Difference: LHCHXSWGCrossSectionsCalc (1 vs. 38)

Revision 382017-01-27 - ReiTanaka

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META TOPICPARENT name="LHCHXSWG"
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  • Set ALLOWTOPICCHANGE = ReiTanaka, lhc-higgs-steering-committee
-->
Changed:
<
<

Higgs Production Cross Section and Decay Branching Ratio Calculation for RUN-2

>
>

Higgs Production Cross Section and Decay Branching Ratio Calculation for CERN Yellow Report 4

 
Changed:
<
<
Help This is the instruction fo Higgs-boson production cross section and decay branching ratio calculations for RUN-2 (to be published in CERN Report 4).
>
>
Help This is the instruction fo Higgs-boson production cross section and decay branching ratio calculations for RUN-2 (to be published in CERN Yellow Report 4).
 
  • See this link for previous instructions for 7 and 8 TeV in RUN-1.

Revision 372016-12-13 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="LHCHXSWG"
<!--
Changed:
<
<
>
>
  • Set ALLOWTOPICCHANGE = ReiTanaka, lhc-higgs-steering-committee
 
-->

Higgs Production Cross Section and Decay Branching Ratio Calculation for RUN-2

Revision 362016-02-03 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="LHCHXSWG"
<!--  
Line: 75 to 75
 
Changed:
<
<

Red led 2. BSM Higgs-boson production cross section calculation

>
>

Red led 2. BSM Higgs-boson production cross section calculation and decay width

 

Aqua led Mass scan: √s = 7 and 8 TeV (for updates) and 13 and 14 TeV

Revision 352016-02-03 - AlexandreNikitenko

Line: 1 to 1
 
META TOPICPARENT name="LHCHXSWG"
<!--  
Line: 118 to 118
 
  • As these uncertainties change smoothly, it would be enough to do the coarse scan.
    • Please carry out the interpolation with spline fit (or 3rd order polynomial fit) for other Higgs mass points.
Changed:
<
<

ii) Theory Uncertainty (THU)

  • THU should indicate both missing higher-order effects (which will not be assessed only by scale variations) as well uncertainties due to the method of calculation (e.g. threshold expansion).
>
>

ii) Theory Uncertainty (THU) (M. Spira's definition)

  • For all processes that are known up to certain QCD order exactly the scale dependence is sufficient. For any incomplete calculation as e.g. ggF or Higgs pairs there are additional missing higher-order mass effects. In addition in the context of elw. corrections the THUs will of course be estimated in a different way than just looking at the scale dependence. But this should be discussed by the corresponding subgroup contributions. In this way it makes sense to ask for additional THUs (for elw. stuff and missing mass effects).
 

iii) Parametric Uncertainty (PU)

  • PU should include the uncertainties due to quark-masses, αs, and they should be separated (to facilitate to combine results in different Higgs boson production and decay channels).

Revision 342016-01-15 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="LHCHXSWG"
<!--  
Line: 83 to 83
 
  • 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
Changed:
<
<
    1. Associated Higgs with single top-quark: tH (bq→tHq', bg→WtH, qq→btH)
>
>
    1. Associated Higgs with single top-quark: tH (bq→tHq', bg→WtH, qq→btH) (only for 13 and 14 TeV)
 
  • 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.

Revision 332015-12-03 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="LHCHXSWG"
<!--  
Line: 38 to 38
 
Changed:
<
<

Red led 1. SM Higgs-boson production cross section calculation

>
>

Red led 1. SM Higgs-boson production cross section and decay branching ratio calculation

 

Aqua led Mass scan: √s = 7 and 8 TeV (for updates) and 13 and 14 TeV

Line: 51 to 51
 
    1. Higgs pair/triple production: HH, ttHH, qqHH, tjHH, VHH, VVHH, HHH (V=W,Z)
    2. Associated Higgs with gauge boson: VVH (V=γ,W,Z)
Added:
>
>
  • Full mass scan should be provided for major Higgs decay channels.
  • Only at MH=[124.5, 125.0, 125.09, 125.5] GeV (4 points) for rare Higgs decay channels.
 

Mass range and step for SM-like Higgs boson:

Higgs Mass range step size # of points addendum

Revision 322015-11-28 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="LHCHXSWG"
<!--  
Line: 104 to 104
 
    • Highest-order EW corrections should be included and associated uncertainties should be estimated.
  • It should be discussed and agreed in each subgroup how to estimate QCD and EW uncertainties.
Changed:
<
<

QCD scale uncertainty

>
>
  • For both Higgs cross section and decay branching ratio, theory uncertainties (THU) and parametric uncertainties (PU) should be separated.
  • Following i) QCD scale Uncertainty, ii) Theory Uncertainty (THU) and iii) Parametric Uncertainty (PU) should be calculated.

i) QCD Scale Uncertainty

 
  • The factorization and the renormalization scales are process dependent and should be defined by each subgroup.
  • The scale uncertainty should also be defined by each group, (e.g.. 1/2MH < μR, μF < 2MH, do 2D scan with 1/2 < μRF < 2).
  • As these uncertainties change smoothly, it would be enough to do the coarse scan.
    • Please carry out the interpolation with spline fit (or 3rd order polynomial fit) for other Higgs mass points.
Added:
>
>

ii) Theory Uncertainty (THU)

  • THU should indicate both missing higher-order effects (which will not be assessed only by scale variations) as well uncertainties due to the method of calculation (e.g. threshold expansion).

iii) Parametric Uncertainty (PU)

  • PU should include the uncertainties due to quark-masses, αs, and they should be separated (to facilitate to combine results in different Higgs boson production and decay channels).
 

Orange led 4. PDF set and PDF+αs uncertainty calculations

Line: 147 to 156
 

Purple led 5. Numerical results

  • Results should be reported in the following format:
Changed:
<
<
    • XS ±Scale Uncertainty [%] ±PDF Uncertainty [%] ±Uncertainty due to αs [%]
    • BR ±Theory Uncertainty [%] ±Parametric Uncertainty (quark-mass) [%] ±Uncertainty due to αs [%]
>
>
    • XS ±Scale Uncertainty [%] ±THU [%] ±PU(quark-mass) [%] ±PU(αs) [%] ±PDF Uncertainty [%]
    • BR ±THU [%] ±PU(quark-mass) [%] ±PU(αs) [%]
 
  • We recommend XS and BR numbers given in 4 significant digits (ex. 12.34 pb) and uncertainties should have 1 sub-digit in % (ex. ±1.2%).
Added:
>
>
  • PU(quark-mass) [%] should be the quadratic sum of uncertainties due to top, bottom and charm quarks.
 


Revision 312015-11-27 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="LHCHXSWG"
<!--  
Line: 135 to 135
 
  • 4FS PDF set should be used for corresponding processes.

  • For LO process combined PDFLHC set does not exist (yet). Either dedicated LO PDF set or combined PDF4LHC NLO PDF set can be used.
Changed:
<
<
    • Warning: The theoretical uncertainty on LO is very large and dominant in general. If NLO PDFs are used in a LO computation, the nominal PDF uncertainty is not representative of the actual PDF uncertainty.
>
>
    • Warning: The theoretical uncertainty on LO is very large and dominant in general. If NLO PDFs are used in a LO computation, the nominal PDF uncertainty may not be representative of the actual PDF uncertainty.
 

PDF and QCD αs(MZ) uncertainties

Revision 302015-11-27 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="LHCHXSWG"
<!--  
Line: 135 to 135
 
  • 4FS PDF set should be used for corresponding processes.

  • For LO process combined PDFLHC set does not exist (yet). Either dedicated LO PDF set or combined PDF4LHC NLO PDF set can be used.
Changed:
<
<
    • Warning: The general behaviour of LO compared to NLO PDFs compensates in some manner for missing higher order corrections. However, this is not in a very universal fashion, and there is a large missing theoretical uncertainty which is associated with the PDF. Therefore the nominal NLO PDF uncertainty is no longer representative of the actual PDF uncertainty. Special caution should be taken when using combined PDF4LHC NLO PDF set.
>
>
    • Warning: The theoretical uncertainty on LO is very large and dominant in general. If NLO PDFs are used in a LO computation, the nominal PDF uncertainty is not representative of the actual PDF uncertainty.
 

PDF and QCD αs(MZ) uncertainties

Revision 292015-11-27 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="LHCHXSWG"
<!--  
Line: 123 to 123
 
  1. For BSM Higgs, PDF4LHC15_mc set can be used.
Deleted:
<
<
  • 4FS PDF set should be used for corresponding processes.
 

PDF set

Process SM Higgs BSM Higgs
Line: 134 to 132
 
Uncertainties PDF4LHC15_nlo_100_pdfas PDF4LHC15_nnlo_100_pdfas PDF4LHC15_nlo_mc_pdfas PDF4LHC15_nnlo_mc_pdfas
PDF4LHC15_nlo_30_pdfas PDF4LHC15_nnlo_30_pdfas - -
Added:
>
>
  • 4FS PDF set should be used for corresponding processes.

  • For LO process combined PDFLHC set does not exist (yet). Either dedicated LO PDF set or combined PDF4LHC NLO PDF set can be used.
    • Warning: The general behaviour of LO compared to NLO PDFs compensates in some manner for missing higher order corrections. However, this is not in a very universal fashion, and there is a large missing theoretical uncertainty which is associated with the PDF. Therefore the nominal NLO PDF uncertainty is no longer representative of the actual PDF uncertainty. Special caution should be taken when using combined PDF4LHC NLO PDF set.
 

PDF and QCD αs(MZ) uncertainties

  • QCD αs(MZ) should be set as 0.1180+-0.0015.
  • Separate PDF and αs uncertainties should be provided.

Revision 282015-11-26 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="LHCHXSWG"
<!--  
Line: 143 to 143
 

Purple led 5. Numerical results

  • Results should be reported in the following format:
Changed:
<
<
    • XS (4 significant digits) ±Scale Uncertainty [%] ±PDF Uncertainty [%] ±Uncertainty due to αs [%]
    • BR (4 significant digits) ±Theory Uncertainty [%] ±Parametric Uncertainty (quark-mass) [%] ±Uncertainty due to αs [%]
>
>
    • XS ±Scale Uncertainty [%] ±PDF Uncertainty [%] ±Uncertainty due to αs [%]
    • BR ±Theory Uncertainty [%] ±Parametric Uncertainty (quark-mass) [%] ±Uncertainty due to αs [%]
  • We recommend XS and BR numbers given in 4 significant digits (ex. 12.34 pb) and uncertainties should have 1 sub-digit in % (ex. ±1.2%).
 


Revision 272015-11-26 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="LHCHXSWG"
<!--  
Line: 46 to 46
 
    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)
Changed:
<
<
  • Only at MH=[124.5, 125.0, 125.09, 125.5] GeV (4 points) for rare Higgs production processes (σ < O(100) fb) and rare Higgs decay channels:
>
>
  • Only at MH=[124.5, 125.0, 125.09, 125.5] GeV (4 points) for rare Higgs production processes (σ < O(100) fb) and rare Higgs decay channels:
 
    1. Associated Higgs with heavy quark: ccH
    2. Higgs pair/triple production: HH, ttHH, qqHH, tjHH, VHH, VVHH, HHH (V=W,Z)
    3. Associated Higgs with gauge boson: VVH (V=γ,W,Z)
Line: 118 to 118
 
  • All these PDF sets are on Hepforge LHAPDF.

  1. For highest precision in the case of SM Higgs (ex. ggF, VBF, etc.), PDF4LHC15_100 set should be used.
Changed:
<
<
    • However in situations when computational speed is needed or a more limited number of error PDFs may be desirable, PDF4LHC15_30 set can be used.
  1. For BSM Higgs, PDF4LHC15_mc set can be used.
>
>
    • However in situations when computational speed is needed or a more limited number of error PDFs may be desirable, PDF4LHC15_30 set can be used.
    • Both PDF4LHC15_100 and PDF4LHC15_30 sets reproduce well the 900 replica (prior) PDF set for SM Higgs mass (See Figure 15 of PDF4LHC recommendations for LHC Run II).
  1. For BSM Higgs, PDF4LHC15_mc set can be used.
 
  • 4FS PDF set should be used for corresponding processes.
Line: 139 to 141
 
Added:
>
>

Purple led 5. Numerical results

  • Results should be reported in the following format:
    • XS (4 significant digits) ±Scale Uncertainty [%] ±PDF Uncertainty [%] ±Uncertainty due to αs [%]
    • BR (4 significant digits) ±Theory Uncertainty [%] ±Parametric Uncertainty (quark-mass) [%] ±Uncertainty due to αs [%]
 

-- ReiTanaka - 19-Nov-2015

Revision 262015-11-25 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="LHCHXSWG"
<!--  
Line: 46 to 46
 
    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)
Changed:
<
<
  • Only for MH=(124.5,125.0,125.5) GeV and 125.09 GeV for rare Higgs production processes (σ < O(100) fb) and rare Higgs decay channels:
>
>
  • Only at MH=[124.5, 125.0, 125.09, 125.5] GeV (4 points) for rare Higgs production processes (σ < O(100) fb) and rare Higgs decay channels:
 
    1. Associated Higgs with heavy quark: ccH
    2. Higgs pair/triple production: HH, ttHH, qqHH, tjHH, VHH, VVHH, HHH (V=W,Z)
    3. Associated Higgs with gauge boson: VVH (V=γ,W,Z)

Revision 252015-11-25 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="LHCHXSWG"
<!--  
Line: 60 to 60
 
  • Total 38 points for MH=[120,130] GeV.
  • Empirical function of cross section as a function of Higgs-boson mass should be provided.
Changed:
<
<

Aqua led Ecm scan: √s = [6,15] TeV with 1 TeV step

>
>

Aqua led Ecm scan: √s = [6,15] TeV with 0.5 TeV step (19 points)

 
  • Ecm 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)
Line: 121 to 121
 
    • However in situations when computational speed is needed or a more limited number of error PDFs may be desirable, PDF4LHC15_30 set can be used.
  1. For BSM Higgs, PDF4LHC15_mc set can be used.
Added:
>
>
  • 4FS PDF set should be used for corresponding processes.
 

PDF set

Process SM Higgs BSM Higgs

Revision 242015-11-23 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="LHCHXSWG"
<!--
Changed:
<
<
>
>
 
-->

Higgs Production Cross Section and Decay Branching Ratio Calculation for RUN-2

Line: 46 to 46
 
    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)
Changed:
<
<
  • Only for MH=125.0 and 125.09 GeV for rare Higgs production processes (σ < O(100) fb) and rare Higgs decay channels:
>
>
  • Only for MH=(124.5,125.0,125.5) GeV and 125.09 GeV for rare Higgs production processes (σ < O(100) fb) and rare Higgs decay channels:
 
    1. Associated Higgs with heavy quark: ccH
    2. Higgs pair/triple production: HH, ttHH, qqHH, tjHH, VHH, VVHH, HHH (V=W,Z)
    3. Associated Higgs with gauge boson: VVH (V=γ,W,Z)
Line: 98 to 98
 
Changed:
<
<

Green led 3. QCD scale uncertainty

>
>

Green led 3. QCD and EW corrections and uncertainties

  • Complete inclusive Higgs boson production cross sections and decay branching ratios should be estimated.
    • Highest-order QCD corrections should be included and associated uncertainties should be calculated as below.
    • Highest-order EW corrections should be included and associated uncertainties should be estimated.
  • It should be discussed and agreed in each subgroup how to estimate QCD and EW uncertainties.
 
Changed:
<
<
  • It should be discussed in each subgroup how to estimate QCD scale uncertainty.
>
>

QCD scale uncertainty

 
  • The factorization and the renormalization scales are process dependent and should be defined by each subgroup.
  • The scale uncertainty should also be defined by each group, (e.g.. 1/2MH < μR, μF < 2MH, do 2D scan with 1/2 < μRF < 2).

Revision 232015-11-20 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="LHCHXSWG"
<!--  
-->
Changed:
<
<

Higgs Cross Section Calculation for RUN-2

>
>

Higgs Production Cross Section and Decay Branching Ratio Calculation for RUN-2

  Help This is the instruction fo Higgs-boson production cross section and decay branching ratio calculations for RUN-2 (to be published in CERN Report 4).
  • See this link for previous instructions for 7 and 8 TeV in RUN-1.
Line: 16 to 16
 
<!--   * See also TWiki page. -->
Added:
>
>

Aqua led Lepton (PDG2014) &Quark Masses

e μ τ
0.510998928(11) MeV 105.6583715(35) MeV 1776.82(16) MeV
u c t
100 MeV 0.986 ± 0.026 GeV 172.5 ± 1.0 GeV
d s b
100 MeV 100 MeV 4.18 ± 0.03 GeV
  1. The top-quark mass is on-shell top-quark mass MtOS. Corresponding MS-bar mass is MtMS(Mt)=162.7±1.0 GeV.
  2. The bottom-quark mass is MS-bar bottom-quark mass MbMS(Mb). Corresponding on-shell mass is MbOS=4.92±0.13 GeV.
  3. The charm-quark mass is evaluated at Mc(3 GeV). On-shell charm-quark mass is McOS=1.51±0.13 GeV.

Green led Gauge Boson Masses and Widths (PDG2014)

W MW ΓW
  80.385(15) GeV 2.085(42) GeV
Z MZ ΓZ
  91.1876(21) GeV 2.4952(23) GeV
 

Red led 1. SM Higgs-boson production cross section calculation

Line: 25 to 45
 
  • 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
Added:
>
>
    1. Associated Higgs with single top-quark: tH (bq→tHq', bg→WtH, qq→btH)
 
  • Only for MH=125.0 and 125.09 GeV for rare Higgs production processes (σ < O(100) fb) and rare Higgs decay channels:
    1. Associated Higgs with heavy quark: ccH
Deleted:
<
<
    1. Associated Higgs with single top-quark: tH (bq→tHq', bg→WtH, qq→both)
 
    1. Higgs pair/triple production: HH, ttHH, qqHH, tjHH, VHH, VVHH, HHH (V=W,Z)
    2. Associated Higgs with gauge boson: VVH (V=γ,W,Z)

Mass range and step for SM-like Higgs boson:

Changed:
<
<
Higgs Mass range step size # of points addendum
>
>
Higgs Mass range step size # of points addendum
 
[120,124] GeV 0.5 GeV 9 points  
[124,126] GeV 0.1 GeV 20 points + MH=125.09 GeV
[126,130] GeV 0.5 GeV 8 points  
Line: 45 to 65
 
  • Ecm 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
Changed:
<
<
    1. Associated Higgs with single top-quark: tH (bq→tHq', bg→WtH, qq→both)
>
>
    1. Associated Higgs with single top-quark: tH (bq→tHq', bg→WtH, qq→btH)
 
  • Should be scanned for both MH=125.0 and 125.09 GeV.
Line: 59 to 79
 
  • 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
Changed:
<
<
    1. Associated Higgs with single top-quark: tH (bq→tHq', bg→WtH, qq→both)
>
>
    1. 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.
Line: 69 to 89
 

Mass range and step for BSM Higgs boson:

Changed:
<
<
Higgs Mass range step size # of points addendum
>
>
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  
Line: 88 to 108
 
  • Please carry out the interpolation with spline fit (or 3rd order polynomial fit) for other Higgs mass points.
Changed:
<
<

Orange led 4. PDF+αs uncertainty calculations

>
>

Orange led 4. PDF set and PDF+αs uncertainty calculations

 
Added:
>
>
  • All these PDF sets are on Hepforge LHAPDF.

  1. For highest precision in the case of SM Higgs (ex. ggF, VBF, etc.), PDF4LHC15_100 set should be used.
    • However in situations when computational speed is needed or a more limited number of error PDFs may be desirable, PDF4LHC15_30 set can be used.
  2. For BSM Higgs, PDF4LHC15_mc set can be used.
 

PDF set

Deleted:
<
<
 
Changed:
<
<

PDF and QCD αs(MZ) uncertainties

  • QCD αs(MZ) should be set as 0.1180+-0.0015.
>
>
Process SM Higgs BSM Higgs
NLO QCD NNLO QCD NLO QCD NNLO QCD
Central value PDF4LHC15_nlo_100 PDF4LHC15_nnlo_100 PDF4LHC15_nlo_mc PDF4LHC15_nnlo_mc
PDF4LHC15_nlo_30 PDF4LHC15_nnlo_30 - -
Uncertainties PDF4LHC15_nlo_100_pdfas PDF4LHC15_nnlo_100_pdfas PDF4LHC15_nlo_mc_pdfas PDF4LHC15_nnlo_mc_pdfas
PDF4LHC15_nlo_30_pdfas PDF4LHC15_nnlo_30_pdfas - -
 
Added:
>
>

PDF and QCD αs(MZ) uncertainties

  • QCD αs(MZ) should be set as 0.1180+-0.0015.
 
  • Separate PDF and αs uncertainties should be provided.
    • The total PDF+αs uncertainty is evaluated by adding the variations of PDFs and αs uncertainties in quadrature.
Changed:
<
<
>
>
 


Revision 222015-11-20 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="LHCHXSWG"
<!--  
Line: 6 to 6
 

Higgs Cross Section Calculation for RUN-2

Changed:
<
<
Help This is the instruction fo Higgs-boson production cross section and decay branching ratio calculations at centre-of-mass energy of 13 and 14 TeV. See this link for previous instructions for 7 and 8 TeV in RUN-1.
>
>
Help This is the instruction fo Higgs-boson production cross section and decay branching ratio calculations for RUN-2 (to be published in CERN Report 4).
  • See this link for previous instructions for 7 and 8 TeV in RUN-1.
 
Line: 22 to 23
 

Aqua led Mass scan: √s = 7 and 8 TeV (for updates) and 13 and 14 TeV

  • Full mass scan should be provided for major Higgs production processes:
Changed:
<
<
    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, ccH
>
>
    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
 
  • Only for MH=125.0 and 125.09 GeV for rare Higgs production processes (σ < O(100)fb) and rare Higgs decay channels:
Changed:
<
<
    1. Associated Higgs with single top-quark: tH (bq->tHq', bg->WtH, qq->both)
>
>
    1. Associated Higgs with heavy quark: ccH
    2. Associated Higgs with single top-quark: tH (bq→tHq', bg→WtH, qq→both)
 
    1. Higgs pair/triple production: HH, ttHH, qqHH, tjHH, VHH, VVHH, HHH (V=W,Z)
    2. Associated Higgs with gauge boson: VVH (V=γ,W,Z)
Line: 41 to 43
 

Aqua led Ecm scan: √s = [6,15] TeV with 1 TeV step

  • Ecm scan should be provided for major Higgs production processes:
Changed:
<
<
    1. Major process: ggF, VBF, WH (also separate W+H and W-H), ZH (also gg->ZH)
>
>
    1. Major process: ggF, VBF, WH (also separate W+H and W-H), ZH (also gg→ZH)
 
    1. Associated Higgs with heavy quark: ttH, bbH
Changed:
<
<
    1. Associated Higgs with single top-quark: tH (bq->tHq', bg->WtH, qq->both)
  • MH=125.0 GeV.
>
>
    1. Associated Higgs with single top-quark: tH (bq→tHq', bg→WtH, qq→both)
  • Should be scanned for both MH=125.0 and 125.09 GeV.
 


Line: 55 to 57
 
Changed:
<
<
    1. Major process: ggF, VBF, WH (also separate W+H and W-H), ZH (also gg->ZH)
>
>
    1. Major process: ggF, VBF, WH (also separate W+H and W-H), ZH (also gg→ZH)
 
    1. Associated Higgs with heavy quark: ttH, bbH
Changed:
<
<
    1. Associated Higgs with single top-quark: tH (bq->tHq', bg->WtH, qq->both)
>
>
    1. Associated Higgs with single top-quark: tH (bq→tHq', bg→WtH, qq→both)
 
  • 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.
Line: 72 to 74
 
[150,500] GeV 10 GeV 35 points + MH=125.09 GeV
[500,3000] GeV 50 GeV 50 points  
  • Total 115 points for MH=[10,3000] GeV.
Changed:
<
<
  • Lower mass limit might depend on stability of the code at low Bjorken x. To be assessed.
>
>
  • Lower mass limit might depend on stability of the code at low Bjorken-x. To be assessed.
 
Line: 88 to 90
 

Orange led 4. PDF+αs uncertainty calculations

Changed:
<
<
>
>
 

PDF set

Revision 212015-11-19 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="LHCHXSWG"
<!--  
-->
Changed:
<
<

Higgs Cross Section Calculation at 7, 8 and 14 TeV

>
>

Higgs Cross Section Calculation for RUN-2

 
Changed:
<
<
Help This is the instruction for Higgs cross section calculations at centre-of-mass energy of 7, 8 and 14 TeV.

Complete inclusive cross sections at LO, NLO and NNLO(+NNLL) should be calculated.

>
>
Help This is the instruction fo Higgs-boson production cross section and decay branching ratio calculations at centre-of-mass energy of 13 and 14 TeV. See this link for previous instructions for 7 and 8 TeV in RUN-1.
 
Changed:
<
<

Aqua led Centre-of-mass Energy = 7, 8 and 14 TeV

Blue led Standard Model input parameter

Gray led Higgs mass range and step:

  • MH=[80, 300]GeV for ggF, VBF, WH/ZH and ttH with the same method as YR1.
  • MH=[300, 1000]GeV for ggF and VBF with Passarino presciption as discussed in YR2 (Section 15).
  • Scanning points is defined by the LHC Higgs combination WG's note, ATL-PHYS-PUB-2011-11, CMS NOTE-2011/005, Table 1.
  • EXPs need numbers down to MH=80GeV as benchmark numbers for possible BSM physics.

Higgs Mass range step size # of points
[ 80,110] GeV 1 GeV 31 points
[110,140] GeV 0.5 GeV 60 points
[140,160] GeV 1 GeV 20 points
[160,290] GeV 2 GeV 65 points
[290,350] GeV 5 GeV 12 points
[350,400] GeV 10 GeV 5 points
[400,1000] GeV 20 GeV 30 points
+ 450, 550, 650, 750, 850, 950 GeV (6 points)
  • 229 points in total

Green led QCD scale uncertainty

  • It should be discussed in each subgroup how to estimate QCD scale uncertainty.
  • As these uncertainties change smoothly, it would be enough to do the coarse scan with following points.
  • Please carry out the interpolation with spline fit (or 3rd order polynomial fit) for other Higgs mass points.

* Scan example:

Higgs Mass range step size # of points
[80,200] GeV 5 GeV 25 points
[200,300] GeV 10 GeV 10 points
[300,1000] GeV 20 GeV 35 points
  • 70 points in total
>
>

Blue led Standard Model Input Parameter

 
Changed:
<
<
  • The factorization and the renormalization scales are process dependent and should be defined by each subgroup.
  • The scale uncertainty should also be defined by each group, (e.g.. 1/2MH < μR, μF < 2MH, do 2D scan with 1/2 < μRF < 2)

Orange led PDF+αs uncertainty calculations (a la PDF4LHC prescription)

>
>
<!--   * See also TWiki page. -->
 
Changed:
<
<
  • How to estimate PDF+αs uncertainty for 8TeV is under discussion by PDF experts.
>
>

 
Changed:
<
<

PDF sets

>
>

Red led 1. SM Higgs-boson production cross section calculation

 
Changed:
<
<
  1. For NLO calculations, CTEQ6.6, MSTW2008 and NNPDF2.0 are the default sets. Others, e.g. HERAPDF, ABKM and (G)JR are optional, but we recommend to calculate with these PDF sets as well.
  2. For NNLO calculations, MSTW2008 is the defalut set. We also recommend to compare MSTW with ABKM and (G)JR at NNLO.
>
>

Aqua led Mass scan: √s = 7 and 8 TeV (for updates) and 13 and 14 TeV

 
Changed:
<
<

Yellow led Cross section central values

>
>
  • 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, ccH
  • Only for MH=125.0 and 125.09 GeV for rare Higgs production processes (σ < O(100)fb) and rare Higgs decay channels:
    1. Associated Higgs with single top-quark: tH (bq->tHq', bg->WtH, qq->both)
    2. Higgs pair/triple production: HH, ttHH, qqHH, tjHH, VHH, VVHH, HHH (V=W,Z)
    3. Associated Higgs with gauge boson: VVH (V=γ,W,Z)
 
Changed:
<
<
  1. For NLO, take the midpoint of CTEQ6.6, MSTW2008 and NNPDF2.0 envelope following the recommendation from PDF4LHC group.
  2. For NNLO, take MSTW2008 result.
>
>

Mass range and step for SM-like Higgs boson:

 
Changed:
<
<

Purple led PDF+αs uncertainties (PDF4LHC group recommendation)

>
>
Higgs Mass range step size # of points addendum
[120,124] GeV 0.5 GeV 9 points  
[124,126] GeV 0.1 GeV 20 points + MH=125.09 GeV
[126,130] GeV 0.5 GeV 8 points  
  • Total 38 points for MH=[120,130] GeV.
  • Empirical function of cross section as a function of Higgs-boson mass should be provided.
 
Changed:
<
<
  • Δαs=+-0.0012 for 68%C.L. and Δαs=+-0.0020 for 90%C.L.
  • If calculations only at 90% C.L. calculation exist (CTEQ), we shall translate (i.e., by dividing 90%C.L. error by 1.645).
  • PDF+αs uncertainties should be calculated both at 68% C.L. (priority) and at 90% C.L..
>
>

Aqua led Ecm scan: √s = [6,15] TeV with 1 TeV step

 
Changed:
<
<
  1. The total PDF+αs uncertainty can be evaluated by adding the variations in PDFs due to αs uncertainty in quadrature with the fixed αs PDF uncertainty,
  2. For NNPDF, more efficiently taking a Gaussian distribution of PDF replicas corresponding to different values of αs.
  3. For MSTW, the PDF+ αs uncertainties should be evaluated using their prescription which better accounts for correlations between the PDF and αs uncertainties when using the MSTW dynamical tolerance procedure for uncertainties. Adding the αs uncertainty in quadrature for MSTW can be used as a simpli cation but generally gives slightly smaller uncertainties.
>
>
  • Ecm 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->both)
  • MH=125.0 GeV.
 
Deleted:
<
<
  1. For NLO, use the envelope provided by the central values and PDF+ αs errors from the MSTW08, CTEQ6.6 and NNPDF2.0 PDFs, using each group's prescriptions for combining the two types of errors. Take the symmetric error following the recommendation from PDF4LHC group.
  2. For NNLO, multiply the MSTW uncertainty at NNLO by the factor obtained by dividing the full PDF+αs uncertainty obtained from the envelope of MSTW, CTEQ and NNPDF results at NLO by the MSTW PDF+αs uncertainty at NLO (~ factor 2 at 7 TeV).
 
Added:
>
>

 
Changed:
<
<

Red led Recipe from PDF4LHC

>
>

Red led 2. BSM Higgs-boson production cross section calculation

 
Changed:
<
<
The official PDF4LHC recommendations on NLO/NNLO cross sections and PDF uncertainty estimations:
>
>

Aqua led Mass scan: √s = 7 and 8 TeV (for updates) and 13 and 14 TeV

 
Changed:
<
<
  1. Recommendation for LHC cross section calculations (June 22, 2010)
>
>
  • 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->both)
  • 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.
 
Changed:
<
<

Practical guide on PDF+ αs error calculation

>
>

Mass range and step for BSM Higgs boson:

 
Changed:
<
<
  1. Suggestions on calculating the PDF4LHC prescription (September 21, 2010)
>
>
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 MH=[10,3000] GeV.
  • Lower mass limit might depend on stability of the code at low Bjorken x. To be assessed.
 
Changed:
<
<
  1. MSTW: Check the first two paragraphs of section 6 in arXiv:0905.3531.
    • However adding in quadrature is a pretty good approximation if one is attempting to be quicker.
  2. CTEQ: Check section III-B in arXiv:1004.4624.
  3. NNPDF: Check arXiv:1004.0962.
>
>

 
Changed:
<
<
<!-- comment out following
>
>

Green led 3. QCD scale uncertainty

 
Changed:
<
<
Red led Recipe from PDF4LHC
>
>
  • It should be discussed in each subgroup how to estimate QCD scale uncertainty.
  • The factorization and the renormalization scales are process dependent and should be defined by each subgroup.
  • The scale uncertainty should also be defined by each group, (e.g.. 1/2MH < μR, μF < 2MH, do 2D scan with 1/2 < μRF < 2).
  • As these uncertainties change smoothly, it would be enough to do the coarse scan.
  • Please carry out the interpolation with spline fit (or 3rd order polynomial fit) for other Higgs mass points.
 
Deleted:
<
<
We had been asking the PDF4LHC working group to provide us a prescription on PDF sets, including
  • QCD αs central value with the associated error to be used,
  • Definitions of PDF+αs uncertainties and their treatments.
 
Changed:
<
<
We got the following recommendation from PDF4LHC group on May 19, 2010 :
>
>

Orange led 4. PDF+αs uncertainty calculations

 
Changed:
<
<
"For estimates of PDF uncertainties, our recommendation would be for experimenters to use (at least) predictions from the three PDF fits that are truly global, i.e. that use results from the Tevatron and fixed target experiments as well as HERA: CTEQ, MSTW and NNPDF. The use of other PDFs for predictions is optional. The benchmarking exercises are useful to understand the αs dependence of LHC cross sections, and to understand what differences among the PDF groups result from assumptions of different values of αs. For the calculation of uncertainties at the LHC, the recommendation is to use the envelope provided by the central values and PDF+αs errors from the above three groups."
>
>
 
Changed:
<
<
We finally got the official PDF4LHC recommendations on NLO/NNLO cross sections and PDF uncertainty estimations on June 22, 2010 :
>
>

PDF set

 
Changed:
<
<
Recommendation for LHC cross section calculations (Link to full recommendation)
>
>

PDF and QCD αs(MZ) uncertainties

  • QCD αs(MZ) should be set as 0.1180+-0.0015.
 
Changed:
<
<
"Recommendation for LHC cross section calculations: The LHC experiments are currently producing cross sections from the 7 TeV data, and thus need accurate predictions for these cross sections and their uncertainties at NLO and NNLO. Crucial to the predictions and their uncertainties are the parton distribution functions (PDFs) obtained from global fits to data from deep-inelastic scattering, Drell-Yan and jet data. A number of groups have produced publicly available PDFs using different data sets and analysis frameworks. Given the necessity of having an official recommendation from the PDF4LHC working group available on a short time frame, the prescription outlined at the the link below has been adopted. This is not intended to be an ideal or a final prescription, but is considered to be reasonably conservative and reasonably easy to implement. Further improvements and further standardizations are planned for future updates."
>
>
 
Deleted:
<
<
!-->
 
Changed:
<
<
-- ReiTanaka - 21-May-2010
>
>
-- ReiTanaka - 19-Nov-2015
 
Changed:
<
<
META FILEATTACHMENT attachment="PDF_error.pdf" attr="" comment="PDF+alpha_s error calculation methods" date="1285157425" name="PDF_error.pdf" path="PDF_error.pdf" size="46363" stream="PDF_error.pdf" tmpFilename="/usr/tmp/CGItemp60449" user="tanaka" version="1"
META FILEATTACHMENT attachment="PDF4LHCrecom.pdf" attr="" comment="PDF4LHC recipe" date="1285159410" name="PDF4LHCrecom.pdf" path="PDF4LHCrecom.pdf" size="56868" stream="PDF4LHCrecom.pdf" tmpFilename="/usr/tmp/CGItemp55290" user="tanaka" version="1"
>
>
META FILEATTACHMENT attachment="HXS4BSM_v0.5.pdf" attr="" comment="" date="1447949960" name="HXS4BSM_v0.5.pdf" path="HXS4BSM_v0.5.pdf" size="87688" user="tanaka" version="1"
 
META TOPICMOVED by="tanaka" date="1415032114" from="LHCPhysics.CrossSectionsCalc" to="LHCPhysics.LHCHXSWGCrossSectionsCalc"

Revision 202014-11-06 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="LHCHXSWG"
<!--
Changed:
<
<
>
>
 
-->

Higgs Cross Section Calculation at 7, 8 and 14 TeV

Revision 192014-11-04 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="LHCHXSWG"
<!--  
Line: 60 to 60
 

PDF sets

Changed:
<
<
  • PDF prescriptions can be found here.
>
>
  • PDF prescriptions can be found here.
 

  1. For NLO calculations, CTEQ6.6, MSTW2008 and NNPDF2.0 are the default sets. Others, e.g. HERAPDF, ABKM and (G)JR are optional, but we recommend to calculate with these PDF sets as well.
Line: 94 to 94
 

Practical guide on PDF+ αs error calculation

  1. Suggestions on calculating the PDF4LHC prescription (September 21, 2010)
Changed:
<
<
>
>
 
  1. MSTW: Check the first two paragraphs of section 6 in arXiv:0905.3531.
    • However adding in quadrature is a pretty good approximation if one is attempting to be quicker.

Revision 182014-11-03 - ReiTanaka

Line: 1 to 1
Changed:
<
<
META TOPICPARENT name="CrossSections"
>
>
META TOPICPARENT name="LHCHXSWG"
 
<!--  
-->
Line: 16 to 16
 

Blue led Standard Model input parameter

  • Input parameters for 8TeV calculations are the same as YR1.
Changed:
<
<
>
>
 

Gray led Higgs mass range and step:

Line: 61 to 61
 
Changed:
<
<
>
>
 
  1. For NLO calculations, CTEQ6.6, MSTW2008 and NNPDF2.0 are the default sets. Others, e.g. HERAPDF, ABKM and (G)JR are optional, but we recommend to calculate with these PDF sets as well.
  2. For NNLO calculations, MSTW2008 is the defalut set. We also recommend to compare MSTW with ABKM and (G)JR at NNLO.
Line: 128 to 128
 
META FILEATTACHMENT attachment="PDF_error.pdf" attr="" comment="PDF+alpha_s error calculation methods" date="1285157425" name="PDF_error.pdf" path="PDF_error.pdf" size="46363" stream="PDF_error.pdf" tmpFilename="/usr/tmp/CGItemp60449" user="tanaka" version="1"
META FILEATTACHMENT attachment="PDF4LHCrecom.pdf" attr="" comment="PDF4LHC recipe" date="1285159410" name="PDF4LHCrecom.pdf" path="PDF4LHCrecom.pdf" size="56868" stream="PDF4LHCrecom.pdf" tmpFilename="/usr/tmp/CGItemp55290" user="tanaka" version="1"
Changed:
<
<
META TOPICMOVED by="tanaka" date="1286617169" from="LHCPhysics.CrossSections7TeV" to="LHCPhysics.CrossSectionsCalc"
>
>
META TOPICMOVED by="tanaka" date="1415032114" from="LHCPhysics.CrossSectionsCalc" to="LHCPhysics.LHCHXSWGCrossSectionsCalc"

Revision 172014-10-27 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="CrossSections"
<!--
Changed:
<
<
Set ALLOWTOPICCHANGE=ChiaraMariotti,ReiTanaka
>
>
 
-->

Higgs Cross Section Calculation at 7, 8 and 14 TeV

Revision 162014-10-19 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="CrossSections"
<!--
Changed:
<
<
* Set ALLOWTOPICCHANGE=ChiaraMariotti,ReiTanaka
>
>
Set ALLOWTOPICCHANGE=ChiaraMariotti,ReiTanaka
 
-->

Higgs Cross Section Calculation at 7, 8 and 14 TeV

Revision 152012-04-06 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="CrossSections"
Added:
>
>
<!--
  * Set ALLOWTOPICCHANGE=ChiaraMariotti,ReiTanaka
-->
 

Higgs Cross Section Calculation at 7, 8 and 14 TeV

Help This is the instruction for Higgs cross section calculations at centre-of-mass energy of 7, 8 and 14 TeV.

Revision 142012-02-18 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="CrossSections"

Higgs Cross Section Calculation at 7, 8 and 14 TeV

Line: 11 to 11
 

Aqua led Centre-of-mass Energy = 7, 8 and 14 TeV

Blue led Standard Model input parameter

Added:
>
>
  • Input parameters for 8TeV calculations are the same as YR1.
 

Gray led Higgs mass range and step:

Changed:
<
<
  • MH=[80GeV, 1TeV] for ggF and VBF, and MH=[80GeV, 300GeV] for WH/ZH and ttH.
>
>
  • MH=[80, 300]GeV for ggF, VBF, WH/ZH and ttH with the same method as YR1.
  • MH=[300, 1000]GeV for ggF and VBF with Passarino presciption as discussed in YR2 (Section 15).
 
Line: 30 to 32
 + 450, 550, 650, 750, 850, 950 GeV (6 points)
  • 229 points in total
Changed:
<
<

QDD scale and PDF+αs uncertainty calculations (a la PDF4LHC prescription)

>
>

Green led QCD scale uncertainty

 
Added:
>
>
  • It should be discussed in each subgroup how to estimate QCD scale uncertainty.
 
  • As these uncertainties change smoothly, it would be enough to do the coarse scan with following points.
  • Please carry out the interpolation with spline fit (or 3rd order polynomial fit) for other Higgs mass points.
Added:
>
>
* Scan example:
 
Higgs Mass range step size # of points
[80,200] GeV 5 GeV 25 points
[200,300] GeV 10 GeV 10 points
[300,1000] GeV 20 GeV 35 points
  • 70 points in total
Changed:
<
<

Orange led PDF sets

>
>
  • The factorization and the renormalization scales are process dependent and should be defined by each subgroup.
  • The scale uncertainty should also be defined by each group, (e.g.. 1/2MH < μR, μF < 2MH, do 2D scan with 1/2 < μRF < 2)

Orange led PDF+αs uncertainty calculations (a la PDF4LHC prescription)

  • How to estimate PDF+αs uncertainty for 8TeV is under discussion by PDF experts.

PDF sets

 
Line: 50 to 62
 
  1. For NLO calculations, CTEQ6.6, MSTW2008 and NNPDF2.0 are the default sets. Others, e.g. HERAPDF, ABKM and (G)JR are optional, but we recommend to calculate with these PDF sets as well.
  2. For NNLO calculations, MSTW2008 is the defalut set. We also recommend to compare MSTW with ABKM and (G)JR at NNLO.
Changed:
<
<

Yellow led Cross section central values

>
>

Yellow led Cross section central values

 
  1. For NLO, take the midpoint of CTEQ6.6, MSTW2008 and NNPDF2.0 envelope following the recommendation from PDF4LHC group.
  2. For NNLO, take MSTW2008 result.
Changed:
<
<

Green led QCD scale uncertainty

The factorization and the renormalization scales are process dependent and should be defined by each subgroup. The scale uncertainty should also be defined by each group, (e.g.. 1/2MH < μR, μF < 2MH, do 2D scan with 1/2 < μRF < 2)

Purple led PDF+αs uncertainties (PDF4LHC group recommendation)

>
>

Purple led PDF+αs uncertainties (PDF4LHC group recommendation)

 
  • Δαs=+-0.0012 for 68%C.L. and Δαs=+-0.0020 for 90%C.L.
  • If calculations only at 90% C.L. calculation exist (CTEQ), we shall translate (i.e., by dividing 90%C.L. error by 1.645).

Revision 132012-02-17 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="CrossSections"

Higgs Cross Section Calculation at 7, 8 and 14 TeV

Line: 15 to 15
 

Gray led Higgs mass range and step:

Changed:
<
<
  • MH=[90GeV, 1TeV] or up to meaningful Higgs mass for each production process (MH<300GeV for WH/ZH and ttH)
>
>
  • MH=[80GeV, 1TeV] for ggF and VBF, and MH=[80GeV, 300GeV] for WH/ZH and ttH.
 
Added:
>
>
  • EXPs need numbers down to MH=80GeV as benchmark numbers for possible BSM physics.
 
Changed:
<
<
Higgs Mass range step size
[ 80,110] GeV 1 GeV
[110,140] GeV 0.5 GeV
[140,160] GeV 1 GeV
[160,290] GeV 2 GeV
[290,350] GeV 5 GeV
[350,400] GeV 10 GeV
[400,1000] GeV 20 GeV
+ 450, 550, 650, 750, 850, 950 GeV
>
>
Higgs Mass range step size # of points
[ 80,110] GeV 1 GeV 31 points
[110,140] GeV 0.5 GeV 60 points
[140,160] GeV 1 GeV 20 points
[160,290] GeV 2 GeV 65 points
[290,350] GeV 5 GeV 12 points
[350,400] GeV 10 GeV 5 points
[400,1000] GeV 20 GeV 30 points
+ 450, 550, 650, 750, 850, 950 GeV (6 points)
  • 229 points in total
 

QDD scale and PDF+αs uncertainty calculations (a la PDF4LHC prescription)

  • As these uncertainties change smoothly, it would be enough to do the coarse scan with following points.
  • Please carry out the interpolation with spline fit (or 3rd order polynomial fit) for other Higgs mass points.
Changed:
<
<
Higgs Mass range step size
[80,200] GeV 5 GeV
[200,300] GeV 10 GeV
[300,400] GeV 20 GeV
[400,1000] GeV 20 GeV
>
>
Higgs Mass range step size # of points
[80,200] GeV 5 GeV 25 points
[200,300] GeV 10 GeV 10 points
[300,1000] GeV 20 GeV 35 points
  • 70 points in total
 

Orange led PDF sets

Revision 122012-02-17 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="CrossSections"

Higgs Cross Section Calculation at 7, 8 and 14 TeV

Line: 19 to 19
 

Higgs Mass range step size
Changed:
<
<
[ 90,140] GeV 0.5 GeV
>
>
[ 80,110] GeV 1 GeV
[110,140] GeV 0.5 GeV
 
[140,160] GeV 1 GeV
[160,290] GeV 2 GeV
[290,350] GeV 5 GeV
[350,400] GeV 10 GeV
[400,1000] GeV 20 GeV
Added:
>
>
+ 450, 550, 650, 750, 850, 950 GeV
 

QDD scale and PDF+αs uncertainty calculations (a la PDF4LHC prescription)

Line: 32 to 34
 
  • Please carry out the interpolation with spline fit (or 3rd order polynomial fit) for other Higgs mass points.

Higgs Mass range step size
Changed:
<
<
[90,200] GeV 5 GeV
>
>
[80,200] GeV 5 GeV
 
[200,300] GeV 10 GeV
[300,400] GeV 20 GeV
[400,1000] GeV 20 GeV

Revision 112012-02-14 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="CrossSections"

Higgs Cross Section Calculation at 7, 8 and 14 TeV

Line: 15 to 15
 

Gray led Higgs mass range and step:

Changed:
<
<
  • MH=[90GeV, 1TeV] or up to meaningful Higgs mass for each production process
>
>
  • MH=[90GeV, 1TeV] or up to meaningful Higgs mass for each production process (MH<300GeV for WH/ZH and ttH)
  • Scanning points is defined by the LHC Higgs combination WG's note, ATL-PHYS-PUB-2011-11, CMS NOTE-2011/005, Table 1.

Higgs Mass range step size
[ 90,140] GeV 0.5 GeV
[140,160] GeV 1 GeV
[160,290] GeV 2 GeV
[290,350] GeV 5 GeV
[350,400] GeV 10 GeV
[400,1000] GeV 20 GeV

QDD scale and PDF+αs uncertainty calculations (a la PDF4LHC prescription)

  • As these uncertainties change smoothly, it would be enough to do the coarse scan with following points.
  • Please carry out the interpolation with spline fit (or 3rd order polynomial fit) for other Higgs mass points.
 
Higgs Mass range step size
[90,200] GeV 5 GeV
[200,300] GeV 10 GeV
[300,400] GeV 20 GeV
Changed:
<
<
[400,1000] GeV 50 GeV
>
>
[400,1000] GeV 20 GeV
 

Orange led PDF sets

Revision 102012-02-13 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="CrossSections"
Changed:
<
<

Higgs Cross Section Calculation at 7 and 14 TeV

>
>

Higgs Cross Section Calculation at 7, 8 and 14 TeV

 
Changed:
<
<
Help This is the instruction for Higgs cross section calculations at centre-of-mass energy of 7 TeV.
>
>
Help This is the instruction for Higgs cross section calculations at centre-of-mass energy of 7, 8 and 14 TeV.
  Complete inclusive cross sections at LO, NLO and NNLO(+NNLL) should be calculated.

Changed:
<
<

Aqua led Centre-of-mass Energy = 7 and 14 TeV

>
>

Aqua led Centre-of-mass Energy = 7, 8 and 14 TeV

 

Blue led Standard Model input parameter

Revision 92010-12-25 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="CrossSections"

Higgs Cross Section Calculation at 7 and 14 TeV

Revision 82010-10-09 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="CrossSections"

Higgs Cross Section Calculation at 7 and 14 TeV

Line: 62 to 62
 The official PDF4LHC recommendations on NLO/NNLO cross sections and PDF uncertainty estimations:

  1. Recommendation for LHC cross section calculations (June 22, 2010)
Changed:
<
<
  1. Suggestions on calculating the PDF4LHC prescription (September 21, 2010)
>
>

Practical guide on PDF+ αs error calculation

  1. Suggestions on calculating the PDF4LHC prescription (September 21, 2010)

  1. MSTW: Check the first two paragraphs of section 6 in arXiv:0905.3531.
    • However adding in quadrature is a pretty good approximation if one is attempting to be quicker.
  2. CTEQ: Check section III-B in arXiv:1004.4624.
  3. NNPDF: Check arXiv:1004.0962.
 
<!-- comment out following
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>
META TOPICMOVED by="tanaka" date="1286617169" from="LHCPhysics.CrossSections7TeV" to="LHCPhysics.CrossSectionsCalc"

Revision 72010-09-22 - ReiTanaka

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META TOPICPARENT name="CrossSections"
Changed:
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<

Higgs Cross Section Calculation at 7 TeV

>
>

Higgs Cross Section Calculation at 7 and 14 TeV

  Help This is the instruction for Higgs cross section calculations at centre-of-mass energy of 7 TeV.
Line: 8 to 8
 
Changed:
<
<

Aqua led Centre-of-mass Energy = 7 TeV

>
>

Aqua led Centre-of-mass Energy = 7 and 14 TeV

 

Blue led Standard Model input parameter

Line: 56 to 56
 
  1. For NLO, use the envelope provided by the central values and PDF+ αs errors from the MSTW08, CTEQ6.6 and NNPDF2.0 PDFs, using each group's prescriptions for combining the two types of errors. Take the symmetric error following the recommendation from PDF4LHC group.
  2. For NNLO, multiply the MSTW uncertainty at NNLO by the factor obtained by dividing the full PDF+αs uncertainty obtained from the envelope of MSTW, CTEQ and NNPDF results at NLO by the MSTW PDF+αs uncertainty at NLO (~ factor 2 at 7 TeV).
Added:
>
>
 

Red led Recipe from PDF4LHC

Added:
>
>
The official PDF4LHC recommendations on NLO/NNLO cross sections and PDF uncertainty estimations:

  1. Recommendation for LHC cross section calculations (June 22, 2010)
  2. Suggestions on calculating the PDF4LHC prescription (September 21, 2010)

<!-- comment out following

Red led Recipe from PDF4LHC

 We had been asking the PDF4LHC working group to provide us a prescription on PDF sets, including
  • QCD αs central value with the associated error to be used,
  • Definitions of PDF+αs uncertainties and their treatments.
Line: 73 to 83
  "Recommendation for LHC cross section calculations: The LHC experiments are currently producing cross sections from the 7 TeV data, and thus need accurate predictions for these cross sections and their uncertainties at NLO and NNLO. Crucial to the predictions and their uncertainties are the parton distribution functions (PDFs) obtained from global fits to data from deep-inelastic scattering, Drell-Yan and jet data. A number of groups have produced publicly available PDFs using different data sets and analysis frameworks. Given the necessity of having an official recommendation from the PDF4LHC working group available on a short time frame, the prescription outlined at the the link below has been adopted. This is not intended to be an ideal or a final prescription, but is considered to be reasonably conservative and reasonably easy to implement. Further improvements and further standardizations are planned for future updates."
Added:
>
>
!-->
 

-- ReiTanaka - 21-May-2010

Added:
>
>
META FILEATTACHMENT attachment="PDF_error.pdf" attr="" comment="PDF+alpha_s error calculation methods" date="1285157425" name="PDF_error.pdf" path="PDF_error.pdf" size="46363" stream="PDF_error.pdf" tmpFilename="/usr/tmp/CGItemp60449" user="tanaka" version="1"
META FILEATTACHMENT attachment="PDF4LHCrecom.pdf" attr="" comment="PDF4LHC recipe" date="1285159410" name="PDF4LHCrecom.pdf" path="PDF4LHCrecom.pdf" size="56868" stream="PDF4LHCrecom.pdf" tmpFilename="/usr/tmp/CGItemp55290" user="tanaka" version="1"

Revision 62010-06-24 - ReiTanaka

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META TOPICPARENT name="CrossSections"

Higgs Cross Section Calculation at 7 TeV

Line: 34 to 34
 

Yellow led Cross section central values

Changed:
<
<
  1. For NLO, take the midpoint of CTEQ6.6, MSTW2008 and NNPDF2.0.
>
>
  1. For NLO, take the midpoint of CTEQ6.6, MSTW2008 and NNPDF2.0 envelope following the recommendation from PDF4LHC group.
 
  1. For NNLO, take MSTW2008 result.

Green led QCD scale uncertainty

Line: 53 to 53
 
  1. For NNPDF, more efficiently taking a Gaussian distribution of PDF replicas corresponding to different values of αs.
  2. For MSTW, the PDF+ αs uncertainties should be evaluated using their prescription which better accounts for correlations between the PDF and αs uncertainties when using the MSTW dynamical tolerance procedure for uncertainties. Adding the αs uncertainty in quadrature for MSTW can be used as a simpli cation but generally gives slightly smaller uncertainties.
Changed:
<
<
  1. For NLO, use the envelope provided by the central values and PDF+ αs errors from the MSTW08, CTEQ6.6 and NNPDF2.0 PDFs, using each group's prescriptions for combining the two types of errors.
>
>
  1. For NLO, use the envelope provided by the central values and PDF+ αs errors from the MSTW08, CTEQ6.6 and NNPDF2.0 PDFs, using each group's prescriptions for combining the two types of errors. Take the symmetric error following the recommendation from PDF4LHC group.
 
  1. For NNLO, multiply the MSTW uncertainty at NNLO by the factor obtained by dividing the full PDF+αs uncertainty obtained from the envelope of MSTW, CTEQ and NNPDF results at NLO by the MSTW PDF+αs uncertainty at NLO (~ factor 2 at 7 TeV).

Red led Recipe from PDF4LHC

Revision 52010-06-24 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="CrossSections"

Higgs Cross Section Calculation at 7 TeV

Line: 47 to 47
 
  • Δαs=+-0.0012 for 68%C.L. and Δαs=+-0.0020 for 90%C.L.
  • If calculations only at 90% C.L. calculation exist (CTEQ), we shall translate (i.e., by dividing 90%C.L. error by 1.645).
Changed:
<
<
  • PDF+αs uncertainties should be calculated both at 68% C.L. and 90% C.L..
>
>
  • PDF+αs uncertainties should be calculated both at 68% C.L. (priority) and at 90% C.L..
 
  1. The total PDF+αs uncertainty can be evaluated by adding the variations in PDFs due to αs uncertainty in quadrature with the fixed αs PDF uncertainty,
  2. For NNPDF, more efficiently taking a Gaussian distribution of PDF replicas corresponding to different values of αs.

Revision 42010-06-23 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="CrossSections"

Higgs Cross Section Calculation at 7 TeV

Line: 23 to 23
 
[300,400] GeV 20 GeV
[400,1000] GeV 50 GeV
Changed:
<
<

Green led PDF sets

>
>

Orange led PDF sets

 
Added:
>
>
  • All these PDF sets are on LHAPDF.
 
Changed:
<
<
CTEQ, MSTW and NNPDF are the default sets for NLO calculations. Others, e.g. HERAPDF, ABKM and (G)JR are optional, but we recommend to calculate with these PDF sets as well. In particular, we need to compare MSTW with ABKM and (G)JR at NNLO. All these sets are on LHAPDF.
>
>
  1. For NLO calculations, CTEQ6.6, MSTW2008 and NNPDF2.0 are the default sets. Others, e.g. HERAPDF, ABKM and (G)JR are optional, but we recommend to calculate with these PDF sets as well.
  2. For NNLO calculations, MSTW2008 is the defalut set. We also recommend to compare MSTW with ABKM and (G)JR at NNLO.
 
Changed:
<
<

Orange led QCD scale uncertainty

>
>

Yellow led Cross section central values

  1. For NLO, take the midpoint of CTEQ6.6, MSTW2008 and NNPDF2.0.
  2. For NNLO, take MSTW2008 result.

Green led QCD scale uncertainty

  The factorization and the renormalization scales are process dependent and should be defined by each subgroup. The scale uncertainty should also be defined by each group, (e.g.. 1/2MH < μR, μF < 2MH, do 2D scan with 1/2 < μRF < 2)
Changed:
<
<

Purple led PDF, PDF+αs uncertainties

>
>

Purple led PDF+αs uncertainties (PDF4LHC group recommendation)

  • Δαs=+-0.0012 for 68%C.L. and Δαs=+-0.0020 for 90%C.L.
  • If calculations only at 90% C.L. calculation exist (CTEQ), we shall translate (i.e., by dividing 90%C.L. error by 1.645).
  • PDF+αs uncertainties should be calculated both at 68% C.L. and 90% C.L..
 
Changed:
<
<
The PDF error with/without αs error both at 68% and 90% C.L. should be calculated. If 68% C.L. calculation does not exist, we shall translate (e,g, by dividing 90%C.L. error by 1.64885).
>
>
  1. The total PDF+αs uncertainty can be evaluated by adding the variations in PDFs due to αs uncertainty in quadrature with the fixed αs PDF uncertainty,
  2. For NNPDF, more efficiently taking a Gaussian distribution of PDF replicas corresponding to different values of αs.
  3. For MSTW, the PDF+ αs uncertainties should be evaluated using their prescription which better accounts for correlations between the PDF and αs uncertainties when using the MSTW dynamical tolerance procedure for uncertainties. Adding the αs uncertainty in quadrature for MSTW can be used as a simpli cation but generally gives slightly smaller uncertainties.
 
Changed:
<
<

Red led Recipe from PDF4LHC

>
>
  1. For NLO, use the envelope provided by the central values and PDF+ αs errors from the MSTW08, CTEQ6.6 and NNPDF2.0 PDFs, using each group's prescriptions for combining the two types of errors.
  2. For NNLO, multiply the MSTW uncertainty at NNLO by the factor obtained by dividing the full PDF+αs uncertainty obtained from the envelope of MSTW, CTEQ and NNPDF results at NLO by the MSTW PDF+αs uncertainty at NLO (~ factor 2 at 7 TeV).
 
Changed:
<
<
We had been asking the PDF4LHC working group to provide us a prescription on PDF sets, including
>
>

Red led Recipe from PDF4LHC

We had been asking the PDF4LHC working group to provide us a prescription on PDF sets, including

 
  • QCD αs central value with the associated error to be used,
  • Definitions of PDF+αs uncertainties and their treatments.
Changed:
<
<
We got the following recommendation from PDF4LHC group on May 19, 2010 :
>
>
We got the following recommendation from PDF4LHC group on May 19, 2010 :
  "For estimates of PDF uncertainties, our recommendation would be for experimenters to use (at least) predictions from the three PDF fits that are truly global, i.e. that use results from the Tevatron and fixed target experiments as well as HERA: CTEQ, MSTW and NNPDF. The use of other PDFs for predictions is optional. The benchmarking exercises are useful to understand the αs dependence of LHC cross sections, and to understand what differences among the PDF groups result from assumptions of different values of αs. For the calculation of uncertainties at the LHC, the recommendation is to use the envelope provided by the central values and PDF+αs errors from the above three groups."
Added:
>
>
We finally got the official PDF4LHC recommendations on NLO/NNLO cross sections and PDF uncertainty estimations on June 22, 2010 :

Recommendation for LHC cross section calculations (Link to full recommendation)

"Recommendation for LHC cross section calculations: The LHC experiments are currently producing cross sections from the 7 TeV data, and thus need accurate predictions for these cross sections and their uncertainties at NLO and NNLO. Crucial to the predictions and their uncertainties are the parton distribution functions (PDFs) obtained from global fits to data from deep-inelastic scattering, Drell-Yan and jet data. A number of groups have produced publicly available PDFs using different data sets and analysis frameworks. Given the necessity of having an official recommendation from the PDF4LHC working group available on a short time frame, the prescription outlined at the the link below has been adopted. This is not intended to be an ideal or a final prescription, but is considered to be reasonably conservative and reasonably easy to implement. Further improvements and further standardizations are planned for future updates."

 

Revision 32010-06-02 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="CrossSections"

Higgs Cross Section Calculation at 7 TeV

Line: 26 to 24
 
[400,1000] GeV 50 GeV

Green led PDF sets

Changed:
<
<

CTEQ, MSTW and NNPDF are the default sets for NLO calculations. Others, e.g. HERAPDF, ABKM and JR are optional, but we recommend to calculate with these PDF sets as well. In particular, we need to compare MSTW with ABKM and JR at NNLO. All these sets are on LHAPDF.

>
>

CTEQ, MSTW and NNPDF are the default sets for NLO calculations. Others, e.g. HERAPDF, ABKM and (G)JR are optional, but we recommend to calculate with these PDF sets as well. In particular, we need to compare MSTW with ABKM and (G)JR at NNLO. All these sets are on LHAPDF.

 
Changed:
<
<

Orange led QCD scale uncertainty

>
>

Orange led QCD scale uncertainty

  The factorization and the renormalization scales are process dependent and should be defined by each subgroup. The scale uncertainty should also be defined by each group,
Line: 44 to 43
 The PDF error with/without αs error both at 68% and 90% C.L. should be calculated. If 68% C.L. calculation does not exist, we shall translate (e,g, by dividing 90%C.L. error by 1.64885).
Changed:
<
<

Red led Recipe from PDF4LHC

>
>

Red led Recipe from PDF4LHC

 
Changed:
<
<
We had been asking the PDF4LHC working group to provide us a prescription on PDF sets, including
  • QCD αs central value with the associated error to be used,
>
>
We had been asking the PDF4LHC working group to provide us a prescription on PDF sets, including
  • QCD αs central value with the associated error to be used,
 
  • Definitions of PDF+αs uncertainties and their treatments.
Changed:
<
<
We got the following recommendation from PDF4LHC group on May 19, 2010 :
>
>
We got the following recommendation from PDF4LHC group on May 19, 2010 :
 
Changed:
<
<
"For estimates of PDF uncertainties, our recommendation would be for experimenters to use (at least) predictions from the three PDF fits that are truly global, i.e. that use results from the Tevatron and fixed target experiments as well as HERA: CTEQ, MSTW and NNPDF. The use of other PDFs for predictions is optional. The benchmarking exercises are useful to understand the αs dependence of LHC cross sections, and to understand what differences among the PDF groups result from assumptions of different values of αs. For the calculation of uncertainties at the LHC, the recommendation is to use the envelope provided by the central values and PDF+αs errors from the above three groups."
>
>
"For estimates of PDF uncertainties, our recommendation would be for experimenters to use (at least) predictions from the three PDF fits that are truly global, i.e. that use results from the Tevatron and fixed target experiments as well as HERA: CTEQ, MSTW and NNPDF. The use of other PDFs for predictions is optional. The benchmarking exercises are useful to understand the αs dependence of LHC cross sections, and to understand what differences among the PDF groups result from assumptions of different values of αs. For the calculation of uncertainties at the LHC, the recommendation is to use the envelope provided by the central values and PDF+αs errors from the above three groups."
 


Revision 22010-06-02 - ReiTanaka

Line: 1 to 1
 
META TOPICPARENT name="CrossSections"
Changed:
<
<

Cross Section Calculation at 7 TeV

>
>

Higgs Cross Section Calculation at 7 TeV

 
Changed:
<
<
Help This is the standard recipe for Higgs cross section calculations for centre-of-mass energy of 7 TeV.
>
>
Help This is the instruction for Higgs cross section calculations at centre-of-mass energy of 7 TeV.
 
Changed:
<
<
We had been asking the PDF4LHC working group to provide us a prescription on PDF sets, including - QCD alpha_s central value with the associated error to be used, - Definitions of PDF+alpha_s uncertainties and their treatments.

We got the following recommendation from PDF4LHC group on May 19, 2010 :

"For estimates of PDF uncertainties, our recommendation would be for experimenters to use (at least) predictions from the three PDF fits that are truly global, i.e. that use results from the Tevatron and fixed target experiments as well as HERA: CTEQ, MSTW and NNPDF. The use of other PDFs for predictions is optional. The benchmarking exercises are useful to understand the alpha_s dependence of LHC cross sections, and to understand what differences among the PDF groups result from assumptions of different values of alphas. For the calculation of uncertainties at the LHC, the recommendation is to use the envelope provided by the central values and PDF+alpha_s errors from the above three groups."

Since our next workshop at CERN (July 5-6) is approaching, we overall contacts want to ask each subgroup to start the corresponding calculations within the following scheme (we will put this recipe onto our TWiki page).

>
>
Complete inclusive cross sections at LO, NLO and NNLO(+NNLL) should be calculated.
 
Changed:
<
<

Aqua led Centre-of-mass Energy

  1. TeV
>
>

Aqua led Centre-of-mass Energy = 7 TeV

 
Deleted:
<
<

Complete inclusive cross sections at LO, NLO and NNLO(+NNLL)

 
Deleted:
<
<

Standard Model input parameter from

https://twiki.cern.ch/twiki/bin/view/LHCPhysics/SMInputParameter
 
Changed:
<
<

Higgs mass range:

>
>

Blue led Standard Model input parameter

 
Changed:
<
<
MH=[90GeV, 1TeV] or up to meaningful Higgs mass for each production process
>
>

Gray led Higgs mass range and step:

 
Changed:
<
<
Δ =5GeV for [90,200]GeV
step=10GeV for [200,300]GeV step=20GeV for [300,400]GeV step=50GeV for [400,1000]GeV
>
>
  • MH=[90GeV, 1TeV] or up to meaningful Higgs mass for each production process
 
Changed:
<
<
- QCD alpha_s: Use default values of each PDF set
>
>
Higgs Mass range step size
[90,200] GeV 5 GeV
[200,300] GeV 10 GeV
[300,400] GeV 20 GeV
[400,1000] GeV 50 GeV
 
Changed:
<
<
- PDF sets: CTEQ6.6, MSTW2008, NNPDF2.0, HERAPDF1.0, ABKM09, GJR08
>
>

Green led PDF sets

 
Changed:
<
<
CTEQ, MSTW and NNPDF are the default sets for NLO calculations. Other, e.g. HERAPDF, ABKM and GJR are optional, but we recommend to calculate with these PDF sets as well. In particular, we need to compare MSTW with ABKM and GJR at NNLO. These sets are on LHAPDF.
>
>
CTEQ, MSTW and NNPDF are the default sets for NLO calculations. Others, e.g. HERAPDF, ABKM and JR are optional, but we recommend to calculate with these PDF sets as well. In particular, we need to compare MSTW with ABKM and JR at NNLO. All these sets are on LHAPDF.
 
Changed:
<
<
- QCD scale uncertainty:
>
>

Orange led QCD scale uncertainty

 
Changed:
<
<
The factorization and the renormalization scales are process dependent and should be defined by each subgroup.
>
>
The factorization and the renormalization scales are process dependent and should be defined by each subgroup.
  The scale uncertainty should also be defined by each group,
Changed:
<
<
(e.g.. 1/2MH < mu_R, mu_F < 2MH, do 2D scan with 1/2 < mu_R/mu_F < 2)
>
>
(e.g.. 1/2MH < μR, μF < 2MH, do 2D scan with 1/2 < μRF < 2)
 
Changed:
<
<
- PDF, PDF+alpha_s uncertainties:
>
>

Purple led PDF, PDF+αs uncertainties

 
Changed:
<
<
The PDF error with/without alpha_s error both at 68% and 90% C.L. should be calculated.
>
>
The PDF error with/without αs error both at 68% and 90% C.L. should be calculated.
  If 68% C.L. calculation does not exist, we shall translate (e,g, by dividing 90%C.L. error by 1.64885).
Changed:
<
<

The numbers are supposed to be the final one and ready for the next workshop at CERN. Once we complete these calculations and results are available, we shall discuss (e.g. before/at CERN) how to define the cross section central values and their associated errors.

e μ τ
0.510998910(13) MeV 105.658367(4) MeV 1776.84(17) MeV
u c t
190 MeV 1.40 GeV 172.5 +- 2.5 GeV
d s b
190 MeV 190 MeV 4.75 GeV

* Note: The charm and bottom masses are the pole masses used in the MSTW2008 PDF set.

Light quark masses

Light quark masses as used in parton show Monte Carlos are in some cases (e.g.HERWIG) effective masses used to regulate the parton shower in the infrared region (HERWIG also uses massive gluons), and as such may be treated more as a semi-perturbative QCD model parameter specific to a given generator rather than a SM parameter.

Charm and Bottom quark masses

We propose a process dependent choice of the quark masses since this issue cannot be generalized. The best choice should be given depending on the process. The current best fits for the MSbar masses are (arXiv:1001.5173),
MSbar mass mc(mc) mb(mb)
  1.28 GeV 4.16 GeV
These MSbar masses are obtained from fits to the QCD sum rules in charmonium and bottomonium systems and should normally be considered as the primary input. One could start from the MSbar values and compute the needed mass. The pole masses obtained from the values above strongly depend on the order of the calculation:
pole mass mc mb
1-loop 1.41 GeV 4.49 GeV
2-loop 1.55 GeV 4.69 GeV
On the other hand if we are going to use MSTW2008 PDFs, we are forced to use 4.75 GeV as the bottom pole mass. This should correspond to the 1-loop pole mass. Whatever we do, we are always forced to make a compromise due to consistency, i.e. to use mass values fitted at the order at which your observable is calculated and to be consistent with the input, in particular with the PDFs.

(Comments from Michael Spira, February, 2010).

Green led Gauge Boson Masses

W MW ΓW
  80.398(25) GeV 2.141(41) GeV
Z MZ ΓZ
  91.1876(21) GeV 2.4952(23) GeV
>
>

Red led Recipe from PDF4LHC

 
Changed:
<
<

>
>
We had been asking the PDF4LHC working group to provide us a prescription on PDF sets, including
  • QCD αs central value with the associated error to be used,
  • Definitions of PDF+αs uncertainties and their treatments.
 
Changed:
<
<

Orange led Electroweak Radiative Corrections

Gμ 1.16637(1)x10-5 GeV-2
>
>
We got the following recommendation from PDF4LHC group on May 19, 2010 :
 
Changed:
<
<
For EW radiative corrections, it is more complicated than QCD because of renormalization and the treatment of unstable particles are complicated. For the treatment of resonances complex-mass scheme, fixed-width scheme and pole-mass scheme can be taken. Also for the renormalization scheme which defines relations between electroweak couplings and parameters beyond the leading order, various schemes exist such as α(0) scheme, α(MZ2) scheme and the GF scheme. For further detail, please refer to the Binoth Les Houches Accord arXiv:1001.1307, Section 5.1 - 5.3.. If we agree on, then this SM input parameter page could be extended.

(Comments from Giampiero Passarino, February, 2010).


Red led QCD αs

Default αs values

NLO
  αs(MZ)
MSTW2008NLO 0.12018
NNPDF2.0 0.119
CTEQ6,6 0.118

MSTW
PDF αs(MZ) Λ(QCD)
MSTW2008LO 0.13939 0.254971
MSTW2008NLO 0.12018 0.255097
MSTW2008NNLO 0.11707 0.214634


Yellow led References

† C. Amsler et al. (Particle Data Group), Physics Letters B667 (2008) 1 and 2009 partial update for the 2010 edition.

-- ReiTanaka - 12-Feb-2010

>
>
"For estimates of PDF uncertainties, our recommendation would be for experimenters to use (at least) predictions from the three PDF fits that are truly global, i.e. that use results from the Tevatron and fixed target experiments as well as HERA: CTEQ, MSTW and NNPDF. The use of other PDFs for predictions is optional. The benchmarking exercises are useful to understand the αs dependence of LHC cross sections, and to understand what differences among the PDF groups result from assumptions of different values of αs. For the calculation of uncertainties at the LHC, the recommendation is to use the envelope provided by the central values and PDF+αs errors from the above three groups."
 
Added:
>
>

  -- ReiTanaka - 21-May-2010

Revision 12010-05-21 - ReiTanaka

Line: 1 to 1
Added:
>
>
META TOPICPARENT name="CrossSections"

Cross Section Calculation at 7 TeV

Help This is the standard recipe for Higgs cross section calculations for centre-of-mass energy of 7 TeV.

We had been asking the PDF4LHC working group to provide us a prescription on PDF sets, including - QCD alpha_s central value with the associated error to be used, - Definitions of PDF+alpha_s uncertainties and their treatments.

We got the following recommendation from PDF4LHC group on May 19, 2010 :

"For estimates of PDF uncertainties, our recommendation would be for experimenters to use (at least) predictions from the three PDF fits that are truly global, i.e. that use results from the Tevatron and fixed target experiments as well as HERA: CTEQ, MSTW and NNPDF. The use of other PDFs for predictions is optional. The benchmarking exercises are useful to understand the alpha_s dependence of LHC cross sections, and to understand what differences among the PDF groups result from assumptions of different values of alphas. For the calculation of uncertainties at the LHC, the recommendation is to use the envelope provided by the central values and PDF+alpha_s errors from the above three groups."

Since our next workshop at CERN (July 5-6) is approaching, we overall contacts want to ask each subgroup to start the corresponding calculations within the following scheme (we will put this recipe onto our TWiki page).

Aqua led Centre-of-mass Energy

  1. TeV

Complete inclusive cross sections at LO, NLO and NNLO(+NNLL)

Standard Model input parameter from

https://twiki.cern.ch/twiki/bin/view/LHCPhysics/SMInputParameter

Higgs mass range:

MH=[90GeV, 1TeV] or up to meaningful Higgs mass for each production process

Δ =5GeV for [90,200]GeV
step=10GeV for [200,300]GeV step=20GeV for [300,400]GeV step=50GeV for [400,1000]GeV

- QCD alpha_s: Use default values of each PDF set

- PDF sets: CTEQ6.6, MSTW2008, NNPDF2.0, HERAPDF1.0, ABKM09, GJR08

CTEQ, MSTW and NNPDF are the default sets for NLO calculations. Other, e.g. HERAPDF, ABKM and GJR are optional, but we recommend to calculate with these PDF sets as well. In particular, we need to compare MSTW with ABKM and GJR at NNLO. These sets are on LHAPDF.

- QCD scale uncertainty:

The factorization and the renormalization scales are process dependent and should be defined by each subgroup. The scale uncertainty should also be defined by each group, (e.g.. 1/2MH < mu_R, mu_F < 2MH, do 2D scan with 1/2 < mu_R/mu_F < 2)

- PDF, PDF+alpha_s uncertainties:

The PDF error with/without alpha_s error both at 68% and 90% C.L. should be calculated. If 68% C.L. calculation does not exist, we shall translate (e,g, by dividing 90%C.L. error by 1.64885).


The numbers are supposed to be the final one and ready for the next workshop at CERN. Once we complete these calculations and results are available, we shall discuss (e.g. before/at CERN) how to define the cross section central values and their associated errors.

e μ τ
0.510998910(13) MeV 105.658367(4) MeV 1776.84(17) MeV
u c t
190 MeV 1.40 GeV 172.5 +- 2.5 GeV
d s b
190 MeV 190 MeV 4.75 GeV

* Note: The charm and bottom masses are the pole masses used in the MSTW2008 PDF set.

Light quark masses

Light quark masses as used in parton show Monte Carlos are in some cases (e.g.HERWIG) effective masses used to regulate the parton shower in the infrared region (HERWIG also uses massive gluons), and as such may be treated more as a semi-perturbative QCD model parameter specific to a given generator rather than a SM parameter.

Charm and Bottom quark masses

We propose a process dependent choice of the quark masses since this issue cannot be generalized. The best choice should be given depending on the process. The current best fits for the MSbar masses are (arXiv:1001.5173),
MSbar mass mc(mc) mb(mb)
  1.28 GeV 4.16 GeV
These MSbar masses are obtained from fits to the QCD sum rules in charmonium and bottomonium systems and should normally be considered as the primary input. One could start from the MSbar values and compute the needed mass. The pole masses obtained from the values above strongly depend on the order of the calculation:
pole mass mc mb
1-loop 1.41 GeV 4.49 GeV
2-loop 1.55 GeV 4.69 GeV
On the other hand if we are going to use MSTW2008 PDFs, we are forced to use 4.75 GeV as the bottom pole mass. This should correspond to the 1-loop pole mass. Whatever we do, we are always forced to make a compromise due to consistency, i.e. to use mass values fitted at the order at which your observable is calculated and to be consistent with the input, in particular with the PDFs.

(Comments from Michael Spira, February, 2010).

Green led Gauge Boson Masses

W MW ΓW
  80.398(25) GeV 2.141(41) GeV
Z MZ ΓZ
  91.1876(21) GeV 2.4952(23) GeV


Orange led Electroweak Radiative Corrections

Gμ 1.16637(1)x10-5 GeV-2

For EW radiative corrections, it is more complicated than QCD because of renormalization and the treatment of unstable particles are complicated. For the treatment of resonances complex-mass scheme, fixed-width scheme and pole-mass scheme can be taken. Also for the renormalization scheme which defines relations between electroweak couplings and parameters beyond the leading order, various schemes exist such as α(0) scheme, α(MZ2) scheme and the GF scheme. For further detail, please refer to the Binoth Les Houches Accord arXiv:1001.1307, Section 5.1 - 5.3.. If we agree on, then this SM input parameter page could be extended.

(Comments from Giampiero Passarino, February, 2010).


Red led QCD αs

Default αs values

NLO
  αs(MZ)
MSTW2008NLO 0.12018
NNPDF2.0 0.119
CTEQ6,6 0.118

MSTW
PDF αs(MZ) Λ(QCD)
MSTW2008LO 0.13939 0.254971
MSTW2008NLO 0.12018 0.255097
MSTW2008NNLO 0.11707 0.214634


Yellow led References

† C. Amsler et al. (Particle Data Group), Physics Letters B667 (2008) 1 and 2009 partial update for the 2010 edition.

-- ReiTanaka - 12-Feb-2010

-- ReiTanaka - 21-May-2010

 
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