model-independent determination of Higgs e+e- colliders

Transcription

1 model-independent determination of Higgs e+e- colliders Junping Tian (U of Tokyo) Te 20t Regular Meeting of te New Higgs Working Group, August 18-19, Osaka University

2 outline reminder of classical approac (kappa formalism) and several related questions new approac based on effective field teory formalism answers to tose questions omework and summary 2

3 based on two recent papers on arxiv soon (submitted to PRD) arxiv: arxiv:

4 reminder: model independence in kappa framework recoil mass tecnique > inclusive σ σ > κζ > Γ(->*) WW-fusion νeνe > κw > Γ(->WW*) total widt Γ = Γ( >*)/BR(->*) or Γ = Γ( >WW*)/BR(->WW*) ten all oter couplings PoS EPS-HEP2013 (2013) 316 Nucl.Part.Pys.Proc (2016)

5 te key: inclusive σ (independent of decay modes) e + H X is it really easy? e μ + μ Yan, et al, Pys.Rev. D94 (2016) ; Tomson, Eur.Pys.J. C76 (2016) 72 bias < 0.1% in leptonic recoil mode still need effort to acieve bias in adronic recoil mode < 1% 5

6 question 1: ow can we determine λ if tere are anomalous VV, VV, couplings? e + e + e e e + e + e e BSM territory -> if we measure a cange in tis cross section, wat actually do we measure? 6

7 question 2: can we assume σ(e+e- ->) Γ(->*)? e + H e? 2 H BSM territory -> can deviations be represented by single κ? 7

8 question 3: can we determine WW precisely at s = 250 GeV? WW-fusion is smaller by x10 tan 500 GeV 8

9 quick answers measure directly anomalous VV couplings using σ, dσ/dx, in e+e- > process L = M 2 ( 1 v + a ) µ µ + b 2 µ µ + b 2 µ µ (SM-like) (CP-even) (CP-odd) Ogawa, Fujii, Tian, EPS-HEP 2017 measure anomalous VV couplings and λ simultaneously using σ, dσ/dx, in e+e- > process 9

10 determine anomalous VV couplings example: ow b/b~ canges dσ/dx e + + e f s = 250GeV 10

11 determine tensor structure of VV couplings (full simulation) L = M 2 ( 1 v + a ) µ µ + b 2 µ µ + b 2 µ µ =1TeV for GeV > κζ (a) ~ 3% >> 0.38% 11

12 VV, VV and λ in e+e- > e + e + e + e + e e e e (S) (Q) (B) (B) dσ/dm(hh) [fb] All S-term Q-term B-term SQ-term SB-term QB-term [%] δκ HHH M(HH) [GeV] δκ HHVV δκvv < 5% would be needed > callenging by sape 10 [%] 2 12

13 long answers SM Effective Field Teory ( Warsaw basis, JHEP 1010 (2010) 085) 10 operators (,W,,γ): ch, ct, c6, cww, cwb, cbb, c3w, chl, c HL, che + 4 SM parameters: g, g, v, λ + 5 operators modifying couplings to b, c, τ, μ, g + 2 parameters for ->invisible and exotic 13

14 simplifications of our analysis at tree level, and to linear order in D-6 coefficients ignore some possible D-6 corrections involving ligt leptons, e.g. 4-fermion operators avoid using observables tat involve contact interactions tat include quark currents (see more later) ignore te effects of CP-violating operators 14

15 on-sell renormalization D-6 operators modify te SM expressions for precision electroweak observables, tus sift te appropriate values for te SM couplings > g, g, v, λ free parameters D-6 operators also renormalize te kinetic terms of te SM fields > rescale te boson fields 15

16 EFT input: EWPOs (7) (δχ=δx/x) δg, δg, δv, δλ, ct 16

17 EFT input: EWPOs (7) chl+c HL, che 17

18 EFT input: TGC (3) A =1+(8c WB ) A = 6g 2 c 3W 18

19 EFT input: TGC (3) 19

20 EFT input: BR(->γγ)/BR(->*), BR(->γ)/BR(->*) (2: HL-LHC) 20

21 EFT coefficients 10: ch, ct, c6, cww, cwb, cbb, c3w, chl, c HL, che + 4: g, g, v, λ can already be determined, except c6, ch > Higgs e+e- 21

22 Higgs couplings in EFT 22

23 EFT input: σ(e+e- >), σ(e+e- > ) ch as to be determined by inclusive σ measurement c6 as to be determined by double Higgs measurement EFT input: BR( >XX) couplings to b, c, τ, μ, g Γ(->invisible), total decay widt 23

24 two more parameters: CW, C for Γ(->WW*) and Γ(->*) EFT input: (c X: contact interactions) (similar for ) 24

25 question 1: ow can we determine λ if tere are anomalous VV, VV, couplings? e + e + e e e + e + e e 25

26 answer to Q1: determine λ in EFT 26

27 answer to Q1: determine λ in EFT EPS-HEP

28 question 2: can we assume σ(e+e- ->) Γ(->*)? e + H e? 2 H 28

29 answer to Q2: σ(e+e- ->) κ 2 () Γ(->*) not any more: EFT is more general tan kappa-framework L =(1+ ) m2 v µ µ + 2v µ µ e + H e = 29

30 answer to Q3: WW is determined as precisely s = 250 GeV WW/ ratio can be determined to <0.1%: feature of a general SU(2) x U(1) gauge teory SM-like VV custodial symmetry ci ~ O( ) anomalous VV 30

31 typical precisions by EFT: combined EWPO+TGC+Higgs fit ILC H20: Ldt = 2 ab 250 GeV coupling g/g kappa-fit EFT-fit 0.38% 0.66% WW 1.9% 0.65% bb 2.0% 1.0% Γ 4.2% 2.4% (for and WW couplings: 1/2 of partial widt precision) 31

32 comments on beam polarizations not canged: important for systematics control, nature of new particle (once found), e.g. Higgsino, WIMPs new roles in EFT -> separate and γζ couplings γ H -> improve ALR in -e-e coupling e + important to constrain contact interaction e e + e 32

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35 omework from EFT (limiting factors oter tan usual Higgs observables) TGC: full simulation at 250 GeV improve γ couplings: using bot ->γ and e+e- ->γ better constrain contact interactions: improve ALR improve Γ(->ee) improve Γ(W->eν) e + e e + W e 35

36 comments on validity of our EFT analysis toug most of te coefficients are assumed to be small, it is not necessary for c6, wic modifies triple iggs coupling only, would not affect te formalism of oter part (tree level) tus it can be applied to te case were λ is significantly enanced (e.g. EWBG, CSI) in general we assume te mass scales of new particles wic contribute to te D-6 operators are eavy, but it is fine wit ligt WIMP, if it is only relevant in ->invisible decay (decoupled wit oter observable) 36

37 new application: model discrimination by EFT 37

38 typical parameters of bencmark models 38

39 new development: model discrimination by EFT ga, gb: vector of couplings in Model A, B Vij: linear dependence of coupling gi on EFT coefficient cj C: covariance matrix of EFT coeffs given te coupling deviations in two models, tis χ2 gives te most appropriate separation power, taking into account all correlations 39

40 discrimination between BSM models (ILC250 stage) once find deviation against SM > can tell wic BSM 40

41 discrimination between BSM models pin down te story after full ILC 41

42 summary advantage of e+e- (e.g. ILC): model-independent determination of all Higgs couplings (and precisely) kappa formalism turns out not general enoug to accommodate all BSM effects EFT formalism (combined EWPOs+TGCs+Higgs) is more suitable, and a realistic fit based on tis formalism is proved to work very well one important conclusion based on te EFT formalism: WW coupling can be determined precisely at s = 250 GeV witout relying on WW-fusion process > go aead ILC250 EFT formalism opens up new (better) way for BSM model discrimination (next slides, proposal to teorists) 42

43 proposals (to teorists) can you calculate (all) te EFT coefficients in your preferred BSM models? (ci/v 2 ~ g/λ 2 ) η your teory ζ L =(1+ ) m2 v µ µ + 2v µ µ exp. precision 43

44 backup 44

45 indirect model dependent probe of λhhh: s ~ 250 GeV McCulloug, if only δ is deviated > δ ~ 28% if bot δz and δ deviated > δ ~ 90% δσ could receive contributions from many oter sources can be considered as a useful consistency test of SM 45

46 new development: EFT analysis Precision of Higgs coupling and witd [%] (EFT fit) -1 ILC 250 GeV, 2000 fb ILC 500 GeV, 1000 fb GeV, 1000 fb -1-1 LHC 3000 fb -1 LHC, 3000 fb g(h) g(hww) g(hbb) g(hgg) g(h γ γ ) g(hτ τ ) g(hcc) g(htt) g(hµ µ ) Γtot (CL95%) Γ invis WW/ ratio can be determined to <0.1% 46

47 expected precisions of Higgs couplings 47

48 48