We consider QCD corrections to Higgs boson production through gluon-gluon fusion in hadron collisions. Using the recently evaluated [14] two-loop amplitude for this process and the corresponding factorization formulae [15]-[18] describing soft-gluon bremsstrahlung at O(α 2 S ), we compute the soft and virtual contributions to the next-to-next-to-leading order cross section. We also discuss soft-gluon resummation at next-to-next-to-leading logarithmic accuracy. Numerical results for Higgs boson production at the LHC are presented. ‡ Partially supported by Fundación Antorchas JHEP05(2001)025exceeds all the other production channels by a factor decreasing from 8 to 5 when M H increases from 100 to 200 GeV. When M H approaches 1 TeV, gg fusion still provides about 50% of the total production cross section.QCD radiative corrections at next-to-leading order (NLO) to gg-fusion were computed and found to be large [10]- [12]. Since approximate evaluations [13] of higher-order terms suggest that their effect can still be sizeable, the evaluation of the next-to-next-to-leading order (NNLO) corrections is highly desirable.In this paper, we perform a first step towards the complete NNLO calculation. We use the recently evaluated [14] two-loop amplitude for the process gg → H and the soft-gluon factorization formulae [15]-[18] for the bremsstrahlung subprocesses gg → Hg and gg → Hgg, Hqq, and we compute the soft and virtual contributions to the NNLO partonic cross section. We also discuss all-order resummation of soft-gluon contributions to next-to-next-to-leading logarithmic (NNLL) accuracy.We use the approximation M t M H , where M t is the mass of the top quark. The results of the NLO calculation in ref. [12] show that this is a good numerical approximation [13] of the full NLO correction, provided the exact dependence on M H /M t is included in the leading-order (LO) term. We can thus assume that the limit M t M H continues to be a good numerical approximation at NNLO. The hadronic cross section for Higgs boson production is obtained by convoluting the perturbative partonic cross sections with the parton distributions of the colliding hadrons. Besides the partonic cross sections, the other key ingredients of the NNLO calculation are the NNLO parton distributions. Even though their NNLO evolution kernels are not fully available, some of their Mellin moments have been computed [19] and, from these, approximated kernels have been constructed [20]. Recently, the new MRST [21] sets of distributions became available 1 , including the (approximated) NNLO densities, which allows an evaluation of the hadronic cross section to (almost full) NNLO accuracy.We use our NNLO result for the partonic cross sections and the MRST parton distributions at NNLO to compute the Higgs boson production cross section at the LHC. In this paper, we do not present numerical results for Run II at the Tevatron. Inclusive production of Higgs boson through gluon-gluon fusion is phenomenologically less relevant at the Tevatron: it is not regarded as a main ...

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Barrier coating materials used in plasma display panel (PDP) cells strongly affect the discharge voltages. Although magnesium oxide (MgO) is widely used for barrier coating in the current generation of commercial PDP cells, other alkaline earth oxides have been studied as alternatives and indeed some of them are now known to have lower discharge breakdown voltages for PDP cells, which would increase the energy efficiency of the cells. On the other hand, the resistance against physical sputtering is another critical parameter for barrier coating. In this work, sputtering yields of CaO, SrO and BaO by monochromatic Ne or Xe ion beams are obtained experimentally as functions of beam energy in the range 100–300 eV. Despite the large differences in mass among the targets and incident ions, sputtering yields are found to be similar in magnitude among them for a given incident energy.

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Sputtering yields of gold (Au) by noble gas (He, Ne, Ar, Kr or Xe) ions have been measured in the low injection energy range 25–200 eV. The yield data presented here were obtained from mass-selected ion beam sputtering experiments, in which the ion beam has a very narrow energy spread and contains no impurity ions. The newly obtained yield data set, together with the fitting functions for the yield dependence on the injection energy, provide an accurate and reliable database for the study of fundamental physical mechanisms of sputtering phenomena at low energies, where experimental data had been scarce.