# Energy-conservation constraints on cosmic string loop production and distribution functions

## TL;DR

This paper examines energy conservation constraints on cosmic string loop production, showing that some recent models are incompatible with these limits, which impacts expected gravitational wave signals.

## Contribution

It introduces energy conservation constraints to cosmic string loop production models, ruling out certain recent proposals and refining predictions for gravitational wave signals.

## Key findings

- Some proposed loop production rates are ruled out by energy conservation.
- Certain models used in LIGO data analysis are incompatible with these constraints.
- Predicted gravitational wave signals based on these models are unlikely.

## Abstract

A network of cosmic strings would lead to gravitational waves which may be detected by pulsar timing or future interferometers. The details of the gravitational wave signal depend on the distribution of cosmic string loops, which are produced by intercommutations from the scaling network of long strings. We analyze the limits imposed by energy conservation, i.e., by the fact that the total amount of string flowing into loops cannot exceed the amount leaving the long strings. We show that some recent suggestions for the cosmic string loop production rate and distribution are ruled out by these limits. As a result, gravitational waves based on such suggestions, in particular "model 3" used in LIGO data analysis, are not to be expected.