String and D-brane Physics at Low Energy †

1. Preliminaries. 2. Heterotic string and motivations for large volume compactifications; 2.1 Gauge coupling unification; 2.2 Supersymmetry breaking by compactification. 3. M-theory on S^1/Z_2 \times Calabi-Yau. 4. Type I/I' string theory and D-branes; 4.1 Low-scale strings and extra-large transverse dimensions; 4.2 Relation type I/I' -- heterotic. 5. Type II theories; 5.1 Low-scale IIA strings and tiny coupling; 5.2 Large dimensions in type IIB; 5.3 Relation type II -- heterotic. 6. Theoretical implications; 6.1 U.V./I.R. correspondence; 6.2 Unification ; 6.3 Supersymmetry breaking and scales hierarchy ; 6.4 Electroweak symmetry breaking in TeV-scale strings. 7. Scenarios for studies of experimental constraints. 8. Extra-dimensions along the world brane: KK excitations of gauge bosons; 8.1 Production at hadron colliders; 8.2 High precision data low-energy bounds; 8.3 One extra dimension for other cases; 8.4 More than one extra dimension. 9. Extra-dimensions transverse to the brane world: KK excitations of gravitons; 9.1 Signals from missing energy experiments; 9.2 Gravity modification and sub-millimeter forces. 10. Dimension-eight operators and limits on the string scale. 11. D-brane Standard Model; 11.1 Hypercharge embedding and the weak angle; 11.2 The fate of U(1)'s and proton stability. 12. Appendix: Supersymmetry breaking in type I strings; 12.1 Scherk-Schwarz deformations; 12.2 Brane supersymmetry breaking.