CP Sensitive Observables in VBF Production Verena Walbrecht, Katharina Ecker, Davide Cieri, Sandra Kortner Max Planck Institute for Physics (Werner-Heisenberg-Institut) Friday 5 th October, 2018
Setup Previous Talk: CP sensitivity of ∆ φ sign in VBF ( https://indico.cern.ch/event/693955/ ) jj Integrated Luminosity: L = 150 fb − 1 (end of Run II) MC samples : Prod_v12 VBF Category: n jets ≥ 2 and m jj > 120 GeV Category VBF (MG5) m 4 ℓ ∈ [118,129] GeV 18.94 VBF-enriched 9.90 Fraction 52 % Test CP Invariance: CP-odd coupling parameter κ AZZ For comparison: very simple signal model – only VBF for signal model – no background included – no width scaling (not needed for shape only fit) – no best prediction scaling – no systematics Only shape information 10/05/2018 V. Walbrecht - CP Sensitive Observables in VBF Production 2/20
CP Sensitive Observables 3 possibilities to test CP invariance in VBF production: 1. Azimuthal angle between the tagging jets in the final state: ∆ φ sign jj Previous talk: ( https://indico.cern.ch/event/693955/ ) 2. 1st optimal observable for VBF production: OO 1 , jjH Nikita’s talk: ( https://indico.cern.ch/event/693949/ ) Antoine’s talk: ( https://indico.cern.ch/event/743162/ ) Spin-CP H → ττ : ( https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HIGG-2015-06/ ) 3. 1st optimal observable for VBF production and decay: OO 1 , jj4 ℓ Supporting Note (Appendix P) - L = 36 fb − 1 : ( https://cds.cern.ch/record/2231596/files/ATL-COM-PHYS-2016-1604.pdf ) 10/05/2018 V. Walbrecht - CP Sensitive Observables in VBF Production 3/20
sign 1. Short Reminder: ∆ φ jj Definition of ∆ φ sign ∈ [ − π, π ] : jj if y leading jet >y subleading jet : if y subleading jet >y leading jet : ∆ φ sign ∆ φ sign = φ leading jet - φ subleading jet = φ subleading jet - φ leading jet jj jj 0.3 Normalized to unit area ATLAS Work in progress → → H ZZ* 4l 0.25 κ VBF SM, =1, c =1 SM α 1 κ κ 13 TeV VBF, =1, =5, c = SM AVV α 2 ≥ 1 2, > 120 GeV κ κ N m VBF, =1, =-5, c = α Discriminates between negative and j SM AVV jj 2 0.2 positive CP-odd coupling parameters 0.15 Advantage: model independent 0.1 0.05 0 − − − 3 2 1 0 1 2 3 sign ∆ φ jj 10/05/2018 V. Walbrecht - CP Sensitive Observables in VBF Production 4/20
2. Optimal Observable for VBF Production: OO 1 , jjH Matrix element for VBF production: sum of CP-even contribution from the SM and a CP-odd contribution: v · κ AVV M Mix = M SM + ˜ where ˜ d · M CP − odd , d = tan ( α ) 4 · Λ · κ SM Squared matrix element: |M Mix | 2 = |M SM | 2 + ˜ d 2 · |M CP − odd | 2 SM M CP − odd ) + ˜ d · 2 ℜ ( M ∗ Interference term is CP-odd ⇒ can be used to measure CP invariance Parameter configuration ˜ d = 1: √ √ Λ = 1 TeV , v = 246 . 22 GeV , κ SM = 2 , κ AVV = 22 . 975 , cos ( α ) = 1 / 2 Definition of optimal observables: OO 1 , jjH = |M Mix | 2 − |M SM | 2 − |M CP − odd | 2 and OO 2 , jjH = |M CP − odd | 2 |M SM | 2 |M SM | 2 10/05/2018 V. Walbrecht - CP Sensitive Observables in VBF Production 5/20
import model HC_NLO_X0_UFO p p > j j x0 $$ w+ w- z / a @0 output standalone_cpp PROC_SA_CPP_VBF 2. Optimal Observable for VBF Production: OO 1 , jjH Matrix elements are calculated with the MadGraph5 tools Option standalone_cpp : standalone C ++ code for each subprocess Takes as input the four-momenta of the incoming and outcoming particles (5) and calculates the value of the matrix element: MG5 version of EFT samples from Prod_v12: MG5_aMC_v2_3_3: 10/05/2018 V. Walbrecht - CP Sensitive Observables in VBF Production 6/20
2. Optimal Observable for VBF Production: OO 1 , jjH 60 diagrams ⇒ sum over all possible flavour configurations ij → klH weighted by the parton distribution functions |M SM | 2 = f i ( x 1 ) f j ( x 2 ) |M SM | 2 ( ij → klH ) ∑ i , j , k , l ∑ 2 ℜ ( M ∗ SM M CP − odd ) = f i ( x 1 ) f j ( x 2 ) 2 ℜ ( M ∗ SM M CP − odd ) ( ij → klH ) i , j , k , l Reconstructed Bjorken x: M jjH M jjH x reco e y jjH x reco e − y jjH √ √ = and = 1 2 s s Same PDF which was used for EFT samples: NNPDF23_lo_as_0130_qed 10/05/2018 V. Walbrecht - CP Sensitive Observables in VBF Production 7/20
2. Optimal Observable for VBF Production OO 1 , jjH : Our distribution: Nikita’s distribution: T R U T O H 0.05 C E SM SM SM R 0.045 kAvv=5 kAvv=5 kAvv=5 0.04 kAvv=-5 kAvv=-5 kAvv=-5 0.035 0.03 ( https://indico.cern.ch/event/693949/ ) 0.025 ττ -paper: 0.02 T 0.015 R U T 0.01 H 0.005 − − − − − 10 8 6 4 2 0 2 4 6 8 10 O κ 1, Avv (H → ττ Paper) Similar distribution as shown by Nikita & in the paper 10/05/2018 V. Walbrecht - CP Sensitive Observables in VBF Production 8/20
2. Optimal Observable for VBF Production: OO 2 , jjH : OO 1 , jjH : 0.3 Normalized to unit area 1 Normalized to unit area ATLAS Work in progress ATLAS Work in progress 0.9 → → → → H ZZ* 4l κ 0.25 VBF SM, =1, c =1 H ZZ* 4l κ SM α VBF SM, =1, c =1 α SM 0.8 κ κ 1 13 TeV VBF, =1, =5, c = 1 13 TeV κ κ SM AVV α VBF, =1, =5, c = 2 α SM AVV 2 ≥ 1 κ κ N 2, m > 120 GeV VBF, =1, =-5, c = ≥ κ κ 1 α N 2, m > 120 GeV VBF, =1, =-5, c = j SM AVV 0.7 jj 2 SM AVV α j jj 2 0.2 0.6 0.15 0.5 0.4 0.1 0.3 0.2 0.05 0.1 0 0 − − − − − 10 8 6 4 2 0 2 4 6 8 10 0 2 4 6 8 10 12 14 16 18 20 OO1 OO2 jjH jjH OO 1 , jjH : Discriminates between negative and positive CP-odd coupling parameters 10/05/2018 V. Walbrecht - CP Sensitive Observables in VBF Production 9/20
3. OO for VBF Production and Decay: OO 1 , jj4 ℓ BSM coupling can enter in both the production (p) and the decay (d) vertices Matrix element for VBF production and decay: M Mix = ( g SM ·M SM , p + g CP − odd ·M CP − odd , p ) · ( g SM ·M SM , d + g CP − odd ·M CP − odd , d ) Squared matrix element: |M Mix | 2 = g 4 SM |M SM , p | 2 |M SM , d | 2 + g 4 CP − odd |M CP − odd , p | 2 |M CP − odd , d | 2 + [ + g 3 |M SM , p | 2 ℜ ( |M SM , d | ∗ |M CP − odd , d | )+ SM g CP − odd + ℜ ( |M SM , p | ∗ |M CP − odd , p | ) |M SM , d | 2 ] + CP − odd ( |M SM , p | 2 |M CP − odd , d | 2 + |M CP − odd , p | 2 |M SM , d | 2 )+ + g 2 SM g 2 [ + g 3 |M CP − odd , p | 2 ℜ ( |M SM , d | ∗ |M CP − odd , d | )+ CP − odd g SM + ℜ ( |M SM , p | ∗ |M BSM , p | ) |M SM , d | 2 ] (1) . 10/05/2018 V. Walbrecht - CP Sensitive Observables in VBF Production 10/20
3. OO for VBF Production and Decay: OO 1 , jj4 ℓ Parameter configuration g SM = g CP − odd = 1: √ √ κ SM = κ AVV = 2 , cos ( α ) = 1 / 2 Assumption: |M SM , p | 2 = |M SM , d | 2 |M CP − odd , p | 2 = |M CP − odd , d | 2 and Definition of optimal observables: OO 1 , jj4 ℓ = |M Mix | 2 − |M SM | 2 − |M CP − odd | 2 − 2 · |M SM | · |M CP − odd | |M SM | 2 and OO 2 , jj4 ℓ = |M CP − odd | 2 |M SM | 2 10/05/2018 V. Walbrecht - CP Sensitive Observables in VBF Production 11/20
import model HC_NLO_X0_UFO p p > j j x0 $$ w+ w- z / a @0, x0 > z > l+ l- l+ l- standalone_cpp PROC_SA_CPP_VBF_H4l 3. OO for VBF Production and Decay: OO 1 , jj4 ℓ Matrix elements are also calculated with MadGraph5: 75 diagrams (now: 8 four-momenta as inputs) ⇒ sum over all possible flavour configurations (same as for OO 1 , jjH ) Same PDF which was used for EFT samples: NNPDF23_lo_as_0130_qed 10/05/2018 V. Walbrecht - CP Sensitive Observables in VBF Production 12/20
3. OO for VBF Production and Decay OO 1 , jj4 ℓ : Distribution from supporting note: Our distribution: 0.4 SM SM SM 0.35 kAvv=5 kAvv=5 kAvv=5 0.3 kAvv=-5 kAvv=-5 kAvv=-5 0.25 0.2 0.15 0.1 0.05 0 − − 4 2 0 2 4 6 8 10 12 O κ 1, Avv (Couplings and EFT supporting Note) Similar distribution as shown in the supporting note 10/05/2018 V. Walbrecht - CP Sensitive Observables in VBF Production 13/20
3. Optimal Observable for VBF Production and Decay: OO 2 , jj4 ℓ : OO 1 , jj4 ℓ : 0.35 Normalized to unit area Normalized to unit area ATLAS Work in progress 1.4 ATLAS Work in progress 0.3 → → → → H ZZ* 4l κ VBF SM, =1, c =1 H ZZ* 4l κ SM α VBF SM, =1, c =1 α SM 1.2 κ κ 1 13 TeV VBF, =1, =5, c = 1 13 TeV κ κ SM AVV α VBF, =1, =5, c = 2 α SM AVV 2 1 0.25 ≥ κ κ N 2, m > 120 GeV VBF, =1, =-5, c = ≥ κ κ 1 N 2, m > 120 GeV VBF, =1, =-5, c = j SM AVV α jj 2 SM AVV α j jj 2 1 0.2 0.8 0.15 0.6 0.1 0.4 0.05 0.2 0 0 − − − − − 1 0.8 0.6 0.4 0.2 0 0.2 0.4 0.6 0.8 1 0 0.0002 0.0004 0.0006 0.0008 0.001 0.0012 0.0014 0.0016 0.0018 0.002 OO1 OO2 jj4l jj4l OO 1 , jj4 ℓ : Discrimination between negative and positive CP-odd coupling parameters 10/05/2018 V. Walbrecht - CP Sensitive Observables in VBF Production 14/20
FIT comparison of ... sign 1. ... shape only: ∆ φ jj 2. ... shape only: OO 1 , jjH 3. ... shape only: OO 1 , jj4 ℓ 4. ... rate at a Luminosity of 150 fb − 1 10/05/2018 V. Walbrecht - CP Sensitive Observables in VBF Production 15/20
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