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From: scent@sask.UUCP (Scent Project)
Newsgroups: net.physics
Subject: Re: Re: Left, Right, Positive and Negative
Message-ID: <243@sask.UUCP>
Date: Sat, 15-Jun-85 23:48:41 EDT
Article-I.D.: sask.243
Posted: Sat Jun 15 23:48:41 1985
Date-Received: Mon, 17-Jun-85 04:11:16 EDT
References: <235@sask.UUCP> <129@bnl.UUCP>
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Organization: University of Saskatchewan, CANADA
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> > 
> > An interesting, related bit of trivia is the fact that "left" and
> > "right" are concepts which can only be communicated among two
> > parties if both parties can "see" each other.  
> 
...
> A physicist in a alien civilization could decide whether his/her/its
> world was made of matter or antimatter by looking at the decay of
> the long-lived neutron kaon.  The neutral K has semileptonic three
> body decay modes K -> e+ pi- nu, and K -> e- pi+ nu, with the ratio
> between the decay rates of 1.00648 +- 0.00035.  Thus, if the alien physicist
> observed a larger decay rate for the channel with the electron that
> has the same sign as the proton, he/she/it knows that the world is
> made of matter.  Determining left from right is a simple matter, after
						    ^^^^^^
> the sign of the proton charge is pinned down.  The spin of the neutrino
> is always pointing opposite to its direction of motion.  The convention
> of the direction of spin determines clockwise and counterclockwise,
> from which it is easy to figure out what left and right should be.
>  

Don' sound simple to me! [:-)]

					Ken McDonald