What is this equation?

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Edward Green - 23 Jul 2008 02:11 GMT

In the student preface to the prepublication copy of Mark Srednicki's
Quantum Field Theory there is a list of equations serving as kind of a
pop quiz whether you a ready to study QFT. I at least have clue about
all of them except what I will render as:

d(sigma)/d(omega) = | f(theta,phi) | ^2

I'll take a wild stab, and say it is the differential of scattering
cross section with solid angle.

About right? What specifically is f( ) ?

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Eric Gisse - 23 Jul 2008 03:12 GMT

> In the student preface to the prepublication copy of Mark Srednicki's
> Quantum Field Theory there is a list of equations serving as kind of a
[quoted text clipped - 7 lines]
>
> About right? What specifically is f( ) ?

Needs more context. The scattering formula has a different form.

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Edward Green - 23 Jul 2008 03:50 GMT

> > In the student preface to the prepublication copy of Mark Srednicki's
> > Quantum Field Theory there is a list of equations serving as kind of a
[quoted text clipped - 9 lines]
>
> Needs more context. The scattering formula has a different form.

Heh. There was no more context! This was a recognition quiz.

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PD - 23 Jul 2008 03:41 GMT

Well, it's *about* right, but the formula above looks odd to me. I
would have said that f(theta, phi) is the scattering amplitude, but
the differential cross-section is missing a final-state density. Then
the equation would be called the Fermi Golden Rule.

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Natural Science Forum / Physics / General Physics / July 2008

What is this equation?