New Graviton Mass Bound from Binary Pulsars. (arXiv:2007.04531v1 [gr-qc])

<a href="http://arxiv.org/find/gr-qc/1/au:+Shao_L/0/1/0/all/0/1">Lijing Shao</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Wex_N/0/1/0/all/0/1">Norbert Wex</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Zhou_S/0/1/0/all/0/1">Shuang-Yong Zhou</a>

In Einstein’s general relativity, gravity is mediated by a massless metric

field. The extension of general relativity to consistently include a mass for

the graviton has profound implications for gravitation and cosmology. Salient

features of various massive gravity theories can be captured by Galileon

models, the simplest of which is the cubic Galileon. The presence of the

Galileon field leads to additional gravitational radiation in binary pulsars

where the Vainshtein mechanism is less suppressed than its fifth-force

counterpart, which deserves a detailed confrontation with observations. We

prudently choose fourteen well-timed binary pulsars, and from their intrinsic

orbital decay rates we put a new bound on the graviton mass, $m_g lesssim 2

times 10^{-28},{rm eV}/c^2$ at the 95% confidence level, assuming a flat

prior on $ln m_g$. It is equivalent to a bound on the graviton Compton

wavelength $lambda_g gtrsim 7 times 10^{21},{rm m}$. Furthermore, we

extensively simulate times of arrival for pulsars in orbit around stellar-mass

black holes and the supermassive black hole at the Galactic center, and

investigate their prospects in probing the cubic Galileon theory in the near

future.

In Einstein’s general relativity, gravity is mediated by a massless metric

field. The extension of general relativity to consistently include a mass for

the graviton has profound implications for gravitation and cosmology. Salient

features of various massive gravity theories can be captured by Galileon

models, the simplest of which is the cubic Galileon. The presence of the

Galileon field leads to additional gravitational radiation in binary pulsars

where the Vainshtein mechanism is less suppressed than its fifth-force

counterpart, which deserves a detailed confrontation with observations. We

prudently choose fourteen well-timed binary pulsars, and from their intrinsic

orbital decay rates we put a new bound on the graviton mass, $m_g lesssim 2

times 10^{-28},{rm eV}/c^2$ at the 95% confidence level, assuming a flat

prior on $ln m_g$. It is equivalent to a bound on the graviton Compton

wavelength $lambda_g gtrsim 7 times 10^{21},{rm m}$. Furthermore, we

extensively simulate times of arrival for pulsars in orbit around stellar-mass

black holes and the supermassive black hole at the Galactic center, and

investigate their prospects in probing the cubic Galileon theory in the near

future.

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