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κ coupling modifiers (update in CERN Report 4 in 2016)


This is the update of κ coupling modifiers (see CERN Report 3, Section 10.2) for Higgs-boson production and decay. The details will be described in CERN Report 4 in WG2 section.

Calculation Instructions

  1. Use the same SM input parameters for Higgs XS&BR calculations for CERN Report 4
  2. Update for Ecm=[7,8,13,14]TeV and for MH=[124.5,125.0,125.09,125.5]GeV
  3. Inclusive cross section
  4. Purely N3LO/NNLO/NLO QCD and no NLO EW correction
    • In LO κ-framework we assume that QCD corrections factorize for κ’s (but not for EW corrections).
  5. Cross section or partial decay width in significant digits.
  6. Also provide uncertainties in sigma and coefficients in kappa for THU and PU if possible.
    • Certain THU and PU should cancel out for coefficients in kappa (ex. αs etc.) but not for quark-mass.
  7. Provide information if public tool is available so that EXP can calculate themselves with experimental cuts later on.

gluon-gluon Fusion Process

  • Cross sections are calculated in N3LO QCD by Zürich group (Note by Zürich group).
  • QCD scales: μ=μFR=Mh/2.
  • PDF set: PDF4LHC15_nnlo_100

  • Numbers in bottom-quark related cross sections and corresponding κ coupling modifiers have changed with respect to CERN Report 3 (see Eq. (111) and Table 38).
  • For Mh=125 GeV at √s=8 TeV,
    • CERN Report 3: κg2 = 1.058κt2 + 0.007κb2 - 0.065κtκb
    • CERN Report 4: κg2 = 1.042κt2 + 0.002κb2 - 0.040κtκb - 0.005κtκc + 0.0005κbκc + 0.00002κc2
  • The main origins of these differences are:
    1. Due to change in central QCD scale from Mh (CERN Report 3) to Mh/2 (CERN Report 4). This affects σtt but doesn’t affect much σtb or σbb.
    2. Due to inclusion of charm quark.
    3. Due to change in quark-mass definition from on-shell mass in CERN Report 3 (Mt=172.5 GeV, Mb=4.84131 GeV) to MSbar mass in CERN Report 4 (Mt((Mt)=162.7 GeV, Mb(Mb)=4.18 GeV and Mc(3 GeV)=0.986 GeV).
      • In the MSbar scheme the light quark masses run to a significantly lower value (at scale of μ ~ Mh/2 or Mh) than their pole masses.
      • Hence there is an effect on the top-bottom interference and the bottom-bottom part (also for charm).
  • It has been checked that HIGLU (M. Spira) and Zürich calculations agree perfectly with the same input condition in on-shell mass scheme.

  7 TeV   8 TeV   13 TeV   14 TeV
Mh [GeV] 124.50 125.00 125.09 125.50   124.50 125.00 125.09 125.50   124.50 125.00 125.09 125.50   124.50 125.00 125.09 125.50
σEW [pb] 0.84 0.83 0.83 0.83   1.06 1.06 1.06 1.05   2.40 2.39 2.39 2.39   2.70 2.69 2.69 2.69
σtt [pb] 16.86 16.71 16.69 16.57   21.41 21.23 21.20 21.06   48.35 48.00 47.94 47.65   54.39 54.00 53.93 53.61
σtb [pb] -0.67 -0.66 -0.66 -0.65   -0.83 -0.82 -0.82 -0.81   -1.76 -1.74 -1.73 -1.72   -1.95 -1.93 -1.92 -1.91
σbb [pb] 0.04 0.04 0.04 0.04   0.05 0.05 0.05 0.05   0.10 0.10 0.10 0.10   0.12 0.11 0.11 0.11
σtc [pb] -0.08 -0.08 -0.08 -0.08   -0.10 -0.10 -0.10 -0.10   -0.22 -0.22 -0.22 -0.22   -0.25 -0.24 -0.24 -0.24
σbc [pb] 0.01 0.01 0.01 0.01   0.01 0.01 0.01 0.01   0.02 0.02 0.02 0.02   0.02 0.02 0.02 0.02
σcc [pb] 0.0003 0.0003 0.0003 0.0003   0.0004 0.0004 0.0004 0.0004   0.0009 0.0009 0.0009 0.0009   0.0010 0.0010 0.0010 0.0010
σtot [pb] 17.00 16.85 16.83 16.72   21.60 21.43 21.40 21.26   48.89 48.55 48.50 48.22   55.03 54.65 54.59 54.28
σQCD [pb] 16.16 16.02 16.00 15.89   20.54 20.37 20.34 20.21   46.49 46.16 46.11 45.83   52.33 51.96 51.90 51.59
κt2 1.043 1.043 1.043 1.043   1.042 1.042 1.042 1.042   1.040 1.040 1.040 1.040   1.039 1.039 1.039 1.039
κtκb -0.041 -0.041 -0.041 -0.041   -0.040 -0.040 -0.040 -0.040   -0.038 -0.038 -0.038 -0.038   -0.037 -0.037 -0.037 -0.037
κb2 0.002 0.002 0.002 0.003   0.002 0.002 0.002 0.002   0.002 0.002 0.002 0.002   0.002 0.002 0.002 0.002
κtκc -0.005 -0.005 -0.005 -0.005   -0.005 -0.005 -0.005 -0.005   -0.005 -0.005 -0.005 -0.005   -0.005 -0.005 -0.005 -0.005
κbκc 0.0006 0.0006 0.0006 0.0006   0.0005 0.0005 0.0005 0.0005   0.0004 0.0004 0.0004 0.0004   0.0004 0.0004 0.0004 0.0004
κc2 0.00002 0.00002 0.00002 0.00002   0.00002 0.00002 0.00002 0.00002   0.00002 0.00002 0.00002 0.00002   0.00002 0.00002 0.00002 0.00002

VBF Process

  • Cross sections are calculated in NNLO QCD with VBF@NNLO program (CERN Report 4, Appendix).
  • QCD scales: μ=μFR=MW.
  • PDF set: PDF4LHC15_nnlo_100 ??

  7 TeV   8 TeV   13 TeV   14 TeV
Mh [GeV] σWW [pb] σZZ [pb] κW2 κZ2   σWW [pb] σZZ [pb] κW2 κZ2   σWW σZZ κW2 κZ2   σWW [pb] σZZ [pb] κW2 κZ2
120.0 0.993 0.349 0.740 0.260   1.278 0.452 0.739 0.261   3.001 1.091 0.733 0.267   3.392 1.238 0.733 0.267
125.0 0.946 0.333 0.740 0.260   1.220 0.432 0.738 0.262   2.882 1.049 0.733 0.267   3.260 1.191 0.732 0.268
130.0 0.902 0.318 0.740 0.260   1.166 0.413 0.738 0.262   2.770 1.009 0.733 0.267   3.135 1.146 0.732 0.268

-- ReiTanaka - 2016-06-23

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PDFpdf inclusive_higgs_n3lo_ichep.pdf r1 manage 161.9 K 2016-06-23 - 15:58 ReiTanaka ggF cross section in N3LO QCD (Zurich group)
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Topic revision: r3 - 2016-06-24 - ReiTanaka
 
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