News & Events

HEPL / KIPAC Seminar

Wednesday, April 24, 2013

Robert D. Reasenberg

Smithsonian Astrophysical Observatory
Harvard-Smithsonian Center for Astrophysics

Testing the Weak Equivalence Principle on a Sounding Rocket

Abstract: I will describe SR-POEM, a Galilean test of the weak equivalence principle that is to be conducted during the free fall portion of the flight of a sounding rocket payload. The WEP is a key postulate of general relativity, but is violated in many theories that attempt to join gravity with the standard model of particle physics. This test of a single pair of substances will have a measurement uncertainty of σ(η) < 2 x 10 -17 after averaging the results of eight separate drops, each of 120 s duration.

The entire payload is inverted between successive drops to cancel potential sources of systematic error. The WEP measurement is made with a set of four of the SAO laser gauges, which have achieved an Allan deviation of 0.04 pm for an averaging time of 30 s. I will discuss aspects of the current design with an emphasis on those that bear on the accuracy of the determination of η. Among these is the as-yet unpublished redesigned test masses that are less susceptible to local gravitational perturbations. The discovery of a WEP violation (η ≠ 0) would have profound implications for physics, astrophysics and cosmology.


Time: 4:00pm – 5:15pm

Location: Physics/Astrophysics Bldg. Kistler Conference Rms. 102/103 (Map)

Light refreshments available 4:00pm; Presentation begiins 4:15pm

Open to All