Rep. Prog. Phys. 49 (1986)61-105. Printed in Great Britain
Applied supersymmetry and supergravity
D V Nanopoulos CERN,CH-1211 Geneva 23, Switzerland
Abstract
In this review I discuss in some detail the structure and physical consequences of global and local supersymmetric (SUSY) gauge theories. Section 1 contains motivations for SUSY theories, whilst §§ 2 and 3 explain what supersymmetry is, and what are its physical properties. The observable consequences of SUSY at low energies and super- high energies are discussed in §§ 4 and 5. The physical structure of simple (N= 1) local SUSY (= supergravity) is given in § 6, whilst § 7 contains the physics of simple supergravity both at superhigh as well as at low energies. The experimental evidence (?) for supersymmetry is analysed in § 8, whilst § 9 contains the conclusions. Amazingly enough, we find that gravitational effects, as contained in supergravity theories, may play a rather fundamental role at all energy scales. This strong interrelation between gravity and particle physics is unprecedented.
This review was received in November 1984.
0034-4885/86/010061+ 45$09.00 @ 1986 The Institute of Physics 61 62 D V Nanopoulos
Contents Page 1. Motivation(s) for supersymmetry 63 2. Supersymmetry (SUSY) 65 3. Physical properties of supersymmetry 67 4. ‘Low energy’ physics and SUSY 73 5. Supersymmetric GUTS 75 6. Physical structure of simple (N= 1) supergravity 79 7. Physics with simple (N= 1) supergravity 86 7.1. Physics around the GUT scale (Mx) 86 7.2. Physics around the electroweak scale (Mw) 89 7.3. No-scale models 92 8. Experimental evidence (?) for supersymmetry 97 9. Conclusions 101 References ’ 102 Applied supersymmetry and supergravity 63
1. Motivation(§) for supersymmetry
Unification of all elementary particle forces has been the holy grail of theoretical physics. The first realistic step towards this end has been the highly successful unification between electromagnetic and weak interactions, now called electroweak interactions. The obvious (and natural) next step is then the amalgamation of electro- weak and strong interactions, justifiably called grand unified theories (GUTS). (For reviews on GUTS see e.g. Ellis 1984, Nanopoulos 1980, Langacker 1981.) The qualitative successes (e.g. charge quantisation, equality of diff erent coupling constants and equality of certain quark-lepton masses at superhigh energies, natural understanding of quark and lepton quantum numbers, etc), as well as the quantitative successes (e.g. disparity of coupling constants and of quark-lepton masses at low energies, determination of the electroweak mixing angle ( eEW),possible limit on the number of flavours, virtually massless neutrinos, etc) are rather well known (Ellis 1984, Nanopoulos 1980, Langacker 1981). It is also well known that the grand unification scale Mxis rather large
Mx- lOI5 GeV. (1.1)
GUTS contain baryon and lepton number violating interactions, and the presently observed proton stability (rP> 1031-1032yr) immediately puts a lower bound on Mx which more or less is saturated by (1.1). The existence of two scales, the electroweak scale (Mw- 100 GeV) and the GUT scale M,, so different