A Conversation for The Sub-Atomic World of Kaons, Axions, J/Psi, Sigma and Xi Particles.


Post 1


Sorry, but you're wrong about spin.
If a particle has spin 2 it means that if it is rotated through 360 degrees, there are two times in the process that it will be identical to its original state (A sheet of blank A4 paper has this property - if someone rotated a sheet through 180 degrees while you were out of the room, you couldn't tell).
Spin 1 means that only once in a full rotation does the particle come back to its original state (most everyday objects are spin 1).
Spin 1/2 is weird: rotating it through 360 does not bring it back to its original state. It has to be rotated twice (720 degrees) to bring it back to its original state. The only 'everyday' object I know with this property is a Moebius strip, but even then I have it on good authority that this is a different sort of spin. Confused? I was...


Post 2


what a nice way to explain does a photon carrying light also have an anti photon?


Post 3


Yes and no. To quote Stephen Hawking (you didn't think I knew this stuff for myself did you?): 'Every particle has an antiparticle...(In the case of the force-carrying particles (this includes the photon, which carries the electromagnetic force - Ewen), the antiparticles are the same as the particles themselves.)' (A Brief History of Time; p75 in my 1995 Bantam paperback)

Reading through my earlier posting I noticed how rude I was not to compliment Baryonic Being on his/her excellent article. Well, better late than never...


Post 4

Baryonic Being - save GuideML out of a word-processor: A7720562

I'm sorry I have not replied yet... I didn't see this conversation (we are not automatically subscribed to our Edited versions of entries).

You are quite right, Ewen, I have made a monumental mistake!

Am I right about spin 3/2 though?

Can anyone advise me on how to have the entry updated?


Post 5


I'm not sure about editing, Baryonic. I'm one of those who just carps on the sidelines without contributing anything...

Spin 3/2 is (I think) where over the course of two rotations there are three repeats of the original state. I can't think of any everyday analogies.

By my reckoning, spin = number of repeats of original state / number of 360-degree rotations.

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