Comprehensive List of Subatomic Particle Decay Modes and Probabilities

In summary, the conversation is about finding a comprehensive list of decay modes and probabilities for all known subatomic particles. The website http://pdg.lbl.gov/ is recommended as a reliable source for this information. The possibility of finding similar charts for annihilation events between particles and antiparticles at low energies is discussed, with a focus on proton-antiproton and neutron-antineutron annihilation. Theoretical predictions for branching ratios are also mentioned. A question is posed regarding the distribution of probabilities for neutron-antineutron annihilation.
  • #1
trilex1
10
0
Hello

I'm looking for a list,as complete as possible, of decay modes and their probabilities, for all known subatomic particles.
I've been googling, but found only bits and pieces. Perhaps someone knows a place on internet, or has found a free document to share, or anything like that

thanks
 
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  • #3
Astronuc said:
The data is probably buried in here

http://pdg.lbl.gov/2007/listings/contents_listings.html


Moreover, for the total decay rates, when known, there is an spreadsheet in the same node. It could contain still a couple typos, be alert.
http://pdg.lbl.gov/2006/html/computer_read.html
http://pdg.lbl.gov/2007/mcdata/mass_width_2006.csv

Time ago I explained how to plot this spreadsheet, see comment 1 here: http://dorigo.wordpress.com/2006/09/14/a-mistery-behind-the-z-width/
Gnuplot is also available in windows.

Contest idea: please upload in this thread your best plots of this data o:)
 
  • #5
Now, are there similar charts in existence for annihilation events between various particles and antiparticles at low energies ("static")? In other words, should I even look for such a thing?
 
  • #6
trilex1 said:
Now, are there similar charts in existence for annihilation events between various particles and antiparticles at low energies ("static")? In other words, should I even look for such a thing?

You are asking for collision cross-sections, are you?
 
  • #7
Well, this is all pretty new for me, so I'm not sure if that's what it's called

but what I'm looking for would be branching ratios of various outcomes of annihilation at rest. Between protons-antiprotons, electron-positrons and neutron-antineutrons.
 
  • #8
trilex1 said:
Well, this is all pretty new for me, so I'm not sure if that's what it's called

but what I'm looking for would be branching ratios of various outcomes of annihilation at rest. Between protons-antiprotons, electron-positrons and neutron-antineutrons.
Well for static situation with electron-positron annihilation the result is two photons of 0.511 MeV. For nucleons, I don't think there are too many (if at all) static collisions, since anti-protons are produced at high energies, and I'm not sure any have been brought to rest unless someone at CERN or Fermilab has done it (?).

I doubt antineutrons have been produced at rest.
 
  • #9
Well they do have antiproton decelerator at CERN and other methods of cooling down anti-protons, so if not total rest, they certainly can get the energy down to change results

In the meantime , I finally found the branching ratios for p anti-p

here is one table, this is from a PDF presentation made by Ryugo Hayano, of University of Tokyo , and he has been working at CERN, so I trust the table to be reliable representation of Cern experiments, although it is not quoted as such, but
I had to compare its numbers to another similar table, although simplified, which used same numbers and claimed them to be results from experiments at CERN, of annihilation at rest. I don't know if it was really at rest or at low enough energy so that results don't deviate much from predictions at rest, but here it is:

http://free-os.t-com.hr/redmist/pp.jpg [Broken]

This one uses quite a bit of channels , including Kaons , while other sources usually disregard kaons, and group various channels together. This one is the most specific I could find so far.

I made a jpg , it's extracted from the PDF.

credits to mr. Hayano

http://athena-positrons.web.cern.ch/ATHENA-positrons/wwwathena/Hayano.html [Broken]
 
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  • #10
Hey, where is the pdf? It is a impressive work from the experimental side; I wonder if the theoreticians are at the same level about calculating these branching rations. I had expected first the 3 pions channels, but it seems they carry a lot of energy yet, so five pions are favored! I'd guess that at least one pair u u* anhiquilates.
 
  • #11
Here it is, but the table is on the end somewhere:

www.oeaw.ac.at/smi/download/aic04/hayano-wien.pdf [Broken]

About the theoretical predictions of branching, It's interesting you brought that up, because I also found a publication comparing calculations with practical observations from Cern, in fact it was compare to this same chart I posted, except that they "dumbed down" the results by merging channels of 2,3,4 etc neutral pions into simply more than one neutral pion.

http://uk.arxiv.org/PS_cache/hep-ph/pdf/9504/9504362v1.pdfAlthough I still haven't found any data on n-nbar annihilation, which will probably be very hard, but I'd settle for theoretical predictions too
 
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  • #12
Here's a question

I've been thinking, but I'm probably wrong..

A neutral pion can have either up-antiup quark pair or down-antidown pair.
A proton-antiproton pair has in total 2 ups, one down, two antiups, and one antidown all together which is a perfect match for making equal amounts of positive, negative and neutral pions,
and a neutron-antineutron pair has all together two downs, two, antidowns, one up and one antiup quark, which is also a perfect match for making equal amounts of positive, negative and neutral pions, allthough the neutral pions would have a much different mass than than u-anti-u neutral pion

So would it be possible to assume that distribution of probabilities would be similar to that of proton-antiproton annihilation, or would a different mass of d-anti-d neutral pions cause a different distribution?

The building blocks are in equivalent amounts in both annihilations, except that
while they are equivalent for the job of forming pions, they are not identical.
 

1. What is a subatomic particle decay mode?

A subatomic particle decay mode is a way in which a subatomic particle transforms into other particles. It occurs when a particle is unstable and undergoes a spontaneous transformation into different particles or energy.

2. What is a comprehensive list of subatomic particle decay modes and probabilities?

A comprehensive list of subatomic particle decay modes and probabilities is a compilation of all known decay modes of subatomic particles, along with their corresponding probabilities of occurrence. This list is constantly updated as new particles and decay modes are discovered through experiments and research.

3. How are decay modes and probabilities determined for subatomic particles?

Decay modes and probabilities for subatomic particles are determined through various experiments and observations, such as particle accelerators and particle detectors. These experiments involve studying the interactions and transformations of particles to determine their decay modes and probabilities.

4. Why is it important to have a comprehensive list of subatomic particle decay modes and probabilities?

A comprehensive list of subatomic particle decay modes and probabilities is important for understanding the fundamental building blocks of our universe. It allows scientists to study and predict the behavior of particles, as well as to make advancements in fields such as particle physics and cosmology.

5. Are subatomic particle decay modes and probabilities always accurate?

While the comprehensive list of subatomic particle decay modes and probabilities is constantly updated and improved upon, there is always a margin of error in the measurements and predictions. This is due to the complex nature of subatomic particles and the limitations of current technology. However, these probabilities are generally accepted as accurate and continue to be refined with new discoveries and advancements.

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