Talk:Particle decay

What happens after an elementary particle decays? Is it just gone?

Yes, the initial particle is "just gone" - it has converted/transformed into its decay products. Jasondet (talk) 05:06, 13 September 2011 (UTC)Reply

Energy or creation of another particle. You guys still don't know why some particles are more stable than others, and what's behind the decay. "It just does" isn't sufficient.98.165.15.98 (talk) 13:13, 23 July 2011 (UTC)Reply

That is not a fair assessment. There is quite a good understanding of why some particles are more stable than others. For example, particles that can decay via strong interactions are much less stable than particles that can decay via weak interactions (due to the larger coupling constant for strong interactions), and heavier particles are in general less stable due to the larger phase space available for decay. Jasondet (talk) 05:06, 13 September 2011 (UTC)Reply

My comment will be specifically concerning the sentence:

This process continues until stable particles (electrons, or up and down quarks) are produced.

which might mislead some readers into thinking that up and down quarks are the final stable state for quarks. However this is not necessarily the case theoretically. See: [[1]]. I suggest this can be rectified by inserting the word usually before "electrons, or up ..." to account for such exceptions.

Billyziege 20:33, 8 March 2007 (UTC)BillyziegeReply

independent of the stability of strange matter the list is inappropriate in the sense that a) pions, neutrons,... consist of up and down quarks and are unstable, b) photons and neutrinos are missing.

In the formula for the decay rate (I think equivalent to what is called 'decay width' in particle phyisics) there should be a symmetry factor of 1/k! for every k identical particles in the final state. —Preceding unsigned comment added by 131.174.17.101 (talk) 12:04, 11 January 2008 (UTC)Reply

Good catch, added. Jasondet (talk) 05:57, 13 September 2011 (UTC)Reply

You guys sure that a neutron decays (on average) in less than 900 seconds ? That would mean that atoms as we know them are all at least that unstable....

...Unless someone can theorize that they constantly recombine again inside the nucleus (which again would be strange, since expelled electrons might eventually escape). Or is a neutron viewed as "just a proton with a closely orbiting electron" thought to decay at the apogee (but that would make 900 seconds way too much)? —Preceding unsigned comment added by 70.54.202.152 (talk) 23:53, 16 September 2008 (UTC)Reply

partial answer:

a) neutron =/= proton+electron; neutron <--> proton+electron+neutrino+energy.

b) neutron= 3 quarks, proton= different 3 quarks. (--> they are fairly complex inside).

c) It is often possible to stabilize an unstable species by giving it an energy-favorable home

which it has to leave the instant it decays. In an atomic nucleus,

the neutron and proton have "fallen" together under the pull of the "strong nuclear force".

(Physics knows 4 forces: gravity, electro-magnetism, strong_nuclear_force, weak_nuclear_force.)

d) think of it as tunneling out of a potential-well, for which probability depends greatly

on the height and thickness of the barrier wall. The electron & neutrino can tunnel out very rarely

(900sec is a long time for particles) but when placed in a low-energy neighborhood inside the nucleus,

it can't succeed for a really long time. jimswen (talk) 00:39, 25 March 2010 (UTC)Reply

Yes, we are sure. The free neutron is unstable, with a lifetime indeed less than 900 seconds, because it is heavier than the sum of the masses of its decay products (proton + electron + electron antineutrino). However, neutrons bound inside nuclei may or may not be stable. Take, for example, the deuteron (the nucleus of ²H, containing 1 proton and 1 neutron). If the neutron inside the deuteron were to decay, you would be left with 2 protons (plus an electron and a neutrino). But the mass of the deuteron is smaller than the mass of two protons thanks to the nuclear binding energy, so that decay is energetically forbidden. Jasondet (talk) 06:18, 13 September 2011 (UTC)Reply

This article is using particle physics nomenclature which has a different meaning that particle decay in nuclear physics. Both concepts are perfectly valid, of course, but the meaning is not the same. I am presently editing the nuclear drip line page, so I may consider creating a nuclear particle decay page. However, in that case, I'd like at least a note at the top that say "did you mean nuclear particle decay" or so. More later, or I may do it myself. Thanks.DAID (talk) 13:01, 6 April 2010 (UTC)Reply

concerning their spin, mesons are bosons. hence the separation of particles into lepton / meson / baryon / boson is inappropriate. the four terms are just not in the same category. suggest to change it to lepton / meson / baryon / _gauge_ boson.

Currently, there are four things wrong with the first paragraph:

• Composite particles can also decay. While there is a sentence clarifying that particle decay "is also used" to refer to hadron decays (as if hadron decays are usually called something else?), it would be better if the first paragraph were correct to begin with.
• Final states of decays can contain composite particles.
• Not all decays have an "intermediate particle" (consider decays of a real ${\displaystyle W}$  or ${\displaystyle Z}$ , or ${\displaystyle t\to Wb}$  or decays forbidden at tree-level). Given that the example is the (virtual) W boson in muon decay, it seems that this sentence was written by someone who takes Feynman diagrams too literally.
• The second sentence "an elementary particle becomes a different particle with less mass" implies that one of the decay products is somehow more associated with the parent particle than the others. If so, which of the photons in ${\displaystyle H\to \gamma \gamma }$  does the Higgs become?

I'm aware of WP:DIY. I just want something to point to in the edit summary.

Dukwon (talk) 11:39, 8 December 2016 (UTC)Reply

Should strong decay link here? — Preceding unsigned comment added by 75.139.254.117 (talk) 09:45, 8 January 2017 (UTC)Reply

I thought proton and electron decay were hypothetical, yet the table lists a mean lifetime for them. It makes it seem like they do actually decay and it just would take a really long time. Maybe an asterisk would make this clearer. I would edit it but I don't actually know for myself whether these are hypothetical or not. Dimmerster (talk) 23:14, 9 May 2024 (UTC)Reply

The neutron lifetime on the table is contradictory with the Wikipedia article on neutron decay (https://en.wikipedia.org/wiki/Free_neutron_decay), which describes the mean lifetime as unknown. WackyAurelionSol (talk) 00:28, 24 July 2024 (UTC)Reply