Changes between Version 10 and Version 11 of dim6top
 Timestamp:
 10/14/19 10:55:40 (9 months ago)
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dim6top
v10 v11 48 48 49 49 ==== Note on NLO QCD 50 For NLO QCD simulation, the model authors recommend using the [wiki:SMEFTatNLO SMEFT@NLO] model which is mostly compatible with the baseline prescription of the LHC TOP WG. Few differences between the {{{dim6top}}}and [wiki:SMEFTatNLO SMEFT@NLO] (August 2019 version) models are to be noted:50 For NLO QCD simulation, the model authors recommend using the [wiki:SMEFTatNLO SMEFT@NLO] model which is mostly compatible with the baseline prescription of the LHC TOP WG. Few differences between the [wiki:dim6top dim6top] and [wiki:SMEFTatNLO SMEFT@NLO] (August 2019 version) models are to be noted: 51 51  [wiki:SMEFTatNLO SMEFT@NLO] includes Higgs and electroweak operators but does not include topquark FCNCs. 52 52  [wiki:SMEFTatNLO SMEFT@NLO] is moreover restricted to CPconserving operator coefficients. 53 53  [wiki:SMEFTatNLO SMEFT@NLO] imposes an enhanced U(2)q×U(2)u×U(3)d flavour symmetry in the quark sector, such that the righthanded bottom quark is treated on the same footing as other light downtype quarks. This is required for consistency with the fiveflavour scheme at NLO QCD, where {{{MB=0}}}. 54  [wiki:SMEFTatNLO SMEFT@NLO] normalizes the top dipole operator (with coefficient {{{ctG}}}) with a factor of the strong coupling constant {{{G}}} for compatibility with MG 2.x series at NLO in QCD. The 3.x series does not require sit. This implies that {{{ctG_dim6top = G * ctG_SMEFTatNLO}}}. Note that {{{G}}} runs.54  [wiki:SMEFTatNLO SMEFT@NLO] normalizes the top dipole operator (with coefficient {{{ctG}}}) with a factor of the strong coupling constant {{{G}}} for compatibility with MG 2.x series at NLO in QCD. The 3.x series does not require it. This implies that {{{ctG_dim6top = G * ctG_SMEFTatNLO}}}. Note that {{{G}}} runs. 55 55 56 Altogether, due to the enhanced quark flavour symmetry and to CPconservation, [ SMEFTatNLO] only includes a subset of 45 topquark operator coefficients:56 Altogether, due to the enhanced quark flavour symmetry and to CPconservation, [wiki:SMEFTatNLO SMEFT@NLO] only includes a subset of 45 topquark operator coefficients: 57 57 cQQ1, cQQ8, cQd1, cQd8, cQe1, cQe2, cQe3, cQl31, cQl32, cQl33, cQlM1, cQlM2, cQlM3, cQq11, cQq13, cQq81, cQq83, cQt1, cQt8, cQu1, cQu8, cblS3, cdp, cpQ3, cpQM, cpt, ctG, ctW, ctZ, ctd1, ctd8, cte1, cte2, cte3, ctl1, ctl2, ctl3, ctlS3, ctlT3, ctp, ctq1, ctq8, ctt1, ctu1, ctu8 58 58 and equates cQb1=cQd1, cQb8=cQd8, ctb1=ctd1, ctb8=ctd8. 59 59 60 A highprecision comparison with {{{dim6top}}} has been performed at leading order following the prescription of [https://arxiv.org/abs/1906.12310 1906.12310], with the [https://bazaar.launchpad.net/~rwgtdim6/mg5amcnlo/plugin_eft_contrib/revision/ plugin_eft_contrib] of MG.60 A highprecision comparison with [wiki:dim6top dim6top] has been performed at leading order following the prescription of [https://arxiv.org/abs/1906.12310 1906.12310], with the [https://bazaar.launchpad.net/~rwgtdim6/mg5amcnlo/plugin_eft_contrib/revision/ plugin_eft_contrib] of MG. More details are found in the arxiv note and in the {{{example}}} directory of the plugin. 61 61 62 62 The [wiki:SMEFTatNLO SMEFT@NLO] version dated from August 2019 does not include an implementation of fourfermion operators at NLO in QCD. Its validation is ongoing.