Amplitudes

Some articles on amplitudes, amplitude:

MHV Amplitudes
... In theoretical particle physics, maximally helicity violating amplitudes are amplitudes with n external gauge bosons, where n-2 gauge bosons have a particular helicity and the other two have the opposite helicity ... These amplitudes are called MHV amplitudes, because at tree level, they violate helicity conservation to the maximum extent possible ... The tree amplitudes in which all gauge bosons have the same helicity or all but one have the same helicity vanish ...
MHV Amplitudes - The Parke–Taylor Amplitudes
... of many gluons, certain classes of amplitude vanish at tree level in particular when fewer than two gluons have negative helicity (and all the rest have positive ... Such amplitudes are known as "maximally helicity violating" and have an extremely simple form in terms of momentum bilinears, independent of the number of gluons present The compactness of ... A rigorous derivation of the Parke-Taylor amplitudes was given by Berends and Giele ...
Atom Vibrations
... waves of different lengths, frequencies, and amplitudes run through crystalline solids at all times ... frequencies is 1013 Hz, and that of the amplitudes is 10-11 m ... The amplitude-frequency characteristics of the vibrating spectrum of an alloy can be varied, for example by alloying, to produce a well-directed effect on the ...
Automatic Calculation Of Particle Interaction Or Decay - Matrix Element Calculation Methods - Helicity Amplitude
... Feynman amplitudes are written in terms of spinor products of wave functions for massless fermions, and then evaluated numerically before the amplitudes are squared ... Taking into account fermion masses implies that Feynman amplitudes are decomposed into vertex amplitudes by splitting the internal lines into wave function of fermions and polarization vectors of gauge bosons ...
Neutron-star Oscillation - Oscillation Excitation
... in neutron stars are probably weak with small amplitudes, but exciting these oscillations might increase the amplitudes to observable levels ... The hit adds energy to the system, which excites the amplitudes of the oscillations to greater magnitude, and so is more easily observed ...