# Could Excited Baryon decay into omega meson and baryon?

1. Dec 24, 2014

### zhangyang

Excited baryon could decay into photon and ground state baryon,but could it decay into omega meson and ground state baryon?Could you introduce me some articles about it,experimental or theoretical?

2. Dec 24, 2014

Staff Emeritus
There are many excited baryons. Which one are you talking about?

3. Dec 24, 2014

### ChrisVer

There are excited baryons that can undergo several decays....
If the conservation laws are satisfied then the decay can exist...
Take for example the $\Delta^+$ baryon which is an excited proton, and it decays to proton via:
$\Delta^+ \rightarrow p + \pi^0$
(no photon)

So I don't see why there can't be an omega-meson participating in such processes. The only problem of omega, in comparison to pions, is its large mass...

4. Dec 24, 2014

### zhangyang

Could any excited baryon decay into ? Even One,I want to search its information.If it exist,which one is most likely to occur?

5. Dec 24, 2014

### zhangyang

From theoretical respect,yes.But every unstable particle has its favorate mode of decay,so we could at last determine it through experiment.Has that process been discovered ?

6. Dec 24, 2014

### ChrisVer

Then I'd say omega meson is not a favorite decay mode, due to its large mass (small phase space relative to others).
Or are you refering to the Delta+ decay I wrote? Then it's 1 of the 2 most common decays of the Delta+ baryon , and the one that results in a proton [un-excited state] product...

7. Dec 24, 2014

Staff Emeritus
The N(1875), provided that it is real, has a 20% branching fraction to omega + N.

8. Dec 24, 2014

### Staff: Mentor

There are multiple mesons called $\omega$. I guess we are talking about the lightest one at 782 MeV.
You can look through the decay modes of http://pdg8.lbl.gov/rpp2014v1/pdgLive/Viewer.action [Broken]. You'll see that a large variety of baryons has reasonable branching ratios with an omega meson. Most of those particles are so short-living that their widths overlap, and you cannot clearly identify the origin of each omega meson individually.
$\Lambda_c^+$ has a 1.2% chance to decay to $\Lambda \pi^+ \omega$. While this might be a rare production mode, the long lifetime of the mother particle can be interesting.

What do you want to do/know?

Last edited by a moderator: May 7, 2017
9. Dec 25, 2014

### zhangyang

Thank you,I will search it in PDG carefully.So heavy a meson.
Somebody say that J/ψ→excited B + antiB + excited(antiB) + B → ω + B + antiB could occur,(B point to baryon),I feel surprised,because I think J/ψ and ω is in an same generation,but in the process above ,former is the mother's mother of latter,so I want to determine the truth.

10. Dec 25, 2014

### zhangyang

The mechanism is weak interaction? Maybe, to research the hadron decay ,one always has to treate weak interaction,perhaps it implies the connection between Strong and Weak interaction.
Thank you.

11. Dec 25, 2014

### zhangyang

Someone researched the radiative decay of excited baryon ,which is from the decay of J/ψ:
J/ψ→excited B + antiB + excited(antiB) + B → photon + B + antiB ,
use the partial wave analysis to abtain the quantum amplitude of process,and the branch ratio ,other thought that the photon could be replaced by Omega,and the process could also occur,I suspect it,that is it.

Last edited by a moderator: May 7, 2017
12. Dec 25, 2014

Staff Emeritus
If you expect us to have a discussion on this, it would be helpful to know who this "somebody" is, and where it was published.

13. Dec 25, 2014

### ChrisVer

It can be a strong interaction.
There is hardly any connection between strong and weak interactions at this stage.

14. Dec 26, 2014

### vanhees71

In my research field of high-energy heavy-ion collisions, plenty of omega mesons are created. The light vector mesons ($\rho$, $\omega$, and $\phi$) play a very important role in understanding the findings on "dileptons". Dileptons are simply electron-positron or muon-antimuon pairs. Plenty of those are created in a heavy-ion collision, and taking their invariant-mass spectra measures a quantity called the electromagnetic current-current correlation function of hadrons.

That's a very interesting signal to learn about the hot and dense medium created in high-energy heavy ion collisions, because the leptons (and also photons) don't take part in the strong interaction, and thus for them the hot and dense medium is transparent, i.e., the dileptons do not suffer final-state interactions but come out of the hot and dense fireball pretty undistorted and thus give a signal from the hot and dense interior.

Among the mechanisms to create dileptons in such collisions are also the decays of the light vector mesons, and thus by measuring the dilepton's invariant-mass spectra you can find out something about the change of the spectral properties of the light vector mesons. It turns out that models that predict a large broadening of the spectral function with quite small mass shifts describe all the data at a large varieties of collision energies pretty accurately.

In turn this tells as something about the mechanism underlying the restoration of the (approximate) chiral symmetry of the light-quark sector in QCD: It's a "melting of the resonances", i.e., the resonances become very broad around the transition between a hot and dense hadron gas and a state of matter, called the "Quark Gluon Plasma", which consists of a strongly coupled gas (or liquid?) of quarks and gluons. For a pretty recent review, see, e.g.,

R. Rapp, J. Wambach, H. van Hees, The Chiral Restoration Transition of QCD and Low Mass Dileptons
Landolt-Börnstein, Volume I/23, 4-1 (2010)
arXiv: 0901.3289 [hep-ph]

15. Jan 11, 2015

### zhangyang

I upload the article.But I haven't know the complete formalism of partial wave analysis,so I want to get a initial paper on this,do you have ?

16. Jan 11, 2015

### vanhees71

I'd not post a copyrighted paper in a publicly available forum. I'm not sure, whether the APS is strict about this, but it can get expensive. In HEP that's not necessary anyway, because usually everything is also posted to arXiv, and that's the case also here:

http://arxiv.org/abs/hep-ph/0210164

17. Jan 12, 2015

### zhangyang

Yes,I want to delate the article I upload,How could I operate?

18. Jan 12, 2015

### Staff: Mentor

I deleted the attachment.