CMS pythia 8 colour reconnection tunes based on underlying-event data

Abstract

Abstract New sets of parameter tunes for two of the colour reconnection models, quantum chromodynamics-inspired and gluon-move, implemented in the pythia 8 event generator, are obtained based on the default CMS pythia 8 underlying-event tune, CP5. Measurements sensitive to the underlying event performed by the CMS experiment at centre-of-mass energies

$$\sqrt{s}=7$$

s

= 7

and 13

$$\,\text {Te\hspace{-.08em}V}$$

Te

V

, and by the CDF experiment at 1.96

$$\,\text {Te\hspace{-.08em}V}$$

Te

V

are used to constrain the parameters of colour reconnection models and multiple-parton interactions simultaneously. The new colour reconnection tunes are compared with various measurements at 1.96, 7, 8, and 13

$$\,\text {Te\hspace{-.08em}V}$$

Te

V

including measurements of the underlying-event, strange-particle multiplicities, jet substructure observables, jet shapes, and colour flow in top quark pair (

$${{\text {t}} {}{\bar{\text {t}}}}$$

t

t

¯

) events. The new tunes are also used to estimate the uncertainty related to colour reconnection modelling in the top quark mass measurement using the decay products of

$${{\text {t}} {}{\bar{\text {t}}}}$$

t

t

¯

events in the semileptonic channel at 13

$$\,\text {Te\hspace{-.08em}V}$$

Te

V

.