LISA, binary stars, and the mass of the graviton

TL;DR

This paper evaluates how the LISA gravitational wave detector can improve bounds on the graviton mass by analyzing signals from binary star systems, potentially surpassing current Solar System limits.

Contribution

It provides improved estimates of LISA's capability to constrain the graviton mass using binary star observations, identifying promising systems for this purpose.

Findings

LISA could improve the graviton mass limit by up to 50 times over current bounds.

4U1820-30 is the best known binary for this measurement, potentially improving bounds 3-4 times.

Certain binaries like AM CVn could further enhance the limits by a factor of 10.

Abstract

We extend and improve earlier estimates of the ability of the proposed LISA (Laser Interferometer Space Antenna) gravitational wave detector to place upper bounds on the graviton mass, m_g, by comparing the arrival times of gravitational and electromagnetic signals from binary star systems. We show that the best possible limit on m_g obtainable this way is ~ 50 times better than the current limit set by Solar System measurements. Among currently known, well-understood binaries, 4U1820-30 is the best for this purpose; LISA observations of 4U1820-30 should yield a limit ~ 3-4 times better than the present Solar System bound. AM CVn-type binaries offer the prospect of improving the limit by a factor of 10, if such systems can be better understood by the time of the LISA mission. We briefly discuss the likelihood that radio and optical searches during the next decade will yield binaries that more closely approach the best possible case.