Need help with angular momentum!! Hi - I have been working on this homework problem for 3 days now and I'm so stumped! Any help would be much appreciated! A particles with total angular momentum J = 1 is in an eigenstate |j,m> of the operators J^2, J_z. This problem concerns the probability of finding the particle in an eigenstate |j,m_n> of the operator K(hat) = n (dot) J which is the projection of ang. mom. along n. n = sin(theta)cos(phi) e_x + sin(theta)sin(phi) e_y + cos(theta) e_z ---> spherical polar angles What are allowed values of m_n? How would I go about finding the probability of finding the particle in eigenstate |j,m_n> for any value of m_n when the particle is prepared in the state |j,m=1> where I think j is always 1 for this problem. Thanx!