Two-loop amplitudes for processes gg→Hg,qg→Hqg g \to H g, q g \to H q and qqˉ→Hgq \bar{q} \to H g at large Higgs transverse momentum

We compute the two-loop QCD corrections to amplitudes for processes $g g \to H g, q g \to H q$ and $q \bar{q} \to H g$ in the limit when the Higgs transverse momentum is larger than the top quark mass, $p_\perp \gg m_t$. These amplitudes are important ingredients for understanding higher-order QCD effects on Higgs transverse momentum distribution at large $p_\perp$.Comment: 22 pages, 4 figures, analytical results attached as ancillary file

Production of two Z-bosons in gluon fusion in the heavy top quark approximation

We compute QCD radiative corrections to the continuum production of a pair of Z-bosons in the annihilation of two gluons. We only consider the contribution of the top quark loops and we treat them assuming that $m_t$ is much larger than any other kinematic invariant in the problem. We estimate the QCD corrections to $pp \to ZZ$ using the first non-trivial term in the expansion in the inverse top quark mass and we compare them to QCD corrections of the signal process, $pp \to H \to ZZ$.Comment: 6 pages, 3 figure

W+3 jet production at the LHC as a signal or background

We discuss the production of W bosons in association with three jets at the LHC. We investigate how next-to-leading order QCD corrections modify basic kinematic distributions of jets and leptons. We also address the magnitude of NLO QCD effects in W+3 jet observables, relevant for SUSY searches at the LHC.Comment: 10 pages, 13 figures, OUTP-09-26-

On the light quark mass effects in Higgs boson production in gluon fusion

Production of Higgs bosons at the LHC is affected by the contribution of light quarks, that mediate the gg \to Hg transition. Although their impact is suppressed by small Yukawa couplings, it is enhanced by large logarithms of the ratio of the Higgs boson mass or its transverse momentum to light quark masses. We study the origin of this enhancement, focusing on the abelian corrections to gg \to Hg amplitudes of the form (C_F alphas L^{2})^n, where $L \in { ln(s/mb^2), ln(p_\perp^2/mb^2) }. We show how these non-Sudakov double logarithmic terms can be resummed to all orders in the strong coupling constant. Interestingly, we find that the transverse momentum dependence of these corrections is very weak due to a peculiar cancellation between different logarithmic terms. Although the abelian part of QCD corrections is not expected to be dominant, it can be used to estimate missing higher-order corrections to light quark contributions to Higgs boson production at the LHC.Comment: 18 pages, 2 figure