Tau Channel

LRSM에서 tau lepton을 포함하는 채널 분석을 다룹니다.

분석 개요

Heavy neutrino가 tau lepton과 함께 생성되는 과정을 연구합니다.

  • W_R → τN decay mode 분석
  • Tau identification과 reconstruction
  • Hadronic vs leptonic tau decay 구분

주요 특징

Signal Process

  • pp → W_R → τ + N_R 생성 과정
  • N_R → l + W_R^* → l + jj 붕괴
  • Final state: τ + l + jj

Tau Decay Modes

  • Hadronic tau: τ → hadrons + ν_τ (~65%)
  • Leptonic tau: τ → l + ν_l + ν_τ (~35%)
  • Mixed channels: τ_h + μ, τ_h + e

분석 전략

Tau Identification

  • Hadron-Plus-Strips (HPS): CMS tau algorithm
  • Decay mode finding: 1-prong, 3-prong 구분
  • Isolation requirements: ΔR < 0.5 cone
  • Anti-electron/muon: Fake tau rejection

Event Selection

  • At least one identified tau (p_T > 20 GeV)
  • One additional isolated lepton
  • Two or more jets from W_R decay
  • Missing transverse energy from neutrinos

배경 사건

Main Backgrounds

  • Z → ττ: Irreducible background
  • W + jets: Jet → τ fake rate
  • QCD multijet: Jet → lepton fake
  • Diboson: WW, WZ, ZZ production

Background Estimation

  • Fake factor method: Data-driven τ fake estimation
  • MC-based: Z → ττ normalization
  • ABCD method: QCD background estimation

체계적 불확실성

  • Tau energy scale (3-5%)
  • Tau identification efficiency (5-8%)
  • Jet energy scale and resolution
  • Luminosity and cross-section uncertainties