Searching for axions and ALPs from string theory. Andreas Ringwald (DESY) PASCOS 2012, Merida, Mexico, 3-8 June 2012 Particles beyond the Standard Model?! > Standard Model of Particle Physics: Fundamental des- cription of known matter par- ticles and gauge forces Andreas Ringwald | PASCOS 2012 | 3-8 June 2012 | Page 2 Particles beyond the Standard Model?! > Standard Model of Particle Physics: Fundamental des- cription of known matter par- ticles and gauge forces > Standard Model of Cosmolo- gy: only about 5 % of energy content of present universe consists of known particles Andreas Ringwald | PASCOS 2012 | 3-8 June 2012 | Page 3 Particles beyond the Standard Model?! > Standard Model of Particle Physics: Fundamental des- cription of known matter par- ticles and gauge forces > Standard Model of Cosmolo- gy: only about 5 % of energy content of present universe consists of known particles > Extensions of the Standard Model of Particle Physics: several good motivated can- didates for constituents of dark matter  SUSY: Neutralino, Gravitino  Peccei Quinn: Axion Andreas Ringwald | PASCOS 2012 | 3-8 June 2012 | Page 4 Peccei-Quinn extension of the Standard Model > Motivation: Explanation of unnatural smallness, ,, of CP-violating topological term in QCD Lagrangian, > Axion field  Andreas Ringwald | PASCOS 2012 | 3-8 June 2012 | Page 5 Peccei-Quinn extension of the Standard Model > Motivation: Explanation of unnatural smallness, ,, of CP-violating topological term in QCD Lagrangian, > Axion field   Axion: ultralight particle, cf. Weinberg `78; Wilczek `78 Andreas Ringwald | PASCOS 2012 | 3-8 June 2012 | Page 6 Peccei-Quinn extension of the Standard Model > Motivation: Explanation of unnatural smallness, ,, of CP-violating topological term in QCD Lagrangian, > Axion field   Axion: ultralight particle, cf. Weinberg `78; Wilczek `78  extremely weak interactions with Standard Model particles Andreas Ringwald | PASCOS 2012 | 3-8 June 2012 | Page 7 Peccei-Quinn extension of the Standard Model > Motivation: Explanation of unnatural smallness, ,, of CP-violating topological term in QCD Lagrangian, > Axion field   Axion: ultralight particle, cf. Weinberg `78; Wilczek `78  extremely weak interactions with Standard Model particles > Welcome side effect:  Axion: candidate for dark matter: created non-thermally via misa- lignment mechanism in form of coherent oscillations of axion field Andreas Ringwald | PASCOS 2012 | 3-8 June 2012 | Page 8 Coexistence: SUSY and PQ extension in string theory > Particularly strongly motivated extensions of Standard Model based on string theory:  Unification of all forces  Quantum gravity Andreas Ringwald | PASCOS 2012 | 3-8 June 2012 | Page 9 Coexistence: SUSY and PQ extension in string theory > Particularly strongly motivated extensions of Standard Model based on string theory:  Unification of all forces  Quantum gravity > Spectrum of low-energy effec- tive theory in (3+1)-dimensions is supersymmetric and possibly contains several kinds of very weakly interacting slim particles (WISPs): Axion, ALPs (Axion- Like Particles  if the compact space comprised of the 6 extra dimensions has certain geometrical and topological proper- ties (Calabi-Yau; several cycles) Andreas Ringwald | PASCOS 2012 | 3-8 June 2012 | Page 10