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A delta ray is a secondary electron with enough energy to escape a significant distance away from the primary radiation beam and produce further ionization. [ 1 ] : 25 The term is sometimes used to describe any recoil particle caused by secondary ionization .
The Delta states discussed here are only the lowest-mass quantum excitations of the proton and neutron. At higher spins , additional higher mass Delta states appear, all defined by having constant 3 / 2 or 1 / 2 isospin (depending on charge), but with spin 3 / 2 , 5 / 2 , 7 / 2 , ..., 11 / 2 ...
It is called the delta function because it is a continuous analogue of the Kronecker delta function, which is usually defined on a discrete domain and takes values 0 and 1. The mathematical rigor of the delta function was disputed until Laurent Schwartz developed the theory of distributions, where it is defined as a linear form acting on functions.
The delta potential is the potential = (), where δ(x) is the Dirac delta function. It is called a delta potential well if λ is negative, and a delta potential barrier if λ is positive. The delta has been defined to occur at the origin for simplicity; a shift in the delta function's argument does not change any of the following results.
These actions are represented in the form of visual shorthand by the three basic elements of diagrams: a wavy line for the photon, a straight line for the electron and a junction of two straight lines and a wavy one for a vertex representing emission or absorption of a photon by an electron. These can all be seen in the adjacent diagram.
Feynman diagram of electron/positron annihilation. The electron–positron annihilation interaction: e + + e − → 2γ. has a contribution from the second order Feynman diagram: In the initial state (at the bottom; early time) there is one electron (e −) and one positron (e +) and in the final state (at the top; late time) there are two ...
The electron spin angular momentum is a fundamentally different property that is intrinsic to the particle and therefore does not depend on the motion of the electron. Nonetheless, it is angular momentum and any angular momentum associated with a charged particle results in a magnetic dipole moment, which is the source of a magnetic field.
In molecular physics, the molecular term symbol is a shorthand expression of the group representation and angular momenta that characterize the state of a molecule, i.e. its electronic quantum state which is an eigenstate of the electronic molecular Hamiltonian.