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Forum: Physics List
Re: Question BERT vs. BIC physics lists (Dipak Rimal)
Date: 19 Nov, 2014
From: Tom Roberts <Tom Roberts>

On Wed, 19 Nov 2014 07:00:05 GMT, Dipak Rimal wrote:
> I also have a question about pi^-/mu^- capture at rest process. In our
> simulation, almost all of the produced pi^-/mu^- are being captured,
> none of them decay (at rest), less than 0.5 % decay in flight. This
> sounds a bit odd to me. Any comments?

If your target is large enough that most pi- and mu- stop, then this makes sense. Almost all negative particles that stop in a material get captured very quickly (few femtoseconds IIRC), especially for high-Z materials. Speaking loosely, that's because inside each atom the electrons do not fully screen the nuclear charge, so there is a strong E field that captures negative particles with low enough kinetic energy. While stopping, every particle will have low enough KE to be captured, so inside a material the only decays in flight of negative particles are those that decay before they stop.

Note also that once captured, the negative muon has effectively a shorter decay lifetime than a free muon. This is a function of the Z of the nucleus, and can be a large factor for high-Z nuclei like Hg.

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1 None: Re: BERT vs. BIC physics lists   (Dipak Rimal - 24 Nov, 2014)
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