Re: Neutrino & Anti-Neutrino

["Shapiro, Mark" <mshapiro@EXCHANGE.FULLERTON.EDU>]

John,

You raise a good point.  If the neutrino emitted in beta decay has mass (I
don't think there is any solid evidence that it does, but you can't prove a
negative) then the helicity would cease to be a convenient distinguishing
characteristic.  Instead you would have to look at the spin of each particle
relative to a preferred axis during the decay process to distinguish between
the two.  The anti-neutrino and neutrino would then exhibit different
"handedness".

Mark
http://www.IrascibleProfessor.com


-----Original Message-----
From: John Mallinckrodt [mailto:ajmallinckro@CSUPOMONA.EDU]
Sent: Wednesday, March 29, 2000 9:52 AM
To: PHYS-L@lists.nau.edu
Subject: Re: Neutrino & Anti-Neutrino


On Wed, 29 Mar 2000, Shapiro, Mark wrote:

> The difference between the neutrino and anti-neutrino is the "helicity",
> which is the projection of the particle spin on its direction of motion.
As
> I recall (I've got a 50-50 chance of being correct on this one), the
> neutrino has a left-handed helicity while the anti-neutrino has a
> right-handed helicity.

Hmm ...  If neutrinos have mass, does this mean that one person's neutrino
is another person's antineutrino and, therefore, that one person's beta-
decay is another person's beta+ decay?

John Mallinckrodt      mailto:ajm@csupomona.edu
Cal Poly Pomona          http://www.csupomona.edu/~ajm