Feynman Diagram: Simga+ -> p + gamma?

[Dr.Brule]

Feynman Diagram: Simga+ --> p + gamma?

Hi,

Can anyone give me some indications as to how to draw the feynman diagram for the following decay?

Ʃ⁺ → p + $\gamma$

Should I consider the quark composition of the sigma first?

Thanks a lot.

 

[Steely Dan]

Should I consider the quark composition of the sigma first?

Thanks a lot.

Indeed. All of the QED/QCD interactions involve individual quarks and leptons, not composite particles. So you want to consider what happens to each quark in the sigma particle independently (at least, to get a first approximation to the decay).

 

[Dr.Brule]

Indeed. All of the QED/QCD interactions involve individual quarks and leptons, not composite particles. So you want to consider what happens to each quark in the sigma particle independently (at least, to get a first approximation to the decay).

So I get how the two u quarks would combine with a d quark to form the proton, but would you get this d quark with the s quark that's left?

Is the process s --> u + anti u ---> ONE gamma allowed?

 

[fzero]

So I get how the two u quarks would combine with a d quark to form the proton, but would you get this d quark with the s quark that's left?

Is the process s --> u + anti u ---> ONE gamma allowed?

No, that process does not conserve electric charge. What weak interaction processes involving quarks did you learn about?

 

[paranormal]

Hello,

To draw the Feynman diagram for this decay, you should first consider the quark composition of the sigma particle. The sigma particle is composed of three quarks: two up quarks and one down quark. Therefore, the Feynman diagram for this decay would involve the interaction of these three quarks.

Next, you should consider the interaction between the quarks and the exchange of particles that leads to the decay. In this case, the sigma particle decays into a proton and a photon. This decay can be represented by the exchange of a W boson, which carries the weak force. The W boson interacts with the down quark in the sigma particle, changing it into an up quark and creating a proton. The W boson also emits a photon, representing the electromagnetic force, which carries away the excess energy from the decay.

Overall, the Feynman diagram for this decay would involve the interaction of the three quarks in the sigma particle, the exchange of a W boson, and the creation of a proton and a photon. I hope this helps!