## [1008.2561] Detecting massive gravitons using pulsar timing arrays

Authors: Kejia Lee, Fredrick A. Jenet, Richard H. Price, Norbert Wex, Michael Kramer

Date: 16 Aug 2010

Abstract: abbreviated:
Massive gravitons are features of some alternatives to general relativity. This has motivated experiments and observations that, so far, have been consistent with the zero mass graviton of general relativity, but further tests will be valuable. A basis for new tests may be the high sensitivity gravitational wave experiments that are now being performed, and the higher sensitivity experiments that are being planned. In these experiments it should be feasible to detect low levels of dispersion due to nonzero graviton mass. One of the most promising techniques for such a detection may be the pulsar timing program that is sensitive to nano-Hertz gravitational waves.
Here we present some details of such a detection scheme. The pulsar timing response to a gravitational wave background with the massive graviton is calculated, and the algorithm to detect the massive graviton is presented. We conclude that, with $90\%$ probability, massles gravitons can be distinguished from gravitons heavier than $3\times 10ˆ{-22}$\,eV (Compton wave length $\lambda_{\rm g}=4.1 \times 10ˆ{12}$ km), if biweekly observation of 60 pulsars are performed for 5 years with pulsar RMS timing accuracy of 100\,ns. If 60 pulsars are observed for 10 years with the same accuracy, the detectable graviton mass is reduced to $5\times 10ˆ{-23}$\,eV ($\lambda_{\rm g}=2.5 \times 10ˆ{13}$ km); for 5-year observations of 100 or 300 pulsars, the sensitivity is respectively $2.5\times 10ˆ{-22}$ ($\lambda_{\rm g}=5.0\times 10ˆ{12}$ km) and $10ˆ{-22}$ eV ($\lambda_{\rm g}=1.2\times 10ˆ{13}$ km). Finally, a 10-year observation of 300 pulsars with 100\,ns timing accuracy would probe graviton masses down to $3\times 10ˆ{-23}$\,eV ($\lambda_{\rm g}=4.1\times 10ˆ{13}$ km).

#### Aug 16, 2010

1008.2561 (/preprints)
2010-08-16, 18:43