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Does the strong (nuclear) force ever contribute to decay ? Or is the weak nuclear force the only decaying force ?

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    $\begingroup$ Yes. The clearest example of strong-mediated decay would be alpha decay, but there are a lot of examples. $\endgroup$ Commented Oct 22, 2012 at 13:48
  • $\begingroup$ Is that explained somewhere well ? Wiki ? $\endgroup$
    – mick
    Commented Oct 22, 2012 at 13:49
  • $\begingroup$ How much physics background do you have? At the popular level, nuclear binding energy is mostly determined by the strong force. Anything that has its energy production governed by that is going to be mostly strong-mediated. $\endgroup$ Commented Oct 22, 2012 at 13:52
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    $\begingroup$ The OP asked whether the strong force "contributes" to decay. I'm not sure I'd interpret the strong force as contributing to alpha decay. As the alpha tunnels out, it's feeling both strong and electrical forces. The strong force is attractive, so if anything, it's hindering the decay. The reason there's a big release of energy (which is why alpha decay happens so frequently in nature) is the electrical force. $\endgroup$
    – user4552
    Commented May 3, 2013 at 0:58

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Most of the resonances detected in particle physics scattering experiments are bound states of the strong force, bound for a time interval before decay .

These are created in the interaction and seen in invariant mass combinations of the interaction products, statistically.

The distinction with electromagnetic or weak decays comes from the widths of the resonances: the strong decays have MeV widths, whereas weak and electromagnetic decays are at the experimental error.Tables of delta resonances and N resonances etc can be found in the particle data booklet.

lamda strong

Here the invariant mass of a proton K pair shows a lamda resonance induced by the strong force.

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  • $\begingroup$ Ah, but does the strong force (repulsive sometimes at extremely short distances, due to Pauli exclusion I believe) actually CAUSE the decay of one of these extremely short-lived resonance baryon, or does the strong force merely fail to hold the particle together for very long? $\endgroup$
    – Kurt Hikes
    Commented Jun 10, 2021 at 19:49
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    $\begingroup$ @KurtHikes you may take either view. If the strong force did not exist there would be no hadronic resonances, so, imo, it is the cause that creates the effect of the resonance. $\endgroup$
    – anna v
    Commented Jun 11, 2021 at 4:44
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The difference between strong force decay and weak force decay is that the strong force decay is applicable to only quarks. Also the quarks have to be the same flavor. For example the flavor should be say up quark and antiup quark. They will annihilate into a gluon and that gluon can decay into other quarks. Also the weak force could theoretically annihilate two quarks that are in the same generation but have different charges. The weak force is usually involved in decays. However when the strong force is involved the decays happen much faster. This is because the strong force is the strongest force.

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