Book contents
- Frontmatter
- Contents
- Preface
- 1 The Standard Model and beyond
- 2 Supersymmetry
- 3 Introduction to string theory: the bosonic string
- 4 Superstrings
- 5 Toroidal compactification of superstrings
- 6 Branes and string duality
- 7 Calabi–Yau compactification of heterotic superstrings
- 8 Heterotic string orbifolds and other exact CFT constructions
- 9 Heterotic string compactifications: effective action
- 10 Type IIA orientifolds: intersecting brane worlds
- 11 Type IIB orientifolds
- 12 Type II compactifications: effective action
- 13 String instantons and effective field theory
- 14 Flux compatifications and moduli stabilization
- 15 Moduli stabilization and supersymmetry breaking in string theory
- 16 Further phenomenological properties. Strings and cosmology
- 17 The space of string vacua
- Appendix A Modular functions
- Appendix B Some topological tools
- Appendix C Spectrum and charges of a semi-realistic Z3 heterotic orbifold
- Appendix D Computation of RR tadpoles
- Appendix E CFT toolkit
- Bibliography
- References
- Index
2 - Supersymmetry
Published online by Cambridge University Press: 05 March 2012
- Frontmatter
- Contents
- Preface
- 1 The Standard Model and beyond
- 2 Supersymmetry
- 3 Introduction to string theory: the bosonic string
- 4 Superstrings
- 5 Toroidal compactification of superstrings
- 6 Branes and string duality
- 7 Calabi–Yau compactification of heterotic superstrings
- 8 Heterotic string orbifolds and other exact CFT constructions
- 9 Heterotic string compactifications: effective action
- 10 Type IIA orientifolds: intersecting brane worlds
- 11 Type IIB orientifolds
- 12 Type II compactifications: effective action
- 13 String instantons and effective field theory
- 14 Flux compatifications and moduli stabilization
- 15 Moduli stabilization and supersymmetry breaking in string theory
- 16 Further phenomenological properties. Strings and cosmology
- 17 The space of string vacua
- Appendix A Modular functions
- Appendix B Some topological tools
- Appendix C Spectrum and charges of a semi-realistic Z3 heterotic orbifold
- Appendix D Computation of RR tadpoles
- Appendix E CFT toolkit
- Bibliography
- References
- Index
Summary
Supersymmetry (SUSY) is a symmetry which combines fermions and bosons into the same multiplets. It plays a crucial role in the structure of string theory, and in fact its first appearance as a symmetry in physics arose in trying to extend the bosonic string to include fermions. In string theory, SUSY guarantees the absence of divergences and of tachyonic scalars. Moreover, as discussed in Section 1.3.3, the simplest version of supersymmetry in four dimensions may provide a perturbative solution to the electroweak hierarchy problem, and thus is key to many proposals for physics beyond the Standard Model. For these reasons, most 4d string theory compactifications studied to date are supersymmetric, and lead to SUSY effective theories at low energies.
In this chapter we review general results for 4d N = 1 SUSY and describe its possible role in stabilizing the electroweak scale against radiative corrections. We review local supersymmetry, which leads to the inclusion of gravitation and gives rise to 4d N = 1 supergravity, which may play an important phenomenological role by mediating SUSY breaking. We also introduce the simplest SUSY extension of the SM, the Minimal Supersymmetric Standard Model (MSSM), for reference in future chapters. In addition, we provide a brief introduction to extended SUSY, which includes additional supersymmetry generators; although not of direct interest for particle physics, extended SUSY plays an important role in string theory, and actually appears in intermediate steps in explicit phenomenologically interesting string constructions.
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- Chapter
- Information
- String Theory and Particle PhysicsAn Introduction to String Phenomenology, pp. 25 - 61Publisher: Cambridge University PressPrint publication year: 2012