[aap_]

Very cool! The suggestion to consider how the standard model came to be rather than starting with the result sounds like an excellent idea.

But of course i have to disagree with this: "A spin-1/2 particle is described by a spinor, which is a bit weird, but spin-1 particle is described by something more familiar: a vector!"

In my view a spinor is even more familiar than a vector: it's like a hand - it comes back to itself after 720° of rotation. Just like a vector is like an arrow or a mirror, which come back after 360°. What could be more familiar than a hand?

[frumiousirc]

> it's like a hand - it comes back to itself after 720° of rotation

The analogy is a bit broken in a way that may add confusion. The hand comes back to it's starting configuration after two 360° rotations, each along a different axis. A spinor's symmetry has 720° of rotation along a single axis.

[aap_]

No, around a single axis. if you hold your hand palm up you can rotate in the (vertical) z axis around 360° and get a twist in the arm. another 360° undoes the twist, that's 720° around a single axis.

[frumiousirc]

No. The first rotation is along an axis in the direction in which your fingers point. The second rotation is along an axis normal to your palm.

[aap_]

If you're rotating around your fingers you're doing something else, not what i mean. I'm just talking palm up, rotating in the vertical axis, 720°. like the cup dance.

[gus_massa]

My hand comes back after 360°.

[pavel_lishin]

Attempting to spin my hand by 360° may result in me coming back from the hospital, unless I spin my entire body along with it.

[aap_]

But with a twist in the arm. After another 360 the arm is back too.

[lanza]

> In my view a spinor is even more familiar than a vector

Okay... Pauli and Dirac both received Nobel Prizes for discovering spinors. Nobody needed to discover pointing in some direction.

[aap_]

Sometimes the simplest things are hidden in plain sight :) Most people point with their fingers/hands. Unlike rayman, who has vector-like hands, biological beings have them connected to their body, which makes them behave like spinors. But Dirac actually knew about this, after all there is a belt trick named after him.

[dist-epoch]

"a spinor is like a hand" is about as intuitive as "a monad is like a burrito"

Spinors are so intuitive that you need a 1 hour video full of animations to explain them: https://www.youtube.com/watch?v=b7OIbMCIfs4

[aap_]

The whole assumption of the video is that one cannot understand spinors. He does a good job with the mathematics but i disagree with the premise.