Tag Info

Hot answers tagged

10

Spin is best understood as an intrinsic angular momentum. It is probably easier to understand the concept for a charged particle. A classical charged particle moving along a circle has an angular momentum and the "circuit" has a magnetic moment. Further, the two are proportional to each other. It is experimentally found that a charged particle like an ...


7

The total angular momentum of a meson is the sum of the spins of the two quarks and their orbital angular momentum. Excited states can have $L>0$ and therefore $J>1$.


4

Please let me first refer you to the following review by I. L. Shapiro, which contains a lot of theoretical and phenomenological information on spacetime torsion. The answer will be mainly based on this review. In the basic Einstein-Cartan theory, in which the antisymmetric part of the connection is taken as independent additional degrees of freedom, the ...


3

Spin arises from the need to represent the rotation group $\mathrm{SO}(3)$ upon our Hilbert space of states. We need such a representation because the rotations (together with space translations) correspond to the non-relativistic changes of reference frames. Since states are only determined up to rays in the Hilbert space, the true space of states on which ...


3

As in the comments, because you are initially stationary relative to the Earth's surface, your initial velocity is exactly the same as that of the ground. The reason why is friction and air resistance: if you weren't so (perhaps you'd just dropped in from space, maybe from Betelgeuse Seven to warn Arthur Dent of a disaster in the offing, and you hadn't ...


2

Correction $\Delta(1620) 1/2^-$ is actually pretty well settled. (Thanks to rob.) Original Answer Actually, the Pauli exclusion principle can explain why there are no (uuu,ddd,sss) spin-1/2 ground states. In baryons, quarks have four degree of freedom: orbital, spin, flavor, color. As you already know, the quarks' total wave functions should be ...


2

Spin of an electron is measured as a magnetic property. You should not visualize it as an electron "spinning" around its axis, which is what you seem to indicate if I'm not mistaken. Electrons are considered to be point particles. Also, the spin of an electron never changes instantaneously. For example, changes in the electron's spin in the Stern-Gerlach ...


2

Spin is precisely the number that tells you in which representation of the rotation group $\mathrm{SO}(3)$ (non-relativistic) or Lorentz group $\mathrm{SO}(1,3)$ (relativistic) a quantum state transforms. As these groups are precisely the transformations between reference frames (aside from the boring translations), spin is an invariant under change of ...


1

If the protons are in a spin singlet, the neutron spin determines the spin of the $^3\text{He}$ nucleus. Without loss of generality you can define the direction of the $^3\text{He}$ polarization as $\uparrow$. Under isospin symmetry, the proton and the neutron are two states of the same particle. If your problem includes this symmetry (and if you can assume ...


1

IT's not particularly noticeable when you jump, because you didn't get very high. But if you, say, shoot a model rocket a few hundred meters up, barring interactions w/ the air, it'll land to the west of its launch point. For an analogy, suppose you're in a car going at constant angular speed in a circle of some radius. If you then run right behind the ...


1

I'm trying to give a less technical answer. It's not rigorous but should give you the idea how spin and the regular rotation related. Maxwell's equations say in order to have magnetic field, you need a ring current. This can be achieved by giving angular momentum to charged particles. This can be orbital or simply because the particle is spinning. This was ...


1

First observation of a heavy flavored spin-3 particle http://home.web.cern.ch/scientists/updates/2014/07/first-observation-heavy-flavored-spin-3-particle Discovery of new subatomic particle sheds light on fundamental force of nature http://home.web.cern.ch/scientists/updates/2014/07/first-observation-heavy-flavored-spin-3-particle



Only top voted, non community-wiki answers of a minimum length are eligible