Book contents
- Frontmatter
- Contents
- Preface
- Acknowledgements
- Notational conventions
- Errata
- 1 Spin and helicity
- 2 The effect of Lorentz and discrete transformations on helicity states, fields and wave functions
- 3 The spin density matrix
- 4 Transition amplitudes
- 5 The observables of a reaction
- 6 The production of polarized hadrons
- 7 The production of polarized e±
- 8 Analysis of polarized states: polarimetry
- 9 Electroweak interactions
- 10 Quantum chromodynamics: spin in the world of massless partons
- 11 The spin of the nucleon: polarized deep inelastic scattering
- 12 Two-spin and parity-violating single-spin asymmetries at large scale
- 13 One-particle inclusive transverse single-spin asymmetries
- 14 Elastic scattering at high energies
- Appendix 1 The irreducible representation matrices for the rotation group and the rotation functions djλμ(θ)
- Appendix 2 Homogeneous Lorentz transformations and their representations
- Appendix 3 Spin properties of fields and wave equations
- Appendix 4 Transversity amplitudes
- Appendix 5 Common notations for helicity amplitudes
- Appendix 6 The coefficients involved in the parity-invariance relations amongst the dynamical reaction parameters
- Appendix 7 The coefficients involved in the additional invariance constraints on the dynamical reaction parameters for a spin-s particle
- Appendix 8 Symmetry properties of the Cartesian reaction parameters
- Appendix 9 ‘Shorthand’ notation and nomenclature for the Argonne Lab reaction parameters
- Appendix 10 The linearly independent reaction parameters for various reactions and their relation to the helicity amplitudes
- Appendix 11 The Feynman rules for QCD
- Appendix 12 Dirac spinors and matrix elements
- References
- Index
9 - Electroweak interactions
Published online by Cambridge University Press: 13 January 2010
- Frontmatter
- Contents
- Preface
- Acknowledgements
- Notational conventions
- Errata
- 1 Spin and helicity
- 2 The effect of Lorentz and discrete transformations on helicity states, fields and wave functions
- 3 The spin density matrix
- 4 Transition amplitudes
- 5 The observables of a reaction
- 6 The production of polarized hadrons
- 7 The production of polarized e±
- 8 Analysis of polarized states: polarimetry
- 9 Electroweak interactions
- 10 Quantum chromodynamics: spin in the world of massless partons
- 11 The spin of the nucleon: polarized deep inelastic scattering
- 12 Two-spin and parity-violating single-spin asymmetries at large scale
- 13 One-particle inclusive transverse single-spin asymmetries
- 14 Elastic scattering at high energies
- Appendix 1 The irreducible representation matrices for the rotation group and the rotation functions djλμ(θ)
- Appendix 2 Homogeneous Lorentz transformations and their representations
- Appendix 3 Spin properties of fields and wave equations
- Appendix 4 Transversity amplitudes
- Appendix 5 Common notations for helicity amplitudes
- Appendix 6 The coefficients involved in the parity-invariance relations amongst the dynamical reaction parameters
- Appendix 7 The coefficients involved in the additional invariance constraints on the dynamical reaction parameters for a spin-s particle
- Appendix 8 Symmetry properties of the Cartesian reaction parameters
- Appendix 9 ‘Shorthand’ notation and nomenclature for the Argonne Lab reaction parameters
- Appendix 10 The linearly independent reaction parameters for various reactions and their relation to the helicity amplitudes
- Appendix 11 The Feynman rules for QCD
- Appendix 12 Dirac spinors and matrix elements
- References
- Index
Summary
One of the most dramatic events in the history of elementary particle physics was the unification of the electromagnetic and the weak interactions into a single, beautiful gauge theory, which was created by Weinberg, Salam and Glashow and which is nowadays referred to as the ‘Standard Model’ (SM). For a detailed pedagogical account of the need for and development of such a theory, the reader is referred to Leader and Predazzi (1996). We simply recall that this tightly knit theory contains the astounding and incredible prediction of the existence of a set of three vector bosons, W±, Z0, with huge masses, mw ≈ 80 GeV/c2, mz ≈ 90 GeV/c2, and that these unlikely objects were eventually discovered. (The W was identified at CERN in January 1983 and the Z0, also at CERN, a few months later.) A test for the spin of the W is described in subsection 8.2.1(ix).
In the Standard Model the electroweak interactions are mediated by the exchange of photons, Zs and Ws, whose coupling to the basic fermions (leptons and quarks) is a mixture of vector and axial-vector. To begin with all particles are massless, and their masses are generated by spontaneous symmetry breaking. The usual mechanism of symmetry breaking requires a neutral scalar particle, the Higgs meson H, whose mass is not determined by the theory. H has not yet been detected experimentally and is the most serious missing link in the theory. But in every other respect the theory has been remarkably successful.
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- Spin in Particle Physics , pp. 234 - 257Publisher: Cambridge University PressPrint publication year: 2001