AbstractThis paper presents new sets of parameters (“tunes”) for the underlying-event model of the $${\textsc {herwig}} \,7$$
H
E
R
W
I
G
7
event generator. These parameters control the description of multiple-parton interactions (MPI) and colour reconnection in $${\textsc {herwig}} \,7$$
H
E
R
W
I
G
7
, and are obtained from a fit to minimum-bias data collected by the CMS experiment at $$\sqrt{s}=0.9$$
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=
0.9
, 7, and $$13 \,\text {Te}\text {V} $$
13
Te
. The tunes are based on the NNPDF 3.1 next-to-next-to-leading-order parton distribution function (PDF) set for the parton shower, and either a leading-order or next-to-next-to-leading-order PDF set for the simulation of MPI and the beam remnants. Predictions utilizing the tunes are produced for event shape observables in electron-positron collisions, and for minimum-bias, inclusive jet, top quark pair, and Z and W boson events in proton-proton collisions, and are compared with data. Each of the new tunes describes the data at a reasonable level, and the tunes using a leading-order PDF for the simulation of MPI provide the best description of the data.
Recent CMS results on soft and small-x QCD physics
