All Questions
5
questions
1
vote
0
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52
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Colour Factor in QCD Pair Annihilation
My question occurred when I was reading Introduction to Elementary Particles by David J. Griffiths. In chapter 8, part 8.5, he is calculating the colour factor of quark-antiquark annihilation.
My ...
- 81
0
votes
1
answer
89
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Color factor in Breit-Wigner formula
We are given the Breit-Wigner formula for the process $ud\rightarrow W\rightarrow e\nu$ as $$\sigma=\frac{1}{N_c^2}\frac{2J_W+1}{(2J_u+1)(2J_d+1)}\frac{4\pi}{s}\frac{\Gamma_{ud}\Gamma_{e\nu}}{(\sqrt{s}...
- 2,122
4
votes
1
answer
1k
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Callan-Gross relation validity
The inelastic electron-proton scattering cross section can be written as
$$\frac{d\sigma}{dE_2d\Omega}=\frac{\alpha^2}{4*E_1\sin^4{\frac{\theta}{2}}}(W_2\cos^2{{\frac{\theta}{2}}}+2W_1\sin^2{{\frac{\...
- 263
5
votes
2
answers
404
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Valence sea quarks parton distribution functions
There's somethin from Thomson (Modern Particle Physics) that I am a little mythed by.
Section 8.4.3, eq. 8.3 is given as
$$
\frac{F^{\mathrm{en}}_2(x)}{F^{\mathrm{ep}}_2(x)}=\frac{4d_{V}(x)+u_{V}(x)+...
- 1,634
0
votes
1
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809
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The counting of all possible baryons quark combinations
I would like to ask how do you count the number of possible quark combination that could possibly exist in a baryon. I know certain spin symmetry or orbital momentum symmetry have to be conserved. But ...
- 1,239