BSM Higgs production cross sections at √s = 8 TeV (update in CERN Report4 2016)

• Cross sections reported in CERN Report 4. See here and here here for previous numbers in CERN Report 3.
• Higgs cross sections and BRs in Spread sheet are available in xlsx format
• You can find figures at our gallery here.

BSM Higgs-boson production cross section calculation

• Please check Proposal on how to provide reference "Higgs" cross sections for BSM applications
• Full mass scan should be provided for major Higgs production processes:
  1. Major process: ggF, VBF, WH (also separate W⁺H and W^-H), ZH (also gg→ZH)
  2. Associated Higgs with heavy quark: ttH, bbH
  3. Associated Higgs with single top-quark: tH (bq→tHq', bg→WtH, qq→btH)
• Higgs width should be set to zero (NWA).
• Separate electroweak correction should be provided.
• For relevant processes, and if possible, the contributions proportional to different Higgs couplings should be given separately, together with the corresponding uncertainties.
• All other external parameters should be chosen as in the corresponding best SM predictions as well as the evaluation of the uncertainties.
• SM width: At each mass point, the corresponding Higgs widths calculated in the SM with the same characteristics above should be provided.
• Examples on how to use these predictions in specific cases are provided.

Mass range and step for BSM Higgs boson:

Higgs Mass range	step size	# of points	addendum
[10,150] GeV	5 GeV	29 points
[150,500] GeV	10 GeV	35 points	+ MH=125.09 GeV
[500,3000] GeV	50 GeV	50 points

• Total 115 points for M_H=[10,3000] GeV.
• Lower mass limit might depend on stability of the code at low Bjorken-x. To be assessed.

gluon-gluon Fusion Process

• Cross sections are calculated with dFG program at NNLO+NNLL QCD (only) accuracy. Separate NLO EW correction factors 1+δ_EW are also given for M_H=[100,2500]GeV.
  • This is an interim recommendation, will be updated when new N3LO QCD numbers became available.
• Calculations are the same as CERN Report 3 (i.e. top, bottom and charm quark effects are taken into account), except it is in NWA (CPS in CERN Report 3).
• Program: dFG
• QCD scales: μ=μ_F=μ_R=M_H, uncertainty estimated in the range 1/2 < μ/M_H < 2 with 1/2 < μ_F/μ_R < 2 constraint.
  • No additional THU nor PU uncertainties assigned.
• PDF set: PDF4LHC15_nnlo_30

VBF Process

• Cross sections are calculated at (approx.) NNLO QCD accuracy.
• Calculations are the same as CERN Report 3, except it is in NWA (CPS in CERN Report 3).
• Program: NNLO QCD (VBF@NNLO)
• QCD scales: μ=μ_F=μ_R=M_W, uncertainty estimated in the range 1/2 < μ/M_W < 2 (scales have been varied independently by factor 2).
  • No additional THU nor PU uncertainties assigned.
• PDF set: PDF4LHC15_nnlo_30_pdfas

WH Process

• Cross sections are calculated at NNLO QCD accuracy.
  • Calculations are the same as CERN Report 3.
• Program: NNLO QCD (VH@NNLO)
• QCD scales: μ=μ_F=μ_R=M_VH=(p_V+p_H)² for QCD part. Uncertainty is estimated in the range 1/3 < μ/M_VH < 3 (μ_F and μ_R are varied independently).
  • No additional THU nor PU uncertainties assigned.
• PDF set: PDF4LHC15_nnlo_mc (QCD part)
• Photon-induced contribution of O(5%)
  • NOT included for total cross section (agrees with CERN Report 3 numbers within 1%).

ZH Process

• Cross sections are calculated at NNLO QCD accuracy.
  • Calculations are the same as CERN Report 3.
  • gg→ZH (box-diagram) occurs as a part of NNLO QCD correction and included in the total cross section.
• Program: NNLO QCD (VH@NNLO)
• QCD scales: μ=μ_F=μ_R=M_VH=(p_V+p_H)² for QCD part. Uncertainty is estimated in the range 1/3 < μ/M_VH < 3 (μ_F and μ_R are varied independently).
  • No additional THU nor PU uncertainties assigned.
• PDF set: PDF4LHC15_nnlo_mc (QCD part)
• Photon-induced contribution of O(1%) or below
  • NOT included for total cross section (agrees with CERN Report 3 numbers).

ttH Process

• Cross sections are calculated at NLO QCD accuracy.
  • Calculations are the same as CERN Report 3.
• Program: MadGraph5_aMC@NLO (Sherpa+OpenLoops as cross ceck)
• QCD scales: μ=μ_F=μ_R=M_top+M_H/2, uncertainty estimated in the range 1/2 < μ/(M_top+M_H/2) < 2 (with 1/2 < μ_F/μ_R < 2 constraint).
  • No additional THU nor PU uncertainties assigned.
• PDF set: PDF4LHC15_nlo_30_pdfas

bbH Process

• The cross sections are the Santander matched numbers with 5FS (NNLO) and 4FS (NLO).
• Program: SusHi for 5FS and dedicated version of MadGraph5_aMC@NLO for 4FS.
• QCD scales:
  • 5FS: μ_F=M_H/4, μ_R=M_H,
  • 4FS: μ_F=μ_R=(M_H+2M_b)/4,
  • scale with 7-point variation by a factor of 2 in both cases.
• Uncertainties
  • 5FS: Linearly added scale + (PDF⊕α_s) + M_b + μ_b (PDF and α_s uncertainties are added in quadrature).
  • 4FS: Only scale uncertainties (as they are the dominant ones) and no PDF uncertainties are included.
• PDF set
  • 5FS: Dedicated sets produced with APFEL are used which are generated from the PDF4LHC15_nnlo_100 sets taken below the M_b-threshold and evolved upwards, while generating a b-PDF set at high scale.
  • 4FS: PDF4LHC15_nlo_nf4_100

tH Process (t-ch)

• Cross sections are calculated at NLO QCD accuracy in 5FS.
• Program: MadGraph5_aMC@NLO
• QCD scales: μ=μ_F=μ_R=(M_top+M_H)/4, uncertainty estimated in the range 1/2 < μ/{(M_top+M_H)/4} < 2 (with 1/2 < μ_F/μ_R < 2 constraint).
  • Flavour scheme (FS) dependence (4FS - 5FS envelope) included in the scale uncertainty. No PU uncertainty assigned.
• PDF set:
  • PDF4LHC15_nlo_30_pdfas (5FS)
  • PDF4LHC15_nlo_nf4_100 (4FS central set), used to compute the combined scale+FS uncertainty in tH t-channel.

tH Process (s-ch)

• Cross sections are calculated at NLO QCD accuracy in 5FS.
• Program: MadGraph5_aMC@NLO
• QCD scales: μ=μ_F=μ_R=(M_top+M_H)/2, uncertainty estimated in the range 1/2 < μ/{(M_top+M_H)/2} < 2 (with 1/2 < μ_F/μ_R < 2 constraint).
  • No additional THU nor PU uncertainties assigned.
• PDF set:
  • PDF4LHC15_nlo_30_pdfas (5FS)

-- ReiTanaka - 2016-03-01