Charged Hadrons IP resolution in -decays and reconstruction of CP- - PowerPoint PPT Presentation

Charged Hadrons IP resolution in τ -decays and reconstruction of CP- mixing angle in H→ττ A. Raspereza, A. Tumasyan

Outline • PV resolution in ggF / VBF H→ττ processes • Charged hadron IP resolution in τ ± → π ± + ν and τ ± → π ± + π 0 + ν • CP-mixing angle reconstruction in ggF/VBF H→ττ

General Information Datasets Fall17 MC /GluGluHToTauTau_M125_13TeV_powheg_pythia8/RunIIFall17MiniAOD- 94X_mc2017_realistic_v10-v1/MINIAODSIM /VBFHToTauTau_M125_13TeV_powheg_pythia8/RunIIFall17MiniAOD-94X_mc2017_realistic_v10- v1/MINIAODSIM Phase II MC samples with noPU: /GluGluHToTauTau_M125_14TeV_powheg_pythia8/PhaseIITDRFall17MiniAOD- noPU_93X_upgrade2023_realistic_v2-v1/MINIAODSIM /VBFHToTauTau_M125_14TeV_powheg_pythia8/PhaseIITDRFall17MiniAOD- noPU_93X_upgrade2023_realistic_v2-v1/MINIAODSIM Phase II MC samples PU=200 /GluGluHToTauTau_M125_14TeV_powheg_pythia8/PhaseIITDRFall17MiniAOD- PU200_93X_upgrade2023_realistic_v2-v2/MINIAODSIM /VBFHToTauTau_M125_14TeV_powheg_pythia8/PhaseIITDRFall17MiniAOD- PU200_93X_upgrade2023_realistic_v2-v2/MINIAODSIM CMSSW_9_4_0_patch1 Selected events with Pt τ > 35, η τ < 2.3, and decay mode ≤ 1 Gen-Reco τ -matching with cone 0.3

RECO PV vs GEN PV in ggF H→ττ X Y Z difference of charged hadron Vx, Vy, Vz Reco - Gen

RECO PV vs GEN PV in VBF H→ττ difference of charged hadron Vx, Vy, Vz Reco - Gen

Impact Parameter of charged hadron Charged hadron Vertex Closest approach Leading (in our case the only) charged hadron momentum IP vector PV Linear extrapolation was used for IP vector determination

RECO IP vs GEN IP in ggF H→ττ difference of charged hadron IPx, IPy, IPz Reco - Gen

RECO IP vs GEN IP in VBF H→ττ difference of charged hadron IPx, IPy, IPz Reco - Gen

RECO IP vs GEN IP in ggF H→ττ wrt Gen-Vertex difference of charged hadron IPx, IPy, IPz Reco – Gen wrt Gen PV

CP-mixing angle reconstruction in H→ττ CP-mixing angle: φ * CP is 1. prong 0 τ + → π + + ν τ - → π - + ν Angle between normalized IP* ┴ of charged hadrons in π + π - - ZMF 2. prong 1 τ + → ρ + + ν → π + + π 0 + ν τ - → ρ - + ν → π - + π 0 + ν Angle between transverse components of Eur. Phys. J. C (2014) 74:3164 neutral hadrons ( π 0 ) momentums in π + π - - ZMF

CP- mixing angle reconstruction in H→ττ prong 0-0 τ + → π + + ν and τ - → π - + ν Angle between normalized IP* ┴ of charged hadrons in π + π - - ZMF arXiv:1510.03850v1 where

CP- mixing angle reconstruction in H→ττ prong 1-1 τ + → ρ + + ν → π + + π 0 + ν and τ - → ρ - + ν → π - + π 0 + ν Angle between P T of neutral hadrons ( π 0 ) in π + π - - ZMF arXiv:1510.03850v1 where where 2 categories : y τ > 0 or y τ < 0

CP-mixing angle reconstruction steps and combination • First we set 4-momentum of charged hadrons: q + and q – • Reconstruction of charged hadron IP vector for 0-prong and constructing (0, IP ) 4-vector, or using 4-momentum vector of π 0 for 1- prong. Let’s denote these vectors p + and p – • Boost to π + π * ± and 𝑞 * ± - - ZMF and normalization: 𝑟 where φ * = arcos ( 𝐪 ┴ · 𝐪 * – *+ ┴ ) • * – · ( 𝐪 * – = 𝐫 *+ ┴ × 𝐪 ┴ ) • For 1-prong y τ sign needs to be determined (for 0-prong it always + ) • If y τ < 0 then φ * = arcos ( 𝐪 ┴ · 𝐪 * – ┴ ) should be shifted by π to *+ combine with y τ > 0 category

CP-mixing angle in ggF H→ττ for various categories of y τ y τ > 0 y τ < 0 y τ > 0 and shifted y τ < 0 Fall17 samples Generator Level

CP-mixing angle with Fall17, Upgrade_noPU and Upgrade_200PU samples Gen Reco Gen Reco

CP-mixing angle: ggF vs VBF (Fall17) ggF ggF VBF VBF

What can be done to improve the results (separation power of φ * CP ) • Propagation of charged hadron track to the point of closest approach taking into account magnetic field (might be better IP resolution) • PV refitting excluding tracks from τ -decays (might be better IP resolution) Thank You