94465 - Theoretical Astroparticle Physics

Learning outcomes

At the end of the course the student will acquire a deep understanding of the connection between particle physics and cosmology. They will master i) the theory and phenomenology of neutrinos; ii) the theoretical aspects of dark matter; iii) the origin of the baryon asymmetry in the early Universe; iv) key aspects of the evolution of Universe including Big Bang Nucleosynthesis, the Cosmic Microwave Background radiation and large scale structure formation from a particle physics perspective; and will have a basic knowledge of the theory of gravitational waves and of cosmic rays. They will be able to present these concepts, inscribing them in the context of the Standard Model and beyond, and of the evolution of the Universe, and to apply the theoretical formalism to compute observables in experimentally relevant situations.

Course contents

1. Overview of the course. The interplay between particles and interactions in the Universe. Brief thermal history of the Universe: inflation, thermal bath and particle decoupling, Big Bang nucleosynthesis, hydrogen recombination, equality of matter and radiation, large scale structure formation. The big five in astroparticle physics: neutrino masses and neutrino role in the Early Universe, the dark matter identity, the origin of the baryon asymmetry, high energy cosmic rays, gravitational waves.

2. Neutrino physics. Neutrinos in the Standard Model and beyond; Neutrino sources on Earth and in the Universe; Neutrino oscillations: Theory, brief overview of experiments, present knowledge of neutrinos and questions for the future; Nature of neutrinos: Majorana versus Dirac particles, Neutrinoless double beta decay; Brief discussion of the origin of neutrino masses beyond the Standard Model. Neutrinos in the Early Universe.

3. Dark Matter. Observational evidence: Rotation curves of galaxies, Virial Theorem in Galaxy Clusters, Cosmology; Dark matter production in the Early Universe: thermal equilibrium and freeze out, relic density, hot and cold dark matter, the WIMP paradigm, non-thermal production mechanisms; Dark Matter Identity: candidates in extensions of the Standard Model, WIMPs, axions, sterile neutrinos and other warm dark matter candidates, other options; Dark Matter Searches at different mass scales: Direct and indirect detection experiments, dark matter at colliders and the intensity frontier.

4. The matter-antimatter asymmetry. Baryogenesis in extensions of the Standard Model: Sakharov conditions, basic properties of models; Leptogenesis and neutrino mass models; Electroweak baryogengesis; alternative mechanisms.

5. High energy cosmic rays. A basic review of cosmic ray physics and astrophysics, including their sources, propagation and detection.

6. Gravitational waves. General relativity and gravitational waves: review of basic principles, the transverse-traceless gauge and the gravitational wave equation, physical and mathematical description in linearised theory, GW polarisation. GW generation and sources: coalescence of binary systems, rotating neutron stars, black holes, Early Universe phenomena, e.g. inflation and phase transitions. GW interactions with matter and their detection: principles of interferometry, noise theory in measuring instruments, brief review of gravitational wave detectors and their techniques. Multi-messenger astronomy connecting GW with HE cosmic rays and neutrinos.

Readings/Bibliography

Astroparticle physics and cosmology:

E.W. Kolb and M.S. Turner

The Early Universe

Westview Press, 1994

Neutrino physics:

C. Giunti and C. W. Kim,

Fundamentals of Neutrino Physics and Astrophysics

Oxford University Press, USA, 2007

Dark Matter:

Particle Dark Matter: Observations, Models and Searches,

Cambridge University Press, Ed. G. Bertone (2010)

High Energy Cosmic Rays:

M. Spurio

Probes of multimessenger astrophysics: Charged cosmic rays, neutrinos, γ-rays and gravitational waves

[ https://www.springer.com/la/book/9783319968537 ]-

Springer DOI: 10.1007/978-3-319-96854-4

 

Alessandro De Angelis, Mário Pimenta

Introduction to Particle and Astroparticle Physics

Springer (2018)

 

Gravitational waves:

M. Maggiore

Gravitational Waves: Volume 1: Theory and Experiments

Oxford University Press, 2008

 

Teaching methods

Lectures at the blackboard/online (in presence and/or remote), complemented by tutorials and topical seminars

Assessment methods

Oral examination including the presentation of an advanced topic

Teaching tools

Slides (PDF) for specific lectures, web resources for further reading.

Office hours

See the website of Silvia Pascoli