What is particle spin , and does it have anything to do with radio activity?

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Discussion Overview

The discussion focuses on the concept of particle spin, its intrinsic nature, and its potential relation to radioactivity. Participants explore the definitions and implications of spin in quantum mechanics, as well as its distinction from classical notions of spin and angular momentum.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants describe spin as an intrinsic property of particles, akin to mass, while others emphasize its role as intrinsic angular momentum separate from orbital motion.
  • One participant suggests that spin has no direct connection to radioactivity, while another mentions isospin as potentially relevant but does not elaborate.
  • There is a discussion about the difference between integer and half-integer spin, with implications for particle behavior, such as the classification of particles into bosons and fermions based on their spin values.
  • Some participants note that the analogy of spin with classical rotation is limited and that quantum spin involves relativistic elements, affecting how particles behave under transformations.
  • Mathematical expressions related to spin, such as the relationship between spin quantum number and angular momentum, are mentioned, but with varying degrees of confidence among participants.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between particle spin and radioactivity, with no consensus reached. There is also a lack of agreement on the interpretation of spin in relation to classical concepts.

Contextual Notes

Some claims about the nature of spin and its implications are presented with uncertainty, and participants acknowledge potential limitations in their understanding or recall of the subject matter.

Cyberice
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What is particle "spin", and does it have anything to do with radio activity?

I keep hearing about the "spin" of sub-atomic particles like such-and-such particle has a spin of 1/2 or 1. I heard even some have a spin of 2. And it also seems that I have heard that some radioactive particles have a higher spin (or lower - don't remember) than normal. Is this scorce on crack, or can you back-up/explain any of this? I'm just curious.
 
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Spin is a intrinsic property of the particle, like its mass. And it has nothing to do with radioactivity. Isospin, might have somehting to do with radioactivity, but I can't rrecal off the top of my head

JMD
 
Spin is the intrinisic angular momentum of a particle or group of particles, which is in additon to it's angular momntum due to it's orbital motion.

Isopin's a little bit different as it only possesd by hadrons and is always conserved in strong interactions but not electromgnetic interactions.
 
I don't think quantum spin is really the same as spin as we traditionally thing. I think we know it possesses a strong relativistic element, and that the "spin" analogy is sometimes useful, but it is important to remember it isn't the same.

By spin 1 or 0.5, we really mean 1 * hbar or 0.5 * hbar. Whether the particle has integer spin or half-integer spin is very influential on it's behaviour. Integer spin particles (eg. photons) are called bosons, follow the laws know as Bose-Einstein statistics, while half integer spins are called Fermions (eg. electrons) and follow Fermi-Dirac statistics.

If I remember correctly, of course.

EDIT: which I don't, because I am an idiot.

The units of spin are of course in 1/2 * hbar, where hbar = h/(2*pi). Ie a particle with +1 units of spin has really +1 * 0.5 * h/2pi, which preserves the uncertainty principle.

I hope that's right.
 
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Spin is the change of quantum mechanical phase with change of plane angle, and as F.Z. says it has to do with relativity too. Special relativity allows boosts (accelerations) and turns in the three space dimensions, for spin 1/2 states, boosts change the modulus of the amplitude, turns change the phase of the amplitude. The Dirac γ matrices describe these changes.
 
Originally posted by FZ+
I don't think quantum spin is really the same as spin as we traditionally thing. I think we know it possesses a strong relativistic element, and that the "spin" analogy is sometimes useful, but it is important to remember it isn't the same.

By spin 1 or 0.5, we really mean 1 * hbar or 0.5 * hbar. Whether the particle has integer spin or half-integer spin is very influential on it's behaviour. Integer spin particles (eg. photons) are called bosons, follow the laws know as Bose-Einstein statistics, while half integer spins are called Fermions (eg. electrons) and follow Fermi-Dirac statistics.

If I remember correctly, of course.

No it is sort of the same as angular momentum, as I said before tit contributes to the total angular momentum of a particle along with it's orbital angular momentum, though sometimes it is of treated as the particle spinning on it's axis, this is not actually the case it's just an intrinsic property of that particle.

Also spin is actually given by √s(s+1)h/2π, where s is the spin quantum number which is usually a half or an integer.
 

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