Testing for periodic changes in fundamental constants using long-term comparison of the SYRTE Cs fountains and H-masers

We analyze data sets from three separate Cs Fountains compared to various Hydrogen Masers to search for periodic changes correlated with the changing gravitational potential and boost with respect to the Cosmic Microwave Background. Data sets begin at a Modified Julian Day of 52822 (July 2nd 2003) and continue to November 2nd 2011. The main source of long-term noise in such experiments is the offsets associated with the various H-masers used in the comparison combined with the linear drift. The drift can vary to nearly immeasurable to as high as 1.3×10^-15 per day. To circumvent this problem we use the derivative technique. This technique significantly reduces the standard error when searching for periodic signals from such data. Results determine a standard error of the LPI coefficient of 4.8×10^-6, while boost sensitivity of fundamental constants was measured down to a precision in parts in 10^-11.