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arXiv · 1303.4974

Antenna Showers with One-Loop Matrix Elements

L. Hartgring·E. Laenen·P. Skands
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Abstract

We consider the probability for a colour-singlet qqbar pair to emit a gluon, in strongly and smoothly ordered antenna showers. We expand to second order in alphaS and compare to the second-order QCD matrix elements for Z -> 3 jets, neglecting terms suppressed by 1/NC^2. We give a prescription that corrects the shower to the matrix-element result at this order for both soft and hard emissions, thereby explicitly reducing its dependence on evolution- and renormalization-scale choices. We confirm that the choice of pT for both of these scales absorbs all logarithms through order alphaS^2, and contrast this with various alternatives. We include these corrections in the VINCIA shower generator and study the impact on LEP event-shape and fragmentation observables. An uncertainty estimate is provided for each event, in the form of a vector of alternative weights.

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L. Hartgring, E. Laenen, P. Skands. 2016-10-03. Antenna Showers with One-Loop Matrix Elements. https://doi.org/10.1007/jhep10(2013)127

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