Gluon fusion into Higgs pairs at NLO QCD and the top mass scheme.

We present the calculation of the full next-to-leading order (NLO) QCD corrections to Higgs boson pair production via gluon fusion at the LHC, including the exact top-mass dependence in the two-loop virtual and one-loop real corrections. This is the first independent cross-check of the NLO QCD corrections presented in the literature before. Our calculation relies on numerical integrations of Feynman integrals, stabilised with integration-by-parts and a Richardson extrapolation to the narrow width approximation. We present results for the total cross section as well as for the invariant Higgs-pair-mass distribution at the LHC, including for the first time a study of the uncertainty due to the scheme and scale choice for the top mass in the loops.

W + W - H production at lepton colliders: a new hope for heavy neutral leptons.

We present the first study of the production of a Standard Model Higgs boson at a lepton collider in association with a pair of W bosons, e + e - → W + W - H , in the inverse seesaw model. Taking into account all relevant experimental and theoretical constraints, we find sizable effects due to the additional heavy neutrinos up to - 38 % on the total cross-section at a center-of-mass energy of 3 TeV, and even up to - 66 % with suitable cuts. This motivates a detailed sensitivity analysis of the process e + e - → W + W - H as it could provide a new, very competitive experimental probe of low-scale neutrino mass models.

Thermochemical properties of the gaseous bromo-iodides of Dy and of the Na-Dy tetrahalo complexes.

The gaseous mixed dimers NaDyBr4 and NaDyI4 and the bromo-iodide species DyBrI, DyBr2I, DyBrI2, NaDyBr3I, NaDyBr2I2, and NaDyBrI3 were generated in an effusion cell reactor at elevated temperatures using several different source configurations and were identified by mass spectrometry. A number of gaseous equilibria involving these species were studied, and thermochemical properties were derived with the aid of thermal functions based on estimated molecular constants. Enthalpies of formation of NaDyBr4 and NaDyI4 are compared with values in the literature, while results for the bromo-iodides are in close accord with values interpolated from data on the pure metal bromides and iodides.