The Eötvös Paradox: The Enduring Significance of Eötvös' Most Famous Experiment
2020.01.16
Ephriam Fischbach, Department of Physics, Purdue University
Table of Contents available below.
Following the death of Baron Loránd von Eötvös in 1919, his collaborators Desiderius Pekar and Eugen Fekete co-authored a paper in 1922 containing the results of a series of earlier experiments testing the identity of inertial and gravitational mass, the Weak Equivalence Principle (WEP). Although the so-called "EPF" paper made no claim for any WEP violations, a subsequent 1986 reanalysis of the EPF paper revealed a pattern in their data suggesting the presence of a new 5th force in nature. Although the EPF data, and the 1986 reanalysis of these data, present fairly compelling evidence for such a 5th force, many contemporary experiments have failed to detect its presence. Here we summarize the key elements of this "Eötvös paradox," and suggest some possible paths to a resolution. Along the way we also discuss the close relationship between Eötvös and Einstein, and consider how their respective contributions may have been influenced by the other's. We conclude with a discussion of a possible connection between the recently detected "X17" particle and the 5th force.
Available on nanoHUB.org at: https://nanohub.org/resources/34059
Table of Contents:
00:00 The Eötvös Paradox: The Enduring Significance of Eötvös' Most Famous Experiment
03:05 Tests of the Equivalence Principle
05:07 The Search for New Macroscopic Forces: Pre-1986
06:31 The Search for New Macroscopic Forces: Pre-1986
06:42 The Search for New Macroscopic Forces: Pre-1986
06:51 Summary of Newtonian Gravity
08:27 New Yukawa Forces
09:21 The "Generic" Fifth Force Theory
10:19 Limits on Yukawa Forces: Pre-1986
12:22 Reanalysis of the Eötvös Experiment: 1986
12:44 Eötvös Results: Correlation with Baryon Number
15:03 The "Original" 5th Force
15:13 1986
17:41 Current Limits: Overview
18:12 Current Limits: Short Distances
19:14 The Eötvös Paradox
21:27 Evidence that the Eötvös Experiment was performed correctly
23:07 Evidence that the Eötvös Experiment was performed correctly
24:55 Untitled: Slide 19
25:57 Comparison of CuSO45H2O and Pt
30:09 Indications of New Physics in the Eötvös Experiment
34:25 And finally, the most compelling evidence that the Eötvös Experiment was performed correctly…
36:10 Evidence that the Eötvös Experiment was performed correctly
37:00 Experiments
37:07 Inverse-Square Law Tests: Airy Method (Stacey 1984)
37:38 Inverse-Square Law: Solar System Tests
39:48 Inverse-Square Law Tests: Spero 1980
40:39 Composition-Dependent Tests: (Thieberger 1987)
42:00 Composition-Dependent Tests: (Eöt-Wash, 1994)
42:54 Eöt-Wash Short-Distance Experiment
43:14 IUPUI Experiment (Decca, Lopéz, Fischbach, Krause)
44:11 New Limits on New Submicron Forces
45:01 Limits on Extra Dimensions and New Forces: Long-Range Composition-Dependent Limits
45:21 Towards a resolution of the Eötvös Paradox
49:23 Towards a resolution of the Eötvös Paradox: Experiments aren't all equal
50:29 Towards a resolution of the Eötvös Paradox: Some Possibilities
52:11 arXiv: 1910.10459
52:15 X17: Connection to the Original 5th Force?
52:53 The End