# Evolution of Semilocal String Networks: II. Velocity estimators

## TL;DR

This paper presents a detailed numerical analysis of semilocal string networks, introducing a new core detection algorithm that improves length and velocity measurements, confirming a linear scaling regime and analyzing segment distributions.

## Contribution

It introduces a novel core detection algorithm for semilocal strings, enabling precise measurement of individual segment properties and their evolution.

## Key findings

- Confirmed linear scaling regime for string networks.
- New detection algorithm yields higher length estimates.
- No correlation between segment length and velocity.

## Abstract

We continue a comprehensive numerical study of semilocal string networks and their cosmological evolution. These can be thought of as hybrid networks comprised of (non-topological) string segments, whose core structure is similar to that of Abelian Higgs vortices, and whose ends have long--range interactions and behaviour similar to that of global monopoles. Our study provides further evidence of a linear scaling regime, already reported in previous studies, for the typical length scale and velocity of the network. We introduce a new algorithm to identify the position of the segment cores. This allows us to determine the length and velocity of each individual segment and follow their evolution in time. We study the statistical distribution of segment lengths and velocities for radiation- and matter-dominated evolution in the regime where the strings are stable. Our segment detection algorithm gives higher length values than previous studies based on indirect detection methods. The statistical distribution shows no evidence of (anti)correlation between the speed and the length of the segments.