What Are the Mysteries of Beta Plus Decay in Physics?

  • Context: High School 
  • Thread starter Thread starter abotiz
  • Start date Start date
  • Tags Tags
    Beta Decay
Click For Summary

Discussion Overview

The discussion centers around the concept of beta plus decay in physics, exploring the underlying principles and implications of this decay process. Participants examine the conditions under which beta plus decay occurs, the role of energy states, and the probabilistic nature of decay events. The conversation includes theoretical considerations and conceptual clarifications related to particle behavior and energy conservation.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions how an atom can "know" that the daughter nucleus should have lower total energy for beta plus decay to occur, suggesting a dilemma in understanding this process.
  • Another participant compares the decay process to a ball rolling down a slope, arguing that it does not require prior knowledge of the final state, but rather that decay can happen if a lower energy configuration is available.
  • A different viewpoint emphasizes that the probability of decay can be calculated for different particles, noting that stable particles like protons have a decay probability of zero, independent of neutron mass considerations.
  • Some participants express confusion about the analogy of the ball rolling downhill, with one stating that it is "news" to them, indicating a lack of familiarity with the concept of spontaneous decay.
  • There is a discussion about the nature of probability in decay processes, with one participant asserting that decay does not happen constantly but only when allowed by physical laws.
  • Another participant introduces the concept of conservation laws, specifically energy and momentum, arguing that these principles dictate what is allowed in particle interactions and decay processes.

Areas of Agreement / Disagreement

Participants express differing views on the nature of decay processes, the role of probability, and the implications of conservation laws. There is no consensus on the interpretations of these concepts, and the discussion remains unresolved regarding the deeper understanding of beta plus decay.

Contextual Notes

Some participants mention the need to avoid advanced topics like quantum field theory, indicating that the discussion is limited to a certain level of complexity. There are also references to the challenges of breaking down complex ideas into simpler parts, highlighting the nuanced nature of the topic.

abotiz
Messages
72
Reaction score
0
Hi,

I have a question about beta plus decay.
I have read through the previous post regarding this decay, but I did not find anyone mentioning what I wonder about. Also, some post dates back to 2009, and maybe some recent findings in physics can explain things in a "better" way.

So according to wikipedia "
However, β+ decay cannot occur in an isolated proton because it requires energy due to the mass of the neutron being greater than the mass of the proton.
β+ decay can only happen inside nuclei when the daughter nucleus has a greater binding energy (and
therefore a lower total energy) than the mother nucleus.
"

To me, this implies that the atom knows beforehand that the daughter should have lower total energy.
Which is strange...

If not, then one would say that everything happens, but only the "allowed" things exists.
But this is even more strange.

So, how does the physics explain such a dilemma?

Thank you for your time
 
Physics news on Phys.org
You know how when you place a ball on a slope, it may spontaneously roll down, but it'll never roll up by itself?
Do you find it strange that the ball 'knows' which configuration has lower energy state? Or do you find it strange that it's only 'allowed' for the ball to start rolling down and not up or sideways?

It's exactly like that with decay processes. A ball doesn't have to know where it'll end up beforehand, but if there's anywhere to roll down to, it'll likely roll down. Same with a nucleus - it doesn't have to know what it'll decay into beforehand. As long as there is a configuration with lower energy state available, a decay can happen.
 
  • Like
Likes   Reactions: ORF, Orodruin and mfb
You can calculate the probability that something decays within a given time span, e. g. a second. If you do this calculation for radioactive particles like a free neutron, you get a non-zero value in the calculation. If you do the calculation for stable particles like a free proton, you get exactly zero (at least according to known physics).
The proton does not have to "know" the neutron mass. The proton would behave the same if there wouldn't be a concept of neutrons at all*. If there would be a possible decay, then it could happen at any time, and the probability can be calculated based on the particle properties.*within the scope of this thread. Please don't start with quantum field theory in a [b]-level thread.
 
Bandersnatch said:
You know how when you place a ball on a slope, it may spontaneously roll down.

No, this is news to me.

But if I understood you both correctly, it is something along the lines
abotiz said:
then one would say that everything happens, but only the "allowed" things exists.

Almost like, nucleus gives away its energy in a certain frequency, throws it out and take it in again, and proton is susceptible to decay with a certain frequency, and when the probability matches, it happens.

mfb said:
*within the scope of this thread. Please don't start with quantum field theory in a -level thread.
Sorry Sir, I have no idea what this means.
But last time I made a post I do not remember having to choose something before posting.
Who can tell what a question in physics might generate a kind of answer.
 
abotiz said:
Sorry Sir, I have no idea what this means.
Ignore that part.
There are some technical details where you could argue that my post is not exactly correct, but to understand them you need much more advanced physics. I made that comment to keep these details out, they wouldn't help you.
abotiz said:
Almost like, nucleus gives away its energy in a certain frequency, throws it out and take it in again, and proton is susceptible to decay with a certain frequency, and when the probability matches, it happens.
No, that description does not work.
 
abotiz said:
No, this is news to me.

Wait, go back a few steps, even uphill if necessary. The idea that a ball will, on its own, roll downhill, is "news" to you?

I definitely want to find out first why this is not something you already know.

Zz.
 
mfb said:
No, that description does not work.

Well, would you be so kind to explain?
I really thought that, that summarized both your posts.
That there is a probability for something to happen. And probability happen when things match up or when physics allows it. And it would not make sense that the first time particle A in a complex system "tries" something, things goes its way. It feels like things should happen constantly, and only when allowed, it does happen. Allowed - being governed by physics law.
ZapperZ said:
The idea that a ball will, on its own, roll downhill, is "news" to you?
Yes sir, but I maybe I did not comment that properly. It is for sure the gravitational force causing the roll.
I gave a conservative answer due to chosen word "spontaneous".

Thank you
 
abotiz said:
Well, would you be so kind to explain?
It doesn't make any sense, I can't break that down to smaller parts.
An unstable particle does nothing before it decays. It just stays a particle.
abotiz said:
And probability happen when things match up or when physics allows it.
There is nothing that "matches up".
abotiz said:
It feels like things should happen constantly, and only when allowed, it does happen.
That feeling is wrong.
 
I don't understand well the questions... but there are certain properties in physics that are conserved. The conservation of energy and momentum are so strong principles into the physics community (since they've never been seen violated), that physicists at some point "discovered" a new particle thanks to wanting to keep that principle. That particle was the neutrino. So indeed, everything that is allowed can happen with some probability. Now "what is allowed or not?" is answered by everything is tested everyday.

Yet, conservation of energy and momentum is pretty much anywhere, so you can't say "it knew beforehand", it is made to obey that since nature wants it that way. A particle doesn't know anything beforehand since there is no "conciousness of a single particle" (and you should avoid thinking or even continuing writing on those lines).. It's like trying to feed full 200 people when you only have 1 chip. It's not some kind of previous knowledge but an impossibility for you to do it. In a similar manner it's impossible for nature to "give birth" to extra energy that would be necessary for an isolated proton to decay into a neutron+positron.
 
  • Like
Likes   Reactions: vanhees71

Similar threads

  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 4 ·
Replies
4
Views
5K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 44 ·
2
Replies
44
Views
5K