: ~1 B RMB / 5 yr, maybe 2017 Working towards CDR by 2016 – A working machine on paper Site selection Internationalization & organization

March 30, 2015 Can be downloaded from pages, 480 authors 328 pages, 300 authors

International Review of Pre-CDR March 30, 2015

A Candidate Site Beijing Qinhuangdao Tianjing Beidaihe 300 km from Beijing 3 h by car 1 h by train

International Collaboration Why we need international collaboration ? – Not only because we need technical help – But also for financial & political support in China To integrate China better to the international community To modernize China’s research system(“open door”) A new scheme of international collaboration, different from ITER, ILC, CERN, … An international advisory board is formed A machine of the community, and for the community A “Center for Future HEP” is established to initiate internationalization

Summary Scientific collaboration is great for our society CEPC-SppC is an unique opportunity US-China collaboration may play a special role for CEPC, and CEPC will play a special role for the US-China cooperation. Let’s be optimistic for the promising future Even if the future new accelerator is not in China, it is still very good to the Chinese HEP & Science community. We fully support a global effort