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To: "Gary L. Leung"
cc: murayama@hitoshi.lbl.gov
Subject: Re: Midterm problem
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In-reply-to: Your message of "Wed, 29 Oct 1997 16:12:23 PST."
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Date: Wed, 29 Oct 1997 16:33:29 -0800
From: Hitoshi Murayama
> I have difficult figuring out how to do problem 3c. As I know, each
>pion carries isospin I = 1. The question asks me to put together two
>pions with total isospin = 1 or 0. Is the problem asking for the THIRD
>component of the total I = 1 or 0?
No. For a two-pion state, one needs to specify both the total isospin I and
the relative angular momentum L. It turns out that not all combinations of I
and L are allowed; the Bose statistics of the pion requires that the
wavefunction does not change when you exchange two pions, and it leaves only
particular combinations of I and L allowed. You are asked to determine what
combinations are allowed, or in other words, what values of L are allowed for
I=0 and I=1.
> for 3b, I looked up the booklet and find out that the quark contents
>for p0 and pi0 are exactly the same. So why are they two different
>particles?
I assume "p0" you refer to is rho0, where rho is a Greek letter. They are different particles because they have different spin! rho0 has spin 1, pi0 has spin 0.
--
Hitoshi Murayama
Assistant Professor of Physics
University of California
Berkeley, CA 94720