Combining states without scale hierarchies with ordered parton showers

Understand

We present a parameter-free scheme to combine fixed-order multi-jet results with parton-shower evolution.

• The scheme produces jet cross sections with leading-order accuracy in the complete phase space of multiple emissions, resumming large logarithms when appropriate, while not arbitrarily enforcing ordering on momentum configurations beyond the reach of the parton-shower evolution equation.
• This requires the development of a matrix-element correction scheme for complex phase-spaces including ordering conditions as well as a systematic scale-setting procedure for unordered phase-space points.
• The resulting algorithm does not require a merging-scale parameter.