[Physics] Sigma+ quark structure


Does sigma+ have 2 quark structures, if so are they uus and (anti)d (anti)d (anti)s ? Both these structures are the same charge (+) so I guess it would make sense however I can't find much about it online anywhere.

Best Answer

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I appreciate this is a cut and paste answer, (which I detest) because I would rather rewrite it to learn something from, but it's 1.00 am here so.... but if you click on the link below it might help. The website below has not been maintained, so you might take a while to resolve it on your machine, sorry.

Extracts From: Sigma Bayon

The sigma is a baryon which contains a strange quark. The quark composition of the three different sigmas is shown above. The three varieties have similar masses and are said to be an isospintriplet. The only baryon with a strange quark which is less massive than the sigma is the neutral lambda baryon. The neutral sigma can decay to the lambda without violatingconservation of strangeness, so it proceeds rapidly by the electromagnetic interaction. The sigma-zero and lambda-zero have the same quark constituents so the sigma-zero can be considered to be an electromagnetic excited state of the lambda-zero. The charged sigmas have no decay path which does not involve the transmutation of the strange quark, so their decays are much slower, proceeding only by the weak interaction.

According to the Particle Data Book, the branching ratio for the decays of the sigma-plus is 51.57% for the pπ0 pathway and 48.31% for the nπ+ pathway. This near equivalence is really surprising to me - the neutron pathway looks a lot harder.