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Higgs+jets : data vs theory

Higgs+jets : data vs theory. Joey Huston Bruce Mellado. 1. Higgs(-> gg )+jets. Most of the excess observed for Higgs production is in >=1 jet final states Maybe CMS does not see as large of an excess

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Higgs+jets : data vs theory

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  1. Higgs+jets: data vs theory Joey Huston Bruce Mellado 1

  2. Higgs(->gg)+jets • Most of the excess observed for Higgs production is in >=1 jet final states • Maybe CMS does not see as large of an excess • In any case, we would like to use the best theory we can to understand the level of excess • For inclusive Higgs production through gg fusion, we use a NNLO+NNLL calculation • which means a NLO calculation for Higgs + 1 jet • and a LO calculation for Higgs + 2 jets 2

  3. NNNLO inclusive • gg->Higgs cross section is not very convergent • So it’s appropriate to think about effects of still higher order corrections • Approximate NNNLO corrections have been carried out resumming the effects of soft gluon radiation; recently BFKL logs have been resummed as well, leading to more scale stability and an additional increase in the cross section This increase should be passed on to the 1 and 2 jet cross sections as well 3

  4. Higgs+1 jet at NLO • …from Dec. 20 meeting • NLO cross section has a LO-like scale dependence 4

  5. Higgs+1 jet at NNLO • So the NNLO correction for Higgs+1 jet (through gg fusion) is about 30% • gg corresponds to about 65% of the cross section; they are working on other initial states and it is probable that the NNLO corrections for the other initial states (gq) will be somewhat smaller (maybe 1.15 instead of 1.30) arXiv:1302.6216 σNLO/σLO = 1.6 σNNLO/σNLO = 1.3 5

  6. Higgs+jets(binned cross sections) Xiaohui Liu resummation for Higgs + 0 jet and for Higgs + 1 jet has lead to sizeable reduction in scale uncertainty for exclusive Higgs +0,1 jet production we need to revisit the formulation of the uncertainties for binned jet Higgs cross sections this is a task for Snowmass/ Les Houches also investigate jet veto effects for higher energy accelerators

  7. What about Higgs+>=2 jet final states? • We know Higgs+2 jets to NLO • A NNLO calculation of Higgs+2 jets is a long way off, but by general arguments we might expect the size of the NNLO corrections to be <= that seen for Higgs+1 jet 7

  8. Sherpa+… • One of the best vehicles to estimate contributions to the different jet multiplicities may be Sherpa(+gosam/MCFM/blackhat) • At least it’s the one I’m currently using • One can include Higgs+0,1 and 2 jets at NLO, up to 3 additional jets at LO, with extra jets from parton showers, looking at the effects of varying the merging scale, the renormalization scale, the factorization scale and the resummation scale • with maybe some motivated re-weighting based on the new theory predictions • I have Higgs+1 jet (at NLO) working now, and should have Higgs+2 jets in the next few days • The same thing can be done for W+jets, so this may be a useful cross-check in a channel where the statistics are much higher and the physics perhaps better understood • We know we see an excess • It may be a fluctuation, we would like to understand the theory predictions and their uncertainties. 2nd jet receives substantial contributions from 3-jet matrix element 8

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