Result of the MICROSCOPE weak equivalence principle test

Abstract

The space mission MICROSCOPE dedicated to the test of the equivalence principle (EP) operated from April 25, 2016 until the deactivation of the satellite on October 16, 2018. In this analysis we compare the free-fall accelerations (a A and a B) of two test masses in terms of the Eötvös parameter η ( A,B ) = 2 a A − a B a A + a B . No EP violation has been detected for two test masses, made from platinum and titanium alloys, in a sequence of 19 segments lasting from 13 to 198 h down to the limit of the statistical error which is smaller than 10−14 for η(Ti, Pt). Accumulating data from all segments leads to η(Ti, Pt) = [−1.5 ± 2.3 (stat) ± 1.5 (syst)] × 10−15 showing no EP violation at the level of 2.7 × 10−15 if we combine stochastic and systematic errors quadratically. This represents an improvement of almost two orders of magnitude with respect to the previous best such test performed by the Eöt-Wash group. The reliability of this limit has been verified by comparing the free falls of two test masses of the same composition (platinum) leading to a null Eötvös parameter with a statistical uncertainty of 1.1 × 10−15.

MICROSCOPE mission: statistics and impact of glitches on the test of the weak equivalence principle *

“…One in particular (session 380-see reference [20] for a list of sessions) yields a 7σ detection on the reference instrument (the test masses of which are made of the same material [2]). This detection hints towards a systematic effect unaccounted for and made apparent by the lower-than-average noise level of that particular session [28]. Additionally, a forest of strong lines can be seen in the differential acceleration measured for this session (black line of figure 10).…”

“…A standard analysis of some measurement sessions provides a statistically unlikely (given the estimates of the Eötvös parameter on other MICROSCOPE measurement sessions [28]) level of a WEP violation. One in particular (session 380-see reference [20] for a list of sessions) yields a 7σ detection on the reference instrument (the test masses of which are made of the same material [2]).…”

Galaxy rotation curve in hyperconical universes: a natural relativistic MOND

“…GR (see table 1 for a list of abbreviations and acronyms) has been validated at least for local scales, such as the Solar System, among others [1,2]. To reach this, parameterized post-Newtonian (PPN) techniques and the weak equivalence principle (WEP, equalizing the inertial and gravitational masses) are usually considered [3,4].…”

Solving nonlinear Klein-Gordon equations on unbounded domains via the Finite Element Method

“…Our Python software is coded in an object-oriented fashion and builds upon an existing Python FEM package -Sfepy [30], which was early identified as a flexible open-source FEM library in Python. This code is being actively developed on GitHub 3 .…”

“…General Relativity (GR) is our best understanding of gravity. It passes all the tests thrown at it so far [1], including the most recent test of the weak equivalence principle -the MICROSCOPE experiment [2,3]. However, gravity cannot go but hand in hand with cosmology, a discipline that relates to many questions in fundamental physics.…”