Cross sections with polarized spin-1/2 particles in terms of helicity amplitudes
The derivation of cross sections for collisions with polarized particles of spin 1/2 can be simplified considerably if the scattering amplitude is calculated explicitly before the transition probability is obtained by a simple squaring. The states of the polarized particles are represented as superpositions of states with definite helicity. The coefficients of the superposition relate directly to the strength of the transversal and longitudinal polarization. The helicity amplitudes are products of helicity currents for which detailed formulas have been elaborated. Two-component spinors have been used. All the contractions of vector indices are done with a new set of general formulas. The resulting cross sections show terms with separate factors due to the polarization, the energy, and the directions of the particles. Therefore, the high energy approximation can be achieved very conveniently. Applications of the described method have been performed to the scattering of electrons by electrons or positrons including the exchange of Z/sub 0/ and Higgs particles.
- Research Organization:
- Sektion Physik, Universitaet Muenchen, Munich, West Germany
- OSTI ID:
- 5576745
- Journal Information:
- J. Math. Phys. (N.Y.); (United States), Journal Name: J. Math. Phys. (N.Y.); (United States) Vol. 24:12; ISSN JMAPA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
645500* -- High Energy Physics-- Scattering Theory-- (-1987)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
AMPLITUDES
CHARGED PARTICLES
COLLISIONS
CROSS SECTIONS
ELECTRODYNAMICS
ELECTRON COLLISIONS
ELECTRON-ELECTRON COLLISIONS
ELECTRON-POSITRON COLLISIONS
FIELD THEORIES
HELICITY
ORIENTATION
PARTICLE PROPERTIES
POSITRON COLLISIONS
QUANTUM ELECTRODYNAMICS
QUANTUM FIELD THEORY
SCATTERING
SCATTERING AMPLITUDES
SPIN ORIENTATION
USES