This book is about the dark photon which is a new gauge boson whose existence has been conjectured. Due to its interaction with the ordinary, visible photon, such a particle can be experimentally detected via specific signatures. In this book, the authors review the physics of the dark photon from the theoretical and experimental point of view. They discuss the difference between the massive and the massless case, highlighting how the two phenomena arise from the same vector portal between the dark and the visible sector. A review of the cosmological and astrophysical observations is provided, together with the connection to dark matter physics. Then, a perspective on current and future experimental limits on the parameters of the massless and massive dark photon is given, as well as the related bounds on milli-charged fermions. The book is intended for graduate students and young researchers who are embarking on dark photon research, and offers them a clear and up-to-date introduction to the subject.
Author(s): Marco Fabbrichesi, Emidio Gabrielli, Gaia Lanfranchi
Series: SpringerBriefs in Physics
Publisher: Springer
Year: 2020
Language: English
Pages: 88
City: Cham
Preface
Acknowledgements
Contents
1 Introduction
1.1 Massless and Massive Dark Photons
1.1.1 Kinetic Mixing: Electric or Hyper-Charge?
1.1.2 Embedding in a NonAbelian Group
1.2 UV Models
1.2.1 Massive Dark Photon: Origin and Size of the Mixing Parameter
1.2.2 Massless Dark Photon: Higher-Order Operators
1.3 Dark Matter and the Dark Photon
1.3.1 Massless Dark Photon and Galaxy Dynamics
1.3.2 Massless Dark Photon and Dark-Matter Relic Density
1.3.3 Massive Dark Photon and Light Dark Matter
1.3.4 Massive Dark Photon as Dark Matter
References
2 Phenomenology of the Massless Dark Photon
2.1 Limits on the Dark Dipole Scale dM/Λ2
2.1.1 Astrophysics and Cosmology
2.1.2 Precision, Laboratory and Collider Physics
2.1.3 Can the Massless Dark Photon Be Seen at All?
2.2 Limits on Milli-Charged Particles
2.3 A Minimal Model of the Dark Sector
2.3.1 Constraints on the UV Model Parameters
2.4 Future Experiments
References
3 Phenomenology of the Massive Dark Photon
3.1 Production, Decays and Detection
3.2 Visible and Invisible Massive Dark Photon
3.3 Limits on the Parameters ε and mA
3.3.1 Constraints for mA > 1 MeV with A' Decays to Visible Final States
3.3.2 Constraints for mA > 1 MeV with A' Decays to Invisible Final States
3.3.3 Constraints for mA < 1 MeV
3.4 Limits on the Parameters y and mχ
References
4 Outlook
5 Appendix
5.1 Dark Sector Portals
5.2 Boltzmann Equation and Relic Density
5.3 Thermal Field Theory
References
