Dark Matter Through ALP Portal: An Introduction

Table of Links

Acknowledgements

1 Introduction to thesis

1.1 History and Evidence

1.2 Facts on dark matter

1.3 Candidates to dark matter

1.4 Dark matter detection

1.5 Outline of the thesis

2 Dark matter through ALP portal and 2.1 Introduction

2.2 Model

2.3 Existing constraints on ALP parameter space

2.4 Dark matter analysis

2.5 Summary

3 A two component dark matter model in a generic 𝑈(1)𝑋 extension of SM and 3.1 Introduction

3.2 Model

3.3 Theoretical and experimental constraints

3.4 Phenomenology of dark matter

3.5 Relic density dependence on 𝑈(1)𝑋 charge 𝑥𝐻

3.6 Summary

4 A pseudo-scalar dark matter case in 𝑈(1)𝑋 extension of SM and 4.1 Introduction

4.2 Model

4.3 Theoretical and experimental constraints

4.4 Dark Matter analysis

4.5 Summary

5 Summary

Appendices

A Standard model

B Friedmann equations

C Type I seasaw mechanism

D Feynman diagrams in two-component DM model

Bibliography

2 Dark matter through ALP portal

This chapter deals with fermion dark matter interacting with SM via the ALP portal. The results are based on the work: Shivam Gola, Sanjoy Mondal, and Nita Sinha, “ALP portal majorana dark matter, Int.J.Mod.Phys.A 37 (2022) 22, 2250131”.

2.1 Introduction

The discovery of neutrino oscillations confirming the existence of at least two nonvanishing neutrino mass-squared differences necessitates physics beyond the Standard Model (BSM). In principle, neutrino mass could be simply generated by the addition of right-handed neutrinos (RHNs) to the SM particle content. These RHNs interact with SM fields via mixing with active neutrinos. Since RHNs are SM singlets, they allow the Majorana mass term along with the usual Dirac mass term. This is known as type-I seesaw mechanism [71–74]. The mass of these RHNs could range from eV to GUT scale, depending on the models [75–78]. RHNs can also play the role of warm dark matter (WDM), which is singlet under the SM gauge symmetry and has tiny mixing with the SM neutrinos, leading to a long lifetime [79–81]. Also, KeV-scale RHN has been studied as a viable DM candidate [82–84]. In this work, we have instead focused on the prospects of having GeV-scale RHNs as WIMP DM candidates.

Chapter 2 is organised as follows: In Sec. 2.2, we introduced our model, detailing the new interactions present. In Sec. 2.3, we summarise the existing constraints on ALP parameter space coming from various observable and collider searches. In Sec. 4.4, we have explored and discussed the feasible parameter space coming from DM analyses, such as relic density and direct and indirect detection. Finally, we give our summary in Sec. 2.5.