%CERTIFY%

FullRun2HiggsToLFV



Introduction

This page is devoted to the search for lepton flavor violating (LFV) Higgs decays in pp collisions with the Full Run 2 data.

Channels

We study the Higgs decaying into a tau and an electron or a muon (H->tau+e, H->tau+mu) and, depending on the decay mode of the tau, we have two different channels:

  • tau decaying leptonically (leplep)
  • tau decaying hadronically (lephad)

Data and MC samples

Derivations

We use derivations HIGG4D1 for leplep and HIGG4D2 for lephad. The JIRA ticket with the derivations request is here: https://its.cern.ch/jira/browse/ATLHLEPTON-257

Ntuples created with xTauFW

Ntuples were created using xTauFW and following the SM H->tautau approach (similar jobOptions). Some documentation on xTauFW can be found here: https://gitlab.cern.ch/ATauLeptonAnalysiS/HtautauAnalysisNotes/blob/master/README.md

LFV-specific xTauFW settings can be found here: https://gitlab.cern.ch/jiturbep/xTauFramework/tree/LFVH_Production_V03_wFix/

All data and MC ntuples can be found here: /eos/atlas/atlascerngroupdisk/phys-higgs/HSG4/LFV_Htaulep_R21/

  • V01/ minimal cuts
    • leplep: WARNING used HIGG4D2
    • lephad: tau_0_jet_bdt_score_trans > 0.005
  • V02/ only available for lephad
    • lephad: using MuonOLR (removes most of Zmumu bkg) and tau_0_jet_bdt_score_tran>0.05 (to reduce size of ntuples)
  • V03/ latest! trigger selection done in xTauFW
    • leplep: applying different lepton flavour cut
    • lephad: truth matching done in xTauFW, tau_0_jet_bdt_score_tran>0.0 in tau selection tool, events with tau jet bdt>0.005 OR tau jet rnn >0.01
Minimal cuts on samples:
  • LepHad selection
    • n_taus = 1
    • n_electrons+n_muons = 1 (loose, no isolation)
    • Muons: pt > 10 GeV, loose ID
    • Electrons: ID llh_loose_blayer, |eta| < 2.47 minus crack region, pt > 15 GeV
    • Taus: tau_0_jet_bdt_score_trans > (depends on version)
  • Leplep selection
    • n_taus = 0
    • n_electrons+n_muons = 2 (loose ID, no isolation)
    • different flavour leptons (V03)
    • Muons: pt > 10 GeV, loose ID
    • Electrons: ID llh_loose_blayer, |eta| < 2.47 minus crack region, pt > 15 GeV
    • Leading muon ID = Medium

DSIDs

We use the same samples as the SM H->tautau analysis, these: https://gitlab.cern.ch/ATauLeptonAnalysiS/HtautauAnalysisNotes/blob/master/README.md#samples

Their signal is one of our background and our signal samples are:

DSID NAME xsec (pb) k-factor gen eff (%)

VBFH*

345077 PoPy8EG_NNPDF30_VBFH125_etau_filt 0.03782 1 67.197
345078 PoPy8EG_NNPDF30_VBFH125_mutau_filt 0.03782 1 67.348

VBFH (new)

346194 PoPy8EG_NNPDF30_VBFH125_etau_filt 0.03782 1 67.197
346195 PoPy8EG_NNPDF30_VBFH125_mutau_filt 0.03782 1 67.348

ggH

345124 PoPy8EG_NNLOPS_nnlo_30_ggH125_etau_filt 0.4858 1 64.013
345125 PoPy8EG_NNLOPS_nnlo_30_ggH125_mutau_filt 0.4858 1 63.829

VH

345213 PoPy8EG_NNPDF30_AZNLO_WmH125J_MINLO_et 0.01373 0.5328 100
345214 PoPy8EG_NNPDF30_AZNLO_WpH125J_MINLO_et 0.01373 0.84 100
345215 PoPy8EG_NNPDF30_AZNLO_WmH125J_MINLO_mt 0.01373 0.5328 100
345216 PoPy8EG_NNPDF30_AZNLO_WpH125J_MINLO_mt 0.01373 0.84 100
345218 PoPy8EG_NNPDF30_AZNLO_ZH125J_MINLO_et 0.008839 1 100
345219 PoPy8EG_NNPDF30_AZNLO_ZH125J_MINLO_mt 0.008839 1 100
*These are meant to be replaced by VBFH (new)

Selection

Lephad channel

Leptons

  • Electron: MediumID, GradientIso, pt>27.3 GeV, |eta|<2.47 && !(|eta|>1.37 && |eta|<1.52)
  • Muon: MediumID, GradientIso, pt>27.3 GeV, |eta|<2.47
  • Tau: tightID, |charge|=1, n_tracks = 1 or 3, pt>25 GeV, |eta|<2.47 && !(|eta|>1.37 && |eta|<1.52)
Baseline
  • ntaus = 1
  • etau channel: n_electrons = 1 (0 muons)
  • mutau channel: n_muons = 1 (0 electrons)
  • tau and lepton have opposite charge
  • eBDT veto for etau channel:
    • tau_0_ele_bdt_score_trans>0.15 for 1 prong, tau_0_ele_bdt_score_trans>0.05 for 3 prongs
  • Sum( cos(deltaphi(lep,MET)) ) > -0.35
  • |Delta eta(lep,tau)| < 2
  • no b-jets
  • For LFV signal: abs(tau_0_truth_pdgId)==15 (true tau)
VBF region
  • Baseline &&
  • n_jets(pT>30 GeV) >1
  • leading jet pT> 40 GeV
  • dijet mass > 400 GeV
  • |dijet deta| > 3
nonVBF region
  • Baseline && fails VBF region cuts
Trigger selection (already applied in xTauFW)
  • Electron (2015):
    • lep_pt > 25 GeV AND ((HLT_e24_lhmedium_L1EM20VH==1 AND tau_1_electron_trig_HLT_e24_lhmedium_L1EM20VH==1) OR (HLT_e60_lhmedium==1 AND tau_1_electron_trig_HLT_e60_lhmedium==1) OR (HLT_e120_lhloose==1 AND tau_1_electron_trig_HLT_e120_lhloose==1))
  • Muon (2015):
    • lept_pt > 21 GeV AND ((HLT_mu20_iloose_L1MU15==1 AND tau_1_muon_trig_HLT_mu20_iloose_L1MU15==1) OR (HLT_mu50==1 AND tau_1_muon_trig_HLT_mu50==1))
  • Electron (2016,2017,2018):
    • lep_pt > 27 GeV AND ((HLT_e26_lhtight_nod0_ivarloose==1 AND tau_1_electron_trig_HLT_e26_lhtight_nod0_ivarloose==1) OR (HLT_e60_lhmedium_nod0==1 AND tau_1_electron_trig_HLT_e60_lhmedium_nod0==1) OR (HLT_e140_lhloose_nod0==1 AND tau_1_electron_trig_HLT_e140_lhloose_nod0==1))
  • Muon (2016,2017,2018):
    • lep_pt > 27.3 GeV AND ((HLT_mu26_ivarmedium==1 AND tau_1_muon_trig_HLT_mu26_ivarmedium==1) OR (HLT_mu50==1 AND tau_1_muon_trig_HLT_mu50==1))
Truth matching (already applied in xTauFW)
  • Remove events where abs(tau_0_matched_pdgId)<7 OR tau_0_matched_pdgId==21

Lephad Yields

  • Using mc16a V03 samples, new VBFH samples:

etau, nonVBF mutau, nonVBF
Sample Yields Stat. error Yields Stat. error
Data 188869 434.59 160022 400.03
LFV_ggH 1180.87 3.21 1172.89 3.18
LFV_VBFH 52.46 0.26 52.74 0.26
LFV_VH 32.81 0.29 32.69 0.29
Ztt_Jets 83198.59 259.71 95638.46 282.82
Zll_Jets 43500.33 902.27 4190.48 221.27
Top 2233.34 20.34 2144.24 19.54
Diboson 2000.79 17.14 1956.87 15.34
SMH 804.23 3.75 875.76 3.94
W_Jets 1443.23 283.11 1364.18 220.64
Fakes 62953.42 186.42 55190.45 131.6
etau, VBF mutau, VBF
Sample Yields Stat. error Yields Stat. error
Data 1594 39.92 1417 37.64
LFV_ggH 14.98 0.32 15.68 0.32
LFV_VBFH 30.24 0.2 29.54 0.19
LFV_VH 0.49 0.04 0.56 0.04
Ztt_Jets 652.42 18.38 688.22 19.59
Zll_Jets 110.34 24.59 15.21 2.57
Top 142.22 5.05 127.03 4.63
Diboson 52.38 1.52 46.81 1.45
SMH 38.79 0.5 39.83 0.5
W_Jets 10.08 7.18 17.85 7.83
Fakes 613.18 12.5 618.32 11.31
-- JuliaIturbe - 2019-02-18
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Topic revision: r7 - 2019-06-04 - JuliaIturbe
 
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