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Standard Model Input Parameters at LHCThese are the Standard Model input parameters agreed among ATLAS, CMS, LHCb and theory community for Higgs cross section calculations. The same parameters can be used for other SM and BSM processes at LHC. 
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Standard Model Input Parameters at LHC 
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Standard Model Input Parameters at LHCThese are the Standard Model input parameters agreed among ATLAS, CMS, LHCb and theory community for Higgs cross section calculations. The same parameters can be used for other SM and BSM processes at LHC. 
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Standard Model Input Parameters at LHCThese are the Standard Model input parameters agreed among ATLAS, CMS, LHCb and theory community for Higgs cross section calculations. The same parameters can be used for other SM and BSM processes at LHC.
Lepton&Quark Masses ^{†}
* Note: The charm and bottom masses are the pole masses used in the MSTW2008 PDF set.
Light quark massesLight 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 semiperturbative QCD model parameter specific to a given generator rather than a SM parameter.
Charm and Bottom quark massesWe 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),
(Comments from Michael Spira, February, 2010).
Gauge Boson Masses ^{†}
Electroweak Radiative Corrections
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 complexmass scheme, fixedwidth scheme and polemass 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(M_{Z}^{2}) scheme and the G_{F} 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).
QCD α_{s}
PDF4LHC recipeWe shall follow up the discussion at PDF4LHC working group for the consensus on an agreed value of QCD α_{s} and procedure for associated error treatment.The current agreement is to produce in the very short run some benchmarks for standard candles (typically, W, Z, Higgs and top cross sections) using different sets of PDFs, and both each group's favorite prescription, but also some common agreed prescription for:
(Comments from Albert De Roeck, February 18, 2010).
TEMPORARY recipeIn the mean time, we want to start the calculations for the Freiburg Workshop. Here is the TEMPORARY recipe suggested by Stefano Forte while we wait for the official recommendation by PDF4LHC group.
When doing an NNLO computation, I suggest to first do the NLO computation according to the above recipe. Then do both NLO and NNLO using MSTW2008 with the corresponding recommended values of α_{s}. If it turns out that the PDF uncertainty on the NLO computation obtained from the recipe is much larger than the NLONNLO difference, consider the small NNLO uncertainty with due skepticism. (Comments from Stefano Forte, February 19, 2010).
Default α_{s} valuesNLO
MSTW
References† C. Amsler et al. (Particle Data Group), Physics Letters B667 (2008) 1 and 2009 partial update for the 2010 edition.
 ReiTanaka  20May2010 