Why are delta-particles so short-lived?

[shelanachium]

When the quark theory was first proposed, it predicted a new baryon, the omega-minus, to complete a set. It is composed of 3 s quarks.

With the nucleons, containing u and d quarks only, the all-d (delta-) and all-u (delta++) exist only as short-lived 'resonances'. Why is this so, when the all-s omega-minus is directly detectible, e.g in bubble-chambers where it was first seen?

 

[Vanadium 50]

It is energetically allowed for Delta++ to go to p pi+. It is energetically forbidden for the Omega- to make the analogous decay, to Cascade0 K-.

 

[sir-pinski]

Delta-particles, also known as delta baryons, are subatomic particles that are composed of three quarks. These quarks are held together by the strong nuclear force, which is one of the four fundamental forces of nature. The quark theory, also known as the theory of quantum chromodynamics (QCD), predicts the existence of different types of baryons based on the combination of quarks.

The delta baryons are composed of three quarks, with the all-d (delta-) containing two down (d) quarks and one up (u) quark, and the all-u (delta++) containing two up (u) quarks and one down (d) quark. These combinations of quarks result in particles with different properties and characteristics.

One of the reasons why delta-particles are short-lived is because they are not the most stable configuration of quarks. In the QCD theory, the more stable the configuration of quarks, the longer the particle will exist. In the case of delta baryons, the combination of two different types of quarks (d and u) results in a less stable configuration compared to the all-s (omega-minus) which is composed of three s quarks. This makes the delta baryons more prone to decaying into other particles, leading to their short lifespan.

Another reason is the mass difference between the delta baryons and the omega-minus. The omega-minus is a more massive particle compared to the delta baryons, making it easier to detect and observe in experiments such as bubble chambers. The more massive a particle is, the longer it takes for it to decay, giving scientists more time to study and observe its properties.

In summary, the short lifespan of delta-particles can be attributed to their less stable configuration of quarks and the mass difference between them and the more massive omega-minus. While the delta baryons may only exist as short-lived resonances, they still play an important role in our understanding of the subatomic world and the fundamental forces that govern it.