Measurement of four-jet production in the ATLAS experiment*

Measurements of multi-jet cross section ratios are presented.

The measured quantities are the ratio of the four-jet and three-jet

cross sections and the ratio of the four-jet and two-jet cross sections.

The data were collected with the ATLAS detector in proton-proton

collisions at a center of mass energy of 13 TeV during 2015-2018.

The results are presented as a function of the transverse jet momentum.

Predictions from different Monte Carlo event generators are compared

to the data.