What kinds of particles can decay to Lambda hyperons?

In summary, you are looking for particles that frequently produce Lambdas. You find some that produce Lambdas often, and look for heavier baryons that have two light quarks (up/down) and one heavier quark (especially strange and charm, but also bottom). Z and W can also produce Lambdas, but they are rare.
  • #1
Chenkb
41
1
Such as ##\Sigma^0 \to \bar{\Lambda}\gamma\gamma##.

I want to make a complete collection of all these decay modes, i.e.

##X \to \Lambda / \bar{\Lambda} + \cdots##.

At least some major channels.
 
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  • #2
wouldn't the pdg help you?
 
  • #3
ChrisVer said:
wouldn't the pdg help you?

Ok, it's easy to find the ##\Lambda## decay mode in PDG, but not so easy to do it inversely I think.

If there isn't a ready-made collection, I'll try to search one by one in PDG.

Thanks all the same.
 
  • #4
Any baryon weighing more than 1115 MeV.
Any other particle weighing more than 2230 MeV.
 
  • #5
Vanadium 50 said:
Any baryon weighing more than 1115 MeV.
Any other particle weighing more than 2230 MeV.

:eek:Really?
 
  • #6
Chenkb said:
:eek:Really?
Those numbers are not exact, but yes. As long as conservation laws can be conserved, a decay is possible. Many of them are very unlikely, however.

I guess you look for particles that frequently produce Lambdas? Then look for baryons with two light quarks (up/down) and one heavier quark (especially strange and charm, but also bottom). In addition, some B-mesons can decay to lambda+X.

Z and W can produce lambdas as well, but those are quite rare. For very high-energetic lambdas, they might be relevant.

Where/how do you want to use such a collection?
 
  • #7
mfb said:
Z and W can produce lambdas as well, but those are quite rare.

Not as much as you think. The mean number of lambdas in a Z-decay is about 0.4.
 
  • #8
Vanadium 50 said:
The mean number of lambdas in a Z-decay is about 0.4.

What did you mean by 0.4?
##\frac{\sum Z \to {\Lambda}/\bar{\Lambda} + X}{\sum Z \to X}## = 40% ?
 
  • #9
No, I mean that in a sample of a million Z decays there are 400,000 Lambdas. It's a statistical statement, not event by event.
 
  • #10
If you are looking for things beside short-distance production and the Z production just look at any heavier baryonic resonance and see what can give you the most Lambdas. Your end goal is a [uds]. So you can have some

##[uds]^* \to [uds] + (f \bar{f},\pi \pi, \gamma)## Resonant decays ##[\Lambda^*]##
##[udc] \to [uds] + \left(f \bar{\nu}_f, \pi^{+}, \rho^{+}, etc\right) ## electroweak decays ##[\Lambda_c, \Sigma_c, \Xi_c]##
##[udb]-> [uds] + f \bar{f}## (FCNC, highly suppressed) ##[\Lambda_b, \Sigma_b, \Xi_b]##
 
  • #11
Vanadium 50 said:
Not as much as you think. The mean number of lambdas in a Z-decay is about 0.4.
I meant Z and W are rare. Even with a branching fraction of 100% they would be a small contribution.

At the LHC, the cross-sections are 100nb for the W and 30nb for the Z (ATLAS result at 7 TeV).

I didn't find a proper cross-section measurement of the lambda at the LHC, but an approximate number of 100µb given here (note: those lines are "100 events"), and I think this is restricted to the LHCb acceptance - that means the total cross-section is significantly higher. For the total number of lambdas, W and Z contribute less than .1%. That number could be larger for large transverse momentum.

For all other accelerators, the energy is lower, and the W/Z cross-section goes down faster than the other production modes, so there the contribution is even smaller (unless you run an electron-positron collider at the Z peak, of course).

I found a master thesis with a collection of (predicted) mother particles for Lambdas at LHCb.
 

What is a Lambda hyperon?

A Lambda hyperon, also known as a Lambda particle, is a subatomic particle that contains a strange quark and a down quark. It has a mass of approximately 1,115.6 MeV/c^2 and a spin of 1/2.

What particles can decay to Lambda hyperons?

Particles that can decay to Lambda hyperons include neutral pions, charged pions, kaons, and Sigma hyperons. These decays occur through the strong and weak nuclear forces.

How do scientists detect decays to Lambda hyperons?

Scientists use particle detectors, such as detectors at the Large Hadron Collider, to measure the properties and trajectories of particles. By analyzing the data collected from these detectors, scientists can identify decays to Lambda hyperons.

Why is the study of Lambda hyperon decay important?

The study of Lambda hyperon decay is important because it can provide insights into the fundamental forces and interactions that govern the behavior of subatomic particles. It can also help scientists better understand the composition and evolution of the universe.

Are there any current experiments or projects focused on studying Lambda hyperon decay?

Yes, there are several experiments and projects currently focused on studying Lambda hyperon decay. These include the LHCb experiment at the Large Hadron Collider, the Belle II experiment in Japan, and the GlueX experiment at Jefferson Lab in the United States.

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