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

1.5. Higgs plus two jets: Its phenomenological role and an overview ofthis thesis 29However, in addition to the weak process, a significant number of such eventsmay also be produced via the strong interaction. In order to accurately predictthe signal and, in particular, to simulate faithfully the expected significance in agiven Higgs model, a fully differential NLO calculation of QCD production of aHiggs and two hard jets is also required. The interference between the weak bosonfusion process and gluon fusion have been calculated and shown to be experimentallynegligible [102].In the Standard Model the Higgs couples to two gluons via a top-quark loop.Calculations which involve the full dependence on m t are difficult and a drasticsimplification can be achieved if one works in an effective theory in which the mass ofthe top quark is large [65,72,73]. For inclusive Higgs production this approximationis valid over a wide range of Higgs masses and, for processes with additional jets,the approximation is justified provided that the transverse momentum of each jetis smaller than m t [67]. Tree-level calculations have been performed in both thelarge-m t limit [64,103] and with the exact-m t [67] dependence.Results for the one-loop corrections to all of the Higgs + 4 parton processes havebeen published in 2005 [104]. Although analytic results were provided for the Higgs¯qq¯qq processes, the bulk of this calculation was performed using a semi-numericalmethod. In this approach the loop integrals were calculated analytically whereasthe coefficients with which they appear in the loop amplitudes were computed numericallyusing a recursive method. Although some phenomenology was performedusing this calculation [105], the implementation of fully analytic formulae will leadto a faster code and permit more extensive phenomenological investigations, whichis the main goal of this thesis.Since then there has been a drive to produce analytic results for the process,with the aim of improving the speed of the calculation. This thesis contains calculationsfor the most complicated helicity configurations; the φ-NMHV helicityconfigurations (both the pure gluon and qqgg cases), and the non-adjacent MHVhelicity gluon configuration. The remaining calculations have been performed elsewhere;the rational amplitudes (φ + + + +), (φ, − + ++) and (φ, qq + +) have