Hadronic production of a Higgs boson in association with two jets at ...

6.6. Summary 164at LO and the effective theory result at NLO are both in MCFM). The resultsare plotted in Fig. 6.10, we have chosen the same jet cuts and √ s as the previoussection. We have calculated the distributions for µ = H T and µ = m H at NLOin the effective theory (m t → ∞) and the LO result for the full (m t dependent)theory. It is clear that the shape of the top-mass dependent LO result is moreclosely matched by the fixed order prediction. This is because both the top-masseffects and the fixed scale choice tend to reduce the number of high-p T jets, whilstthe dynamic scale increases them. Therefore, although there may be good physicsreasons to motivate using a dynamic scale in general calculations, for calculationsinvolving the Higgs effective theory the major differences between fixed scales anddynamic ones occur in the high-p T regions. These regions are exactly those in whichwe expect the LO result to incorrectly predict the shape of distributions. Using adynamic scale maintains this shape, whereas using a fixed scale has the effect ofmore closely matching top-mass effects by producing a softer spectrum.6.6 SummaryIn this chapter we have presented phenomenological predictions for the production ofa Higgs boson and two jets through gluon fusion. These predictions have been madepossible through the implementation of compact analytic results for the relevant1-loop amplitudes (the most complicated being calculated in Chapters 3,4 and 5)[106–109,206,208,212]. The speed with which these amplitudes can be evaluatedhas enabled us to improve upon an existing semi-numerical implementation of thesame process [105], with various decays of the Higgs boson now included.We have investigated the behaviour of the NLO cross section at the Tevatron,where contributions from this channel form part of the event sample for the latestHiggs searches [217]. We find that corrections to the event rate in the Higgs + ≥2 jet bin are modest and that the estimate of the theoretical error is reduced byapproximately a factor of two compared to a LO calculation. The resulting error isstill rather large, corresponding to approximately +40% and −30% across the region