Improving parameter estimation accuracy with torsion-bar antennas

TL;DR

This paper introduces a new triple-output torsion-bar antenna (TOBA) configuration for low-frequency gravitational wave detection, significantly enhancing polarization discrimination, detection rate, and parameter estimation accuracy.

Contribution

It proposes a novel triple-output TOBA design that incorporates vertical rotation measurements, enabling better polarization discrimination and improved detection capabilities.

Findings

Triple-output TOBA can discriminate two GW polarization modes.

Enhanced detection rate due to additional outputs.

Significant improvement in waveform parameter accuracy.

Abstract

We propose a new antenna configuration of a torsion-bar antenna (TOBA) and study its performance. A TOBA is a novel type of an antenna for low-frequency gravitational waves (GWs) which consists of two bar-shaped orthogonal test masses. Previously only the rotation of the bars on the horizontal plane had been considered as output signals. In this paper, we introduce a new antenna configuration for a TOBA to incorporate two additional outputs by measuring the rotation of the bars on the vertical planes. Such a triple-output TOBA can be regarded as a network of three coincident but misaligned interferometric detectors. We investigate its event detection rate and its parameter accuracies using Fisher analysis. We find that since the triple-output TOBA can discriminate two polarization modes of a short-duration GW signal even with a single antenna thanks to having three independent outputs, it improves the detection rate and the accuracies of waveform parameters drastically.