Are neutrons the cause of the weak force?

[MarkE]

Can the weak interaction / beta decay / radioactivity occur without the presence of neutrons? Half-life is based on the degeneration of neutrons, which is measurable because it's time-bound, so I presume that radioactivity is not something between protons and neutrons, but actually caused by neutrons?

Edited August 18, 2017 by MarkE

[Strange]

Beta decay can occur when either a neutron changes to a proton or vice versa so neutrons are not exclusively involved. The weak interaction is the "cause" of beta decay. Protons, neutrons, electrons, neutrinos and gamma photons are all involved (all required) but are not the cause.

https://en.wikipedia.org/wiki/Beta_decay

[MarkE]

I see, but which quark is responsible, the up quark or the down quark?

[Strange]

As far as  know, it can go either way: up to down or down to up.

[Sensei]

3 hours ago, MarkE said:

Can the weak interaction / beta decay / radioactivity occur without the presence of neutrons? Half-life is based on the degeneration of neutrons, which is measurable because it's time-bound, so I presume that radioactivity is not something between protons and neutrons, but actually caused by neutrons?

 

There are 6 beta decay nuclear transformations:

 

Beta decay plus (aka "positron emission"), proton changes to neutron and releases positron to conserve charge, and neutrino to conserve Lepton number.

https://en.wikipedia.org/wiki/Positron_emission

Beta decay minus, neutron changes to proton and releases electron to conserve charge, and anti-neutrino to conserve Lepton number.

https://en.wikipedia.org/wiki/Beta_decay

 

Double beta decay plus, releases two positrons and two neutrinos.

Double beta decay minus, releases two electrons and two anti-neutrinos.

https://en.wikipedia.org/wiki/Double_beta_decay

 

Double beta decay plus neutrinoless, releases two positrons and no neutrinos.

Double beta decay minus neutrinoless, releases two electrons and no anti-neutrinos.

https://en.wikipedia.org/wiki/Double_beta_decay#Neutrinoless_double_beta_decay

 

Example of weak interaction which does not originate from proton/neutron is decay of muon

[math]\mu^- \rightarrow e^- + \bar{v}_e + v_{\mu}[/math]

[math]\mu^+ \rightarrow e^+ + v_e + \bar{v}_{\mu}[/math]

https://en.wikipedia.org/wiki/Muon

 

 

During the first stage of fusion, diproton, Helium-2, sometime decays by positron emission and changes to Deuterium:

[math]_2^2 He \rightarrow _1^2 D + e^+ + v_e[/math]

https://en.wikipedia.org/wiki/Isotopes_of_helium#Helium-2_.28diproton.29

 

Edited August 18, 2017 by Sensei

[swansont]

4 hours ago, MarkE said:

Can the weak interaction / beta decay / radioactivity occur without the presence of neutrons? Half-life is based on the degeneration of neutrons, which is measurable because it's time-bound, so I presume that radioactivity is not something between protons and neutrons, but actually caused by neutrons?

Any decay involving the change of flavor of a quark is due to the weak interaction. There are a bunch of particles that do this that are not a neutron. 

3 hours ago, MarkE said:

I see, but which quark is responsible, the up quark or the down quark?

The quark is not "responsible" for the decay.

[MarkE]

Ok, so radioactive decay DOES happen the other way around via positron emission, but it doesn't happen naturaly in nature. To me it sounds the same like stating that 2nd and 3rd generation particles also 'exist' because they have existed for a millionth of a second. That's not the same type of existing.

44 minutes ago, swansont said:

The quark is not "responsible" for the decay.

Since there is no outside cause needed for radioactive decay, it should have an inside cause, right? It might be just too small too detect, but nothing happens spontaneous without a cause. "We call decay spontaneous because it is not triggered by anything we know of", as A. Neumaier once said. 

1 hour ago, swansont said:

Any decay involving the change of flavor of a quark is due to the weak interaction. There are a bunch of particles that do this that are not a neutron. 

Which particles are you referring to?

[Sensei]

10 minutes ago, MarkE said:

Ok, so radioactive decay DOES happen the other way around via positron emission, but it doesn't happen naturally in nature.

Positron emission (beta decay plus) does not happen often on the Earth, but it happens all the time in the core of the Sun.

Currently approximately 1.8344*10^38 times per second.

Edited August 18, 2017 by Sensei

[MarkE]

19 minutes ago, Sensei said:

Positron emission (beta decay plus) does not happen often on the Earth, while it happens all the time in the core of the Sun. Currently approximately 1.8344*10^38 times per second.

Right, but there is very little radioactivity in the products of nuclear fusion.

Could you state that going from proton to a neutron (in the sun) does not create harmful radioactivity, whereas from a neutron going to a proton (on earth) does?

Edited August 18, 2017 by MarkE

[Sensei]

36 minutes ago, MarkE said:

Right, but there is very little radioactivity in the products of nuclear fusion.

They are created all the time, but they have short half-lives, and remain in the core of star, until supernova explosion.

 

36 minutes ago, MarkE said:

Could you state that going from proton to a neutron (in the sun) does not create harmful radioactivity, whereas from a neutron going to a proton (on earth) does?

Majority of radioactive isotopes here on the Earth have origin in Uranium-235 with 704 millions years half-life, and Uranium-238 with 4.468 bln years half-life. Both are very little radioactive (long half-lives). But daughter isotopes created by them are short-living isotopes. And daughter of daughter are also unstable etc. etc. They are decaying until they reach Pb, or other stable isotope.

They were created in supernova explosion billions years ago. During supernova free neutrons are created and are captured by heavy nucleus like Iron, Nickel, or other present in the core.

Neutrons can be rapidly captured, in r-process.

https://en.wikipedia.org/wiki/R-process

Neutrons can be slowly captured, in s-process.

https://en.wikipedia.org/wiki/S-process

Protons can be captured, in p-process

https://en.wikipedia.org/wiki/P-process

Protons can be rapidly captured, in rp-process

https://en.wikipedia.org/wiki/Rp-process

 

Edited August 18, 2017 by Sensei

[MarkE]

@Sensei Thanks! I will read into that! (I've never heard of R and P process before).

Could you tell me whether my last statement, about the harmfulness of radioactivity, was right or not?

[Sensei]

6 hours ago, MarkE said:

Could you tell me whether my last statement, about the harmfulness of radioactivity, was right or not?

Radioactivity is no doubt harmful.

Even scientists working on Manhattan project had chance to feel it by themselves... they died in accidents:

https://en.wikipedia.org/wiki/Harry_Daghlian

https://en.wikipedia.org/wiki/Louis_Slotin

 

[MarkE]

That's true!

Did you see the documentary 'The coming war on China'? It's about the effects of harmful radioactivity on people back in the 50s, due to nuclear weapons that were being tested on the Bikini Atoll and other Marshall Islands. A very interesting documentary if you ask me.

But actually my question was not only whether radioactivity is harmful or not, it was: 'Could you state that going from proton to a neutron (in the sun) does not create harmful radioactivity for us, whereas going from a neutron to a proton (on earth) does?'. In your answer I didn't find a yes or no ;).

Thanks for answering!

Edited August 18, 2017 by MarkE

[swansont]

On 8/18/2017 at 9:46 AM, MarkE said:

 Since there is no outside cause needed for radioactive decay, it should have an inside cause, right? It might be just too small too detect, but nothing happens spontaneous without a cause. "We call decay spontaneous because it is not triggered by anything we know of", as A. Neumaier once said.

Then again, if there is no known cause, perhaps there is no cause.

Quote

Which particles are you referring to?

https://en.wikipedia.org/wiki/List_of_baryons
https://en.wikipedia.org/wiki/List_of_mesons

[MarkE]

@swansont You said 'The quark is not responsible for the decay' and 'There are a bunch of particles that do this that are not a neutron' but you were referring to baryons and mesons... which are neutron particles. So how could they not be responsible for decay then?

[Strange]

2 minutes ago, MarkE said:

@swansont You said 'The quark is not responsible for the decay' and 'There are a bunch of particles that do this that are not a neutron' but you were referring to baryons and mesons... which are neutron particles. So how could they not be responsible for decay then?

A neutron is a specific example of a baryon. There are other baryons and mesons that are not neutrons.

[swansont]

A neutron is a baryon, but most baryons are not neutrons. Neutrons are not mesons, and no meson is a neutron.

The particle(s) "responsible" (which is an awkward description) are the W and Z bosons.

https://en.wikipedia.org/wiki/W_and_Z_bosons

 

edit: xpost with Strange

[MarkE]

Thanks for pointing that out.

Do neutrons differ in any way from protons regarding radioactivity? Could you for instance state that mutating from a proton to a neutron (inside the core of the sun) does not create harmful radioactivity for us people, whereas mutating from a neutron to a proton (inside unstable atoms on earth) does?

[Strange]

3 minutes ago, MarkE said:

Thanks for pointing that out.

Do neutrons differ in any way from protons regarding radioactivity? Could you for instance state that mutating from a proton to a neutron (inside the core of the sun) does not create harmful radioactivity for us people, whereas mutating from a neutron to a proton (inside unstable atoms on earth) does?

Standard beta decay can go both ways (beta+ and beta-) and produce similar radiation (high energy electrons or anti-electrons). I'm not sure that either is less bad than the other. https://en.wikipedia.org/wiki/Beta_decay#Description

But I am curious, why do you ask this?

[Sensei]

43 minutes ago, Strange said:

Standard beta decay can go both ways (beta+ and beta-) and produce similar radiation (high energy electrons or anti-electrons). I'm not sure that either is less bad than the other. https://en.wikipedia.org/wiki/Beta_decay#Description

Anti-electrons (aka "positrons") are later annihilating with electrons, producing high energy gamma photons. Thus this decay mode can be much more dangerous than just plain beta decay minus. Tritium (the only decay mode is beta decay minus) is so small radioactive that it's used in watch clocks. Each unstable isotope, each unstable particle, has to be analyzed independently from other. Their half-lives are different. They release different energy. You must analyze of what is their daughter isotopes and the all their decay paths.

 

Edited August 20, 2017 by Sensei

[swansont]

They differ in that a free proton will not decay. Neutrons will; they have more mass.

16 minutes ago, Sensei said:

Anti-electrons (aka "positrons") are later annihilating with electrons, producing high energy gamma photons. Thus this decay mode can be much more dangerous than just plain beta decay minus. Tritium (the only decay mode is beta decay minus) is so small radioactive that it's used in watch clocks. Each unstable isotope, each unstable particle, has to be analyzed independently from other. Their half-lives are different. They release different energy. You must analyze of what is their daughter isotope and the all its decay paths.

The photons can actually make the beta plus decay less dangerous, all else being equal. Gammas can go through you, and so represents energy that's not deposited in you for a source inside your body.

[Sensei]

25 minutes ago, swansont said:

The photons can actually make the beta plus decay less dangerous, all else being equal. Gammas can go through you, and so represents energy that's not deposited in you for a source inside your body.

Analyze two situations:

1) somebody ingest unstable isotope which is decaying by beta decay minus exclusively, daughter isotope is stable, let's say up to 400 keV energy electrons are created. High energy electron fly through body, ionizing atoms, destroying molecules through which it flies. Electron decelerate giving away its kinetic energy to surrounding matter. And it's end.

2) somebody ingest unstable isotope which is decaying by beta decay plus exclusively, daughter isotope is stable, let's say up to 400 keV energy positrons are created. The same half-life as in the 1st case. The same energy released by the event. High energy positron fly through body, ionizing atoms, destroying molecules through which it flies. High energy positron decelerate giving away its kinetic energy to surrounding matter, and finally it's annihilating with some random atom electron in random molecule in body (molecule is destroyed, goes random chemical reaction with surrounding it molecules). And now finally you have 2 or more gamma photons that passes through body, and perhaps scattering, ionizing random atoms and molecules, if/when they interacted..

 

[swansont]

1 hour ago, Sensei said:

Analyze two situations:

1) somebody ingest unstable isotope which is decaying by beta decay minus exclusively, daughter isotope is stable, let's say up to 400 keV energy electrons are created. High energy electron fly through body, ionizing atoms, destroying molecules through which it flies. Electron decelerate giving away its kinetic energy to surrounding matter. And it's end.

2) somebody ingest unstable isotope which is decaying by beta decay plus exclusively, daughter isotope is stable, let's say up to 400 keV energy positrons are created. The same half-life as in the 1st case. The same energy released by the event. High energy positron fly through body, ionizing atoms, destroying molecules through which it flies. High energy positron decelerate giving away its kinetic energy to surrounding matter, and finally it's annihilating with some random atom electron in random molecule in body (molecule is destroyed, goes random chemical reaction with surrounding it molecules). And now finally you have 2 or more gamma photons that passes through body, and perhaps scattering, ionizing random atoms and molecules, if/when they interacted..

 

I said all else being equal. Same total energy available to be deposited.

[MarkE]

On 20/08/2017 at 5:35 PM, Strange said:

Standard beta decay can go both ways (beta+ and beta-) and produce similar radiation (high energy electrons or anti-electrons). I'm not sure that either is less bad than the other. https://en.wikipedia.org/wiki/Beta_decay#Description

But I am curious, why do you ask this?

"Beta-plus decay can only happen inside nuclei when the absolute value of the binding energy of the daughter nucleus is greater than that of the parent nucleus, i.e., the daughter nucleus is a lower-energy state" (Wikipedia). I don't really understand what this means, do you?

I'm curious because I hypothesize that the down quark is not 'responsible' for the same forces as the up quark is.

[Strange]

35 minutes ago, MarkE said:

"Beta-plus decay can only happen inside nuclei when the absolute value of the binding energy of the daughter nucleus is greater than that of the parent nucleus, i.e., the daughter nucleus is a lower-energy state" (Wikipedia). I don't really understand what this means, do you?

It simply says that decay can only happen when it results in a lower energy configuration. This is true of all types of decay, as far as I know. This is why free neutrons decay into protons (which have lower mass) and why they generally don't decay in atoms.

Quote

I'm curious because I hypothesize that the down quark is not 'responsible' for the same forces as the up quark is.

Well, neither are responsible for forces, so it isn't clear what this means. But do you have any evidence for this hypothesis?

p.s. "Wikipedia" is not a useful reference. You might as well say "a book" or "someone said".

p.p.s The particles "responsible" for the weak interaction are the W and Z bosons.

https://en.wikipedia.org/wiki/Weak_interaction

Edited August 24, 2017 by Strange