DibosonResonance14TeVMC

Introduction

This page is intended to provide information about samples for diboson resonance searches at 13 and 14 TeV. The primary signal samples are sequential Standard Model (SSM) W' and Z' bosons decaying into diboson final states including the SM Higgs boson.

SSM W'/Z' Samples

The SSM W' and Z' samples are produced using PYTHIA for the following three diboson final states;
  • W' -> WZ
  • W' -> WH
  • Z' -> ZH
The WZ samples are produced with PYTHIA8 while the WH and ZH samples are produced with PYTHIA6 (as the VH processes are not implemented yet in PYTHIA8). Foe each sample, the hadronic and leptonic decays of W/Z boson are treated separately while the Higgs boson is allowed to decay to all final states. This will allow to study different Higgs decay modes in each of the hadronic/leptonic decay channels of W and Z bosons. These samples are primarily prepared for DC14 that will start in summer 2014. The center-of-mass energy in pp collisions is set to 13 TeV for all these samples.

Common Setup

The following parameter settings are used in all the W'/Z' samples;
  • Cener-of-mass energy = 13 TeV
  • MSTW2008LO PDF
  • AU2 tune for WZ, AUET2B tune for WH/ZH samples
  • SM strength of W'/Z' coupling to fermions
  • W'WZ coupling modeled by EGM : g_W'WZ = g_WWZ(SM) * (m_W/m_W')^2
  • All e, mu and tau are included for leptonic W/Z decay
  • Higgs mass = 125 GeV
  • Higgs can decay to all SM final states

Kinematic Selection

As the mass goes higher, the off-shell production of W'/Z' becomes dominant due to a large contribution of sea-quarks in protons convoluted with the tail of a Breit-Wigner resonance shape. Since the search sensitivity comes mainly from the resonance peak region, a lower cut is applied to the mass of the (virtual) W' and Z' bosons to eliminate such off-shell contribution. The cut is chosen to be
  • >1 TeV for 3 TeV nominal resonance
  • >1.5 TeV for 4 TeV nominal resonance
  • >2 TeV for 5 TeV nominal resonance
  • >2.5 TeV for 6 TeV nominal resonance
For the WZ -> lvll channel, the cut is fixed to 1 TeV regardless of the nominal mass. The low mass tail in the lvll channel may contribute to some sensitivity gain because of a low background level compared to other channels, and therefore it would be good to use a looser requirement on that in the lvll channel.

W' -> WZ -> qqqq

ECM [TeV] W' Mass [GeV] xsec x BR [fb] Width [GeV] Validation plots
13 1000 207 35.7 W' mass, dEta(W,Z), dPhi(W,Z),
W-boson mass, W-boson pT, W-boson eta,
W-decay particle ID, dPhi(q,q) of W -> qq, pT of W-decay quark, Eta of W-decay quark,
Z-boson mass, Z-boson pT, Z-boson eta,
Z-decay particle ID, dPhi(q,q) of Z -> qq, pT of Z-decay quark, Eta of Z-decay quark
13 2000 8.87 72.3
13 3000 0.802 109
13 4000 0.0912 146
13 5000 0.0118 183
13 6000 0.00178 220

W' -> WZ -> lvqq

ECM [TeV] W' Mass [GeV] xsec x BR [fb] Width [GeV] Validation plots
13 500 1620 17.2 W' mass, dEta(W,Z), dPhi(W,Z),
W-boson mass, W-boson pT, W-boson eta,
W-decay particle ID, dPhi(l,v) of W -> lv, pT of W-decay lepton, Eta of W-decay lepton,
Z-boson mass, Z-boson pT, Z-boson eta,
Z-decay particle ID, dPhi(q,q) of Z -> qq, pT of Z-decay quark, Eta of Z-decay quark
13 1000 99.2 35.7
13 2000 4.25 72.3
13 3000 0.384 109
13 4000 0.0437 146
13 5000 0.00564 183

W' -> WZ -> qqll

ECM [TeV] W' Mass [GeV] xsec x BR [fb] Width [GeV] Validation plots
13 500 484 17.2 W' mass, dEta(W,Z), dPhi(W,Z),
W-boson mass, W-boson pT, W-boson eta,
W-decay particle ID, dPhi(q,q) of W -> qq, pT of W-decay quark, Eta of W-decay quark,
Z-boson mass, Z-boson pT, Z-boson eta,
Z-decay particle ID, dPhi(l,l) of Z -> ll, pT of Z-decay lepton, Eta of Z-decay lepton
13 1000 29.8 35.7
13 2000 1.27 72.3
13 3000 0.115 109
13 4000 0.0131 146

W' -> WZ -> lvll

ECM [TeV] W' Mass [GeV] xsec x BR [fb] Width [GeV] Validation plots
13 500 232 17.2 W' mass, dEta(W,Z), dPhi(W,Z),
W-boson mass, W-boson pT, W-boson eta,
W-decay particle ID, dPhi(l,v) of W -> lv, pT of W-decay lepton, Eta of W-decay lepton,
Z-boson mass, Z-boson pT, Z-boson eta,
Z-decay particle ID, dPhi(l,l) of Z -> ll, pT of Z-decay lepton, Eta of Z-decay lepton
13 1000 14.3 35.7
13 2000 0.610 72.3
13 3000 0.0552 109
13 4000 0.00687 146

W' -> WH -> qqX (all Higgs decays)

ECM [TeV] W' Mass [GeV] xsec x BR [fb] Width [GeV] Validation plots
13 1000 379 36.1 W' mass, dEta(W,H), dPhi(W,H),
W-boson mass, W-boson pT, W-boson eta,
W-decay particle ID, dPhi(q,q) of W -> qq, pT of W-decay quark, Eta of W-decay quark,
H-boson mass, H-boson pT, H-boson eta,
H-decay particle ID, dPhi(x,x) of H -> xx, pT of H-decay b-quark, Eta of H-decay b-quark,
pT of H-decay tau-lepton, Eta of H-decay tau-lepton
13 2000 17.4 73.2
13 3000 1.59 110
13 4000 0.182 148
13 5000 0.0236 185
13 6000 0.00359 222

W' -> WH -> lvX (all Higgs decays)

ECM [TeV] W' Mass [GeV] xsec x BR [fb] Width [GeV] Validation plots
13 500 2280 17.4 W' mass, dEta(W,H), dPhi(W,H),
W-boson mass, W-boson pT, W-boson eta,
W-decay particle ID, dPhi(l,v) of W -> lv, pT of W-decay lepton, Eta of W-decay lepton,
H-boson mass, H-boson pT, H-boson eta,
H-decay particle ID, dPhi(x,x) of H -> xx, pT of H-decay b-quark, Eta of H-decay b-quark,
pT of H-decay tau-lepton, Eta of H-decay tau-lepton
13 1000 165 36.1
13 2000 7.59 73.2
13 3000 0.692 110
13 4000 0.0795 148
13 5000 0.0103 185

Z' -> ZH -> llX (all Higgs decays)

ECM [TeV] Z' Mass [GeV] xsec x BR [fb] Width [GeV] Validation plots
13 500 917 15.2 Z' mass, dEta(Z,H), dPhi(Z,H),
Z-boson mass, Z-boson pT, Z-boson eta,
Z-decay particle ID, dPhi(l,l) of Z -> ll, pT of Z-decay lepton, Eta of Z-decay lepton,
H-boson mass, H-boson pT, H-boson eta,
H-decay particle ID, dPhi(x,x) of H -> xx, pT of H-decay b-quark, Eta of H-decay b-quark,
pT of H-decay tau-lepton, Eta of H-decay tau-lepton
13 1000 61.0 32.0
13 2000 2.61 65.3
13 3000 0.236 98.5
13 4000 0.0280 132


Major updates:
-- KojiTerashi - 02 Nov 2013
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Topic revision: r5 - 2013-11-03 - unknown
 
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