# What is chirality?

I actually wanted to make the title as "What is the difference between chirality and helicity"? But I didn't do that because I don't understand properly what chirality is.

I have gone through this Wikipedia article: chirality to get the meaning of chirality? and what I get from there is that something is said to have chirality if it is not identical to its mirror image.

But I have often seen people saying a massless particle have same helicity (handedness, I think) and chirality? Now if the chirality has the above defination then how do people say it?

Again for massive particle we can have changed helicity by changing our reference frame. Ok I understand that, but How does it have anything to compare with chirality?

I have read these: Helicity and Chirality and many others in this site. But didn't find(or maybe didn't understand) the answer there which I am looking for.

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It would be easier if you told us your background. Do you know the Lorentz group, Dirac equation, special relativity... Do you understand that helicity is the projection of spin in the direction of momentum? –  jinawee May 25 at 20:05
@jinawee, I don't know group well,but know Lorentz transformation and all the other things that you have asked. –  user22180 May 25 at 20:56
@jinawee,As I don't know the group well, it may be one of the reason I am having the question. If this case can you please suggest some reference from where I can get some working knowledge of group to understand chirality. –  user22180 May 25 at 21:04
Here is a PDF comparing & contrasting the two concepts. This is part of a larger book that can be found here. –  BMS May 25 at 21:09