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

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

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Chapter 7. Conclusions 169licly available, performs the NLO calcul<strong>at</strong>ion <strong>of</strong> cross-sections. The user can def<strong>in</strong>ecuts for the external particles as required. Us<strong>in</strong>g this program we performed somephenomenology relevant for the Tev<strong>at</strong>ron and the LHC. We observed th<strong>at</strong> whenexperimentalists choose exclusive f<strong>in</strong>al st<strong>at</strong>es <strong>with</strong> specific numbers <strong>of</strong> <strong>jets</strong>, such asCDF have done <strong>in</strong> their recent gg → H → WW ∗ studies . [215], one n<strong>at</strong>urallyencounters H + 2 <strong>jets</strong>. <strong>Higgs</strong> <strong>production</strong> through gluon fusion has been calcul<strong>at</strong>edthrough to NNLO [78,79,81], but when one explicitly selects <strong>two</strong> <strong>jets</strong> <strong>in</strong> the eventit is <strong>in</strong>appropri<strong>at</strong>e to use NNLO α S runn<strong>in</strong>g and PDF’s. R<strong>at</strong>her, one should m<strong>at</strong>chthese to the order <strong>in</strong> which the amplitude has been calcul<strong>at</strong>ed <strong>in</strong> perturb<strong>at</strong>ion theory.In our case this is NLO therefore, we were able to improve the LO scale uncerta<strong>in</strong>ty[214]. We also studied some phenomenology <strong>at</strong> the LHC. We compared the gluonandvector-<strong>boson</strong> fusion cross sections before and after VBF cuts f<strong>in</strong>d<strong>in</strong>g th<strong>at</strong> ther<strong>at</strong>io between the cross sections (after the cuts have been applied) shr<strong>in</strong>ks as thecentre <strong>of</strong> mass energy grows. We also studied the scale vari<strong>at</strong>ion and m<strong>in</strong>imum jetp T dependence <strong>at</strong> the LHC. F<strong>in</strong>ally we <strong>in</strong>vestig<strong>at</strong>ed the role <strong>of</strong> dynamic and fixedscales, f<strong>in</strong>d<strong>in</strong>g th<strong>at</strong> dynamic scales preserve the shape <strong>of</strong> lead<strong>in</strong>g order distributions.We observed, however, th<strong>at</strong> this preserv<strong>at</strong>ion <strong>in</strong> the high-p T region may actually beundesirable s<strong>in</strong>ce it is <strong>in</strong> this region th<strong>at</strong> the effective theory LO distributions showdevi<strong>at</strong>ions <strong>in</strong> shape due to top-mass effects.It is hoped th<strong>at</strong> the code will be <strong>of</strong> use to experimentalists as we enter an excit<strong>in</strong>gperiod <strong>in</strong> the hunt for the <strong>Higgs</strong>.

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