CEPC Theory Discussion

Transcription

1 CEPC Theory Discussion S. Su Shufang Su U. of Arizona CEPC Workshop April 9, IHEP

2 Outline - Organization Physics - What has been done at precdr? - What s next? S. Su 2

3 - Organization S. Su 3

4 Funded Proposals - Theory Committee Jianping Ma, Tao Han, Hongjian He, Xiaogang Wen, Shan Jin 2016 funded proposals Qinghong Cao: Near degenerate dark matter CEPC, double parton SPPC Jing Shu: Precision measurements and effective operators, TGC Qishu Yan: BSM phenomenology and Monte Carlo tools Pengfei Yin: Dark matter CEPC Call for proposal (2016) in Sep S. Su 4

5 CDR Theory Effort - Liantao Wang working groups? timeline/plan?... S. Su 5

6 - Physics opportunity at CEPC Higgs/Z/W/t factory GeV precision test (Z, W, H,t) exotic decay of H: dark matter, etc. rare decay direct new physics search:ecm/2 S. Su 6

7 - Physics opportunity at CEPC Higgs/Z/W/t factory GeV precision test (Z, W, H,t) exotic decay of H: dark matter, etc. rare decay direct new physics search:ecm/2 S. Su 6

8 e+e- Machine: Lum vs. Ecm CepC (2 IPs) Circular Linear Modified from original version: Modified F. Gianotti, Higgs Hunting 2014 S. Su 7

9 e+e- Machine: Lum vs. Ecm CepC (2 IPs) Circular F. Gianotti, Higgs Hunting 2014 Modified from original version: Modified Ecm running time statistics (FCC-ee) b,c,τ Linear b,c,τ 90 GeV 1-2 yrs Z (Tera Z) 160 GeV 1-2 yrs WW(Oku W) 240 GeV 4-5 yrs 2x10 6 ZH (Mega H) 350 GeV 4-5 yrs 10 6 tt (Mega top) S. Su 7

10 PreCDR Theory Effort - 2 Higgs physics at CEPC Introduction Detector Performance Detector Simulation and Software Chain Detector Performance at the Object Level The Higgs Boson Mass, Cross Sections, and Branching Ratios Production Cross Sections of Signal and Background Processes Recoil Mass Distributions of e + e! ZH Events The e + e! ZH Production Cross Section and the Higgs Boson Mass The Production Rates of Individual Higgs Boson Decay Modes Measurements of the Higgs Branching Ratios Measurement of Higgs Width Summary of Higgs Measurements Higgs Analysis and Simulation Studies at CEPC: The Next Step Coupling Extractions and Combinations Coupling Fits The Higgs Self Coupling Implications 78 3 Electroweak Precision Physics at CEPC W, Z measurements at the CEPC Z pole measurements W mass measurement CEPC Electroweak Oblique Parameter Fit The Precision Challenge for Theorists A General To Do List for a Successful Electroweak Program Implications for New Physics Natural Supersymmetry and EWPT Composite Higgs scenarios Fermionic Higgs Portal Flavor Physics at CEPC Introduction Beauty and Charm transitions Very rare decays CPV in decays and production Charged Lepton Flavor Violation Summary 125 S. Su 8

11 - Electroweak Precision Measurements S. Su 9

12 Z Factory Tera Z, clean environment, Ecm knows < 1 MeV, possible longitudinal polarization Z lineshape: high precision MZ and ΓZ Z partial width: Nν to with Zɣ, sterile neutrino, rare decay Long. polarized beam 10 5 more statistics than LEP reduction of statistical uncertainty of a factor of 300 exp systematic uncertainty Uncertainty in theoretical interpretation ALR and sin 2 θw S. Su 10

13 EW Precision at Z pole Baseline: 100 fb -1 on Z-pole, 60 fb -1 around Z-pole scan Precision Electroweak Measurements at the CEPC Relative Error Current accuracy CEPC: baseline and improvements Systematics dominate Potential improvements - energy calibration - more statistics 10-7 M Z Z M W R b R l A b FB sin 2 W N Zhijun Liang, xxx S. Su 11

14 EW Precision - Present data CEPC fit s (MZ 2) ± [23] ± [24] (5) had (M Z 2) (276.5 ± 0.8) 10 4 [25] ± [26] m Z [GeV] ± [27] ± m t [GeV] (pole) ± 0.76 exp [28] ±0.5 th [26] ±0.2 exp ±0.5 th [29, 30] m h [GeV] ± 0.24 [26] < ±0.1 [26] m W [GeV] ± exp [23]±0.004 th [31] (±3 exp ± 1 th ) 10 3 [31] sin 2 è (23153 ± 16) 10 5 [27] (±2.3 exp ± 1.5 th ) 10 5 [32] Z [GeV] ± [27] (±5 exp ± 0.8 th ) 10 4 [33] R b b / had ± [27] ± R` had / ` ± [27] ±0.007 Electroweak Fit: S and T Oblique Parameters 0.2 Current (95%) Current (68%) CEPC (95%) 0.1 CEPC (68%) Reece, Fan, Wang (2014) T S. Su S 12

15 EW Precision: Improved CEPC m t [GeV] m W [GeV] sin 2 è Z [GeV] - Improved Error ±0.03 exp ± 0.1 th (±2 exp ± 1 th ) 10 3 (±2.3 exp ± 1.5 th ) 10 5 (±1 exp ± 0.8 th ) Current H1sL CEPC H1sL CEPC Improved H1sL 0.04 Electroweak Fit: S and T Oblique Parameters CEPC baseline: current theory H1sL CEPC baseline H1sL Improved G Z, sin 2 q: current theory H1sL Improved G Z, sin 2 q H1sL T 0.00 T S Challenge (opportunities) for theorists T S S. Su loop EW corrections one order of magnitude better than current S 0.04 CEPC optimistic Hpurple, solidl Improved m t, G Z, sin 2 q Hblue, solidl Reece, Fan, Wang (2014) T U = 0 68 % C.L S

16 EW Precision: Improved - If only improve one input at a time T S = 0 m W HsolidL sin 2 q eff HDashedL G z HDottedL m t HDot-DashedL S T = 0 m W HsolidL sin 2 q eff HDashedL G z HDottedL m t HDot-DashedL d d d now d now Reece, Fan, Wang (2014) S. Su 14

17 - Higgs Precision Deviation of SM Higgs couplings New coupling structures, beyond the SM Higgs couples to new particles S. Su 15

18 assuming the initial electron (positron) beam polarization to The ILC operation will start with the e+ e collision ener Higgs e+e- hz production), where the Higgsstrahlung process is domin processes are small, as shown in Fig. 1.4 (Left). As the ce 250 e + CEPC Preliminary 200 H Z W Total HIGGS PHYSICS AT CEPC 56 W e σ(fb) 150 Z e HZ e+ 100 e+ H W WW H e 400 e e Feynman diagrams of the e+ e! ZH, e+ e! H and e+ e! e+ e H processes. σ (e+e H + X) BR(H YY ) CEPC Preliminary Y=b,c,g,W,Z,γ,τ,µ Total σ(fb) 150 Determine all Higgs couplings (model-independent) HZ 100 Infer Higgs total decay width 50 probe invisible Higgs WW H decay H Z e e+e- f f H [GeV] Figure 2.5 Z W Z 350 e+ H HZ( νν) e e+ e Figure 1.3. Two important Higgs boson production processes at the IL W-boson fusion process (Middle) and the top-quark association (Right) Z 50 S. Su e+ HZ( νν)

19 72 72 HIGGS PHYSICS AT CEPC HIGGS PHYSICS AT CEPC Higgs Precision Table 2.9 Estimated precisions of Higgs boson property measurements at the CEPC. All the numbers refer to relative precision except for MH and BR(H! inv) for which MH and 95% CL upper limit are quoted Tablerespectively. 2.9 Estimated precisions of Higgs boson property measurements at the CEPC. All the numbers refer - to relative precision except for MH and BR(H! inv) for which MH (ZH) H respectively. 5.9 MeV 2.8% 0.51% MH Decay mode 5.9 MeV H! bb H! cc Decay mode H! gg H! bb H! H! cc H! WW H! H gg! ZZ H 2.8% (ZH) (ZH) BR 0.51% MH and 95% CL upper limit are quoted ( H) BR(H! bb) 2.8% ( H) BR(H! bb) BR 2.8% 0.28% 0.57% 2.2% 2.3% 1.6% 1.7% 1.2% 1.3% (ZH) BR 0.28% 2.2% 1.5% 1.6% 4.3% H! H! H! HW!W µµ 1.2% 9.0% H! BR 0.57% 2.3% 1.6% 1.7% 4.3% 1.3% 9.0% 1.5% 17% 1.6% 17% H ZZ! inv H! 4.3% 0.28% 4.3% 9.0% 9.0% H! µµ 17% 17% H! inv 0.28% of three basic pillars: the detector geometry design and Geant 4 Full simulation, the reconstruction al1956 gorithm development/optimization and the physics analysis. We will briefly present the status of these 1957 S. Sustudies and their perspective at CDR phase For the Geant4 Full simulation, we established a conceptual detector design (cepc-v1). Iterating with 1959 sub-detector design, we should converge to 1-2 benchmark detector design at the CDR studies. The 1955

20 Higgs Coupling Fit NEW COLLIDERS FOR A NEW FR - 1 Precision of Higgs coupling measurement (Model-IndependentFit) ILC GeV at fb -1 wi/wo HL-LHC 5 Precision of Higgs coupling measurement (Contrained Fit) 1 LHC 300/3000 fb -1 CEPC 250 GeV at 5 ab-1 wi/wo HL-LHC κb κc κg κw κτ κz κγ κμ Br(inv) κγ Figure 2.19 Top: Comparison between LHC, HL-LHC and several benchmark luminosities LHC of the CEPC The 10 parameter fit result18and comparison with the ILC. The CEPC at 250 GeV withhl-lhc 5 ab-1 1 integrated l CEPC: 1ab -1 and the ILC GeV at fb 1 are shown. The CEPC and ILC result3ab without combina 16 5ab-1 HL-LHC input as shown in dashed edges b c g W Z Precision (%) Relative Error CEPC 250 GeV at 5 ab-1 wi/wo HL-LHC Relative Error NEW COLLIDERS FOR A NEW FRONTIER 12 The sensitivity of measuring Zh and Z at CEPC have been analyzed in the previous sect 10 result from such a constraint on the SM hhh is summarized in Fig Implications S. Su In this section, we briefly discuss the most important physics implications of the Higgs prope surements at the CEPC.0 These topics have already been κmentioned in our overview section. κz κw κγ κg κb κτ κµ BRinv Γh c 18 pitulate them here briefly so that readers only reading this section may have a self-contained ac the important theoretical implications Higgs couplings measurements at the CEPC. Figure 1.2 Top: The 7 parameter fit, and comparison with the HL-LHC, discussed in detail i Many theories for physics beyond the Standard Model (BSM) have been proposed over the

21 Implications of Higgs - and EW Precision EW baryogenesis, Higgs potential effective operators: wi/wo breaking of SM symmetry naturalness, fine tuning - SUSY, fold SUSY,... - composite Higgs Higgs portal, UV completion... S. Su 19

22 - Flavor Physics (from tera Z) CP violation in b, c, tau decay rare decay of b, c, tau tau EDM charged lepton flavor violation S. Su 20

23 - To-do list S. Su 21

24 To-do list - Higgs precision - more realistic simulations for various channels - new channels, kinematic distributions - Higgs oblique parameters - SM loop corrections? sensitivity to top Yukawa? - effective operator approach - sensitivity to various BSM scenarios - fully correlated analysis of Higgs precision (like EW precision fit of Z-pole) - cosmo connection - naturalness, fine tuning -... S. Su 22

25 To-do list - EW precision measurements - more realistic simulations for mz, ΓZ, mw, sin 2 θw sensitivity - mw, ΓW from WW threshold with high statistics but w/o polarization? - higher order corrections, reduce theory error. - 4-fermion contact interactions - sensitivity to various BSM scenarios - balancing between Higgs and Z factory running time - complementarity of Higgs and EW precision for BSM implication - do we need teraz or more? -... S. Su 23

26 To-do list - direct BSM searches, LHC blind spots potential of flavor physics QCD related issues: heavy quarkonia... ttbar threshold? Detector and accelerator requirements energy calibration, luminosity, polarization,... precision of energy, momentum, angular measurements tau tag and polarization jet clustering/identification... S. Su 24