Talk:Chirality (physics)
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Alterations and restructuring are needed to properly represent use and meaning of the word chirality. Please join the multi-disciplinary discussion on Talk:Chirality. --Cigno 22:12, 15 November 2005 (UTC)
[edit] Merge with Helicity
Two reasons.
- For massless particles, there's no difference between chirality and helicity, except for numerical factor.
- For massive particles, the two are often confused. Even this article talks about "relative chirality, which depends on the observer’s reference frame", but what it really means is that massive particles have relative helicities. As the article correctly says in the section 2, chirality is given by the operator γ5. Chirality is Lorentz-invariant, and helicity is not. --Itinerant1 05:27, 4 September 2006 (UTC)
- If you're an expert on the subject (or have knowledge) by all means please merge. Radagast83 19:58, 28 October 2006 (UTC)
[edit] Don't merge with helicity
- The two quantities are often conflated and, unless expertly done, merging the articles is only likely to encourage this misconception to persist. It may even be worth adding "not to be confused with helicity" or such into the first paragraph of this article, but I don't feel I'm expert enough to draw the appropriate distinction yet.
[edit] Chirality Explained Wrong
Chirality is explained wrong. It is not the projection of the spin in the direction of motion. Helicity is in fact the spin projection on the direction of motion (and therefore depends on the reference frame). Chirality is a much more abstract concept, and it does not depend on the frame of reference. For massless particles (and only for those), chirality and helicity are the same. For massive particles they are different - one independent of the frame of reference, the other not. So, for massless particles, a chirality left-handed particle is always helicity left-handed. But for massive particle, a chirality left-handed particle can be helicity right-handed. See for example pion decay, where this effect (and its dependence on the mass of the particle) plays a major role. It is however true, that parity transforms chirality left-handed particles to chirality right-handed ones, as well has helicity left-handed ones to helicity right-handed ones (and vice versa).