Talk abstract details

The paper reports the advances in the development of an experiment (TEPEE/GReAT) to test the Equivalence Principle (EP) at a level of accuracy equal to 5e-15, by means of a differential accelerometer free falling in a cryogenic vacuum capsule released from a stratospheric balloon. Such an accuracy requires resolving a very small signal out of the instrument's intrinsic noise and the noise associated with the instrument's motion. Imperfections in the construction of the detector introduce gravity gradient noise that it is possible to separate from the violation signal spinning the detector around an horizontal axis in order to have the EP violation signal and the gravity gradients one modulated at two different frequencies.
The paper shows:
i) Various configurations of the differential detector, able to provide remarkable separation between the effects of motion and gravity gradients and the EP violation signal;
ii) The latest advances in the development of the detector in terms of electronic set-up to reach the maximum common mode rejection;
iii) The experimental results on prototype instruments showing high sensitivity and common mode rejection factor.