Timeline for Experimental proof for isospin conservation of strong interaction
Current License: CC BY-SA 4.0
12 events
| when toggle format | what | by | license | comment | |
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| Sep 30, 2019 at 12:31 | comment | added | avitase | No, I just want to reference examples where predicting non-zero branching fractions with CG and Isospin conservation actually works. Sorry for being unprecise. | |
| Sep 30, 2019 at 11:26 | comment | added | Cosmas Zachos | Oh, I read it as a search for violations, not absence of dynamical corrections to the perfect symmetry limit... | |
| Sep 30, 2019 at 9:08 | comment | added | avitase | Actually I was asking for cases where CG predict roughly the right branching fractions... | |
| Sep 29, 2019 at 22:08 | comment | added | Cosmas Zachos | Not really, given details of phase space availability and all kinds of particularities... Possibly deserving its own question; I have no idea how well such Clebschings work across all contexts. But, in the actual question answered we are fussing about several orders of magnitude. | |
| Sep 29, 2019 at 21:11 | comment | added | avitase | It is the difference between 60% (measured) and 1/3 (CG), i.e. 2x more $\Sigma^0$ than $\Lambda$ than predicted from isospin conservation. I think this is quite large? | |
| Sep 29, 2019 at 16:17 | comment | added | Cosmas Zachos | Oh, fair enough, yeah, a factor of 0.6 is not that big of a deal.... | |
| Sep 29, 2019 at 15:55 | comment | added | avitase | I thought that the squared CG coeff, i.e $3$, not $\sqrt{3}$, has to be considered when looking at branching ratios? | |
| Sep 29, 2019 at 15:14 | comment | added | avitase | Besides the fact, that your explanation is very helpful, I am still looking for a measurement, where Clebsch-Gordan coeffs. predict roughly the correct branching ratio, similar to my example of the $\Delta$ decays, where I don't find references though, which is quite unfortunate, since I expect QED effects to be quite small here (?). | |
| Sep 29, 2019 at 15:09 | comment | added | avitase | Thanks a lot for these in-depth explanations, much appreciated! Glad that you mention the $J/\psi$ decay, since I never understood the measured branching ratio $J/\psi \to 2\Lambda$ vs $J/\psi \to 2 \Sigma^0$ of ~60%. CG coeffs. give me 1/3 for QCD and even QED (since QED contributes only one diquark, which can then form either $I=1$ or $I=0$, all other quarks are iso-singlets and since $2 \Sigma^0$ can be either $I=2$ or $I=0$, but not $I=1$ QED is in that sense also (accidently) isospin conserving). I cannot belief, that this factor of 2 comes from isospin breaking QCD effects? | |
| Sep 29, 2019 at 13:44 | history | edited | Cosmas Zachos | CC BY-SA 4.0 |
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| Sep 28, 2019 at 21:12 | history | edited | Cosmas Zachos | CC BY-SA 4.0 |
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| Sep 28, 2019 at 19:16 | history | answered | Cosmas Zachos | CC BY-SA 4.0 |