Re: What is this "internal clock" in muon which slows down its rate of decay when they move very fast?

From: PD (pdraper_at_yahoo.com)
Date: 01/29/05 

Date: 29 Jan 2005 08:36:09 -0800

Michael Levin wrote:
> Sorry if this is a stupid question - I'm a biologist with an amateur
> interest in physics. I was listening to an audio lecture by Richard
Wolfson
> and he was talking about the experiment where, due to relativistic
effects,
> the lifetime of muons is extended due to their rapid motion (0.9c or
> something like that) and the resulting time dilation. He was making
the
> point that it isn't just clocks that are affected by time dilation,
but
> everything (time itself). I think I follow all this stuff so far. But
he
> keeps talking about "the muon's internal clock". I am sure this must
be a
> euphemism for something, but what? What's this internal clock? Does
a muon
> have internal components of some sort which decide when it's to
decay? It
> would seem that the relativistic explanation for what's going on
models the
> muon as a physical clock-like process (which can be slowed). But,
what is
> the relationship between quantum mechanics' assertion that decay is
in
> principle unpredictable (presumably meaning, not controlled by
mechanistic
> factors) and this effect where it would seem that some process counts
time
> for the muon? I hope my question makes sense; I'd like to know if
anything
> is known about how these two theories intersect in this case. Does
the muon
> have internal components which decide when to decay? If so, is it
different
> from "point" particles like electrons (and if yes, can the same sort
of
> relativistic experiment be done with them)? Any thoughts would be
> appreciated!
>
> --
>
> Mike Levin
> mlevin77@comcast.net

Simply addressing the point as to whether the time dilation is real (as
viewed in a frame where the particle is moving), note that g-2
experiments store muons in storage rings (where they precess). Thus,
both the speed of the muons is known (the muon bunches would proceed
from station to station on the ring at a rate that is measurable), and
the lifetime in the laboratory is known (by the decay rate from the
population dN/dt). Thus the time dilation in this case is NOT simply
inferred by the distance traveled.

PD

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