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From: ethan@utastro.UUCP (Ethan Vishniac)
Newsgroups: net.physics
Subject: Re: Do Positrons Have Negative Mass?
Message-ID: <607@utastro.UUCP>
Date: Mon, 26-Aug-85 10:40:33 EDT
Article-I.D.: utastro.607
Posted: Mon Aug 26 10:40:33 1985
Date-Received: Wed, 28-Aug-85 02:57:47 EDT
References: <437@ttidcb.UUCP> <1115@ihlpg.UUCP>
Organization: U. Texas, Astronomy, Austin, TX
Lines: 23

[]
> > In about 1966 I attended a seminar by Prof. Fairbanks who researched
> > at Stanford U (I think). He was trying to slow down positrons for long
> > enough to tell if they fell upwards or downwards.
> > 
> > Does anyone know how this turned out? If this experiment did not get
> > completed, has there been any other work?
> --------------------
> The existence of negative mass (i. e. mass that falls up) would blow
> general relativity out of the water as it violates the equivalence
> principle.  Also, the equivalence of gravitational and inertial mass
> has been shown experimentally to great accuracy (I can't remember the
> experimental error).  I don't know whether anyone has directly
> experimentally determined that positrons fall down,

I do (unfortunately I can't remember the reference but it was about
3-5 years ago).  Antimatter falls.
-- 
"Support the revolution        Ethan Vishniac
 in Latin America...           {charm,ut-sally,ut-ngp,noao}!utastro!ethan
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                               Department of Astronomy
                               University of Texas