Description
String closepacking refers to the assumption that a system of multiple simultaneously fragmenting QCD strings can be described in terms of individual Lund strings fragmenting on an effective background created by other strings. The implementation of this idea in the Pythia event generator has had some success in describing observed strangeness-enhancement effects in high-multiplicity minimum-bias events at the LHC. However, the current model only accounts for string overlaps along the beam axis. We develop a formulation of string closepacking which is manifestly Lorentz covariant. This makes it applicable to strangeness-enhancement effects in $e^+e^- \to W^+W^- \to \mathrm{hadrons}$, and between "close" pairs of high-$p_\perp$ jets in hadron collisions, for the first time. We demonstrate the predictions of the model for these systems. We note that our model still averages over any dependence on (invariant) time, hence we do not expect it to yield fully realistic predictions for observables sensitive to such dependence.
| I am the presenting author | Yes |
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