4,927 research outputs found
Z+jet production at NNLO
We give a brief overview of our calculation of the next-to-next-to-leading
order (NNLO) QCD corrections to Z+jet production in hadronic collisions.
Phenomenological results are presented which comprise various differential
distributions for 8 TeV proton-proton collisions. A significant reduction of
the scale uncertainties is observed throughout as we move from NLO to NNLO. We
further discuss how this calculation can be used to describe the inclusive
Z-boson production at large transverse momentum. To this end, the theory
prediction is compared to the measurements performed by the ATLAS and CMS
collaborations at a centre-of-mass energy of 8 TeV. Here, the inclusion of NNLO
QCD effects are found to result in a substantial improvement in the agreement
between theory and data for the normalised distributions.Comment: 8 pages, 5 figures, to appear in the proceedings of Loops and Legs in
Quantum Field Theory, 24-29 April 2016, Leipzig, German
The colourful antenna subtraction method
We present a general subtraction scheme for NNLO calculations in massless
QCD: the \textit{colourful antenna subtraction method}. It is a reformulation
of the antenna subtraction approach designed to address some of the limitations
of the traditional framework, especially aiming at high-multiplicity processes.
In the context of the new formalism, structures needed to locally subtract the
infrared-divergent behaviour of real emission corrections are systematically
inferred from virtual subtraction terms, relying on the cancellation of
infrared singularities and on the correspondence between integrated and
unintegrated antenna functions. We illustrate in detail how the colourful
antenna subtraction method works up to NNLO. The algorithm is particularly
suited to be fully automated for the generation of NNLO subtraction terms for
generic processes. We employ the new formalism to assemble the subtraction
terms required for the calculation of the NNLO correction to hadronic three-jet
production and describe their validation procedure
The colourful antenna subtraction method
We present a general subtraction scheme for NNLO calculations in massless QCD: the colourful antenna subtraction method. It is a reformulation of the antenna subtraction approach designed to address some of the limitations of the traditional framework, especially aiming at high-multiplicity processes. In the context of the new formalism, structures needed to locally subtract the infrared-divergent behaviour of real emission corrections are systematically inferred from virtual subtraction terms, relying on the cancellation of infrared singularities and on the correspondence between integrated and unintegrated antenna functions. We illustrate in detail how the colourful antenna subtraction method works up to NNLO. The algorithm is particularly suited to be fully automated for the generation of NNLO subtraction terms for generic processes. We employ the new formalism to assemble the subtraction terms required for the calculation of the NNLO correction to hadronic three-jet production and describe their validation procedure
Global Optimization by Energy Landscape Paving
We introduce a novel heuristic global optimization method, energy landscape
paving (ELP), which combines core ideas from energy surface deformation and
tabu search. In appropriate limits, ELP reduces to existing techniques. The
approach is very general and flexible and is illustrated here on two protein
folding problems. For these examples, the technique gives faster convergence to
the global minimum than previous approaches.Comment: to appear in Phys. Rev. Lett. (2002
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