Neutrino physics and astrophysics (theory)
Walter Winter (lecture) and Pavlo Plotko (tutorials)
WS 2021/22

Proposed contents (subject to adjustments):

Part I - before Christmas (roughly Oct. 18-Dec. 17)

1)    Neutrino oscillations (theory)

a)    Neutrino oscillations in vacuum

i) Standard derivation of oscillation formula (for arbitrary number of flavours)
ii) Two-flavour limit
iii) Standard three-flavour neutrino oscillations
iv) Simplified three-flavour picture, decoupling limits (solar, atmospheric, reactor)
v)  The hunt for CP violation
vi) Sterile neutrinos
vii) Limitations of standard approach

b)     Neutrino oscillations in matter

i) Hamiltonian in flavour space
ii) Two flavours, constant matter density
iii) Varying matter density (MSW effect), application to Sun
iv) Matter density profiles with jumps (e.g. Earth, supernovae)

2)    Origin of neutrino masses and mixings

a)    Fermion masses in the Standard Model - a recap

i) How do mass terms look like (in the equations of motion)?
ii) Mass terms in the Lagrangian
iii) Mass generation through spontaneous symmetry breaking
iv) Fermion masses in the SM

b)    Massive neutrinos

i) Are neutrino masses physics BSM?
ii) Role of Majorana mass terms
iii) The seesaw mechanism
iv) Origin of lepton mixings and UPMNS
v) Origin of structure/flavour symmetries
vi) Neutrino mass from SM effective field theory
vii) Origin of leptonic CP violation?

c)    Neutrinoless double beta decay

i) Motivation
ii) Phenomenology
iii) Comparison of absolute mass measurement observables
iv) Theoretical interpretation of neutrinoless double beta decay

d)    Principles of baryogenesis/leptogenesis

i) Motivation
ii) Sakharov conditions
iii) Sphaleron processes, leptogenesis
iv) Thermal leptogenesis
v) Alternative mechanisms

Part II - after Christmas (roughly Jan 3-Feb. 18)

3)    Neutrinos from astrophysical accelerators - multi-messenger astrophysics

a)    General overview: Cosmic-ray and neutrino sources

i) Particle acceleration
ii) Astrophysical environments
iii) A toy model for a neutrino-cosmic-ray-source

b)    Description of the radiation zone

i) Kinetic equations
ii) Steady state, general solution
iii) Examples/applications

(1)    Particle leaves region (escapes)
(2)    Origin of spectral breaks
(3)    Cooling of secondaries (muons, pions, kaons) leading to neutrino production

c)    Particle interactions in hadronic sources

i) Generic framework
ii) Weak decays
iii) pp interactions
iv)  Photohadronic interactions (p/A)
v) Simplified pgamma interactions
vi) Multi-messenger relationships
vii) Optically thick case

d)    Gamma-ray bursts as astrophysical test case

i) Internal shock model
ii) Geometry estimators, radiation density
iii) Pion production efficiency
iv) From shock rest frame to the observer’s frame

Note that parts I and II can be in principle independently followed if there is no credit point requirement!

Credit point requirements (6 ECTS, HUB) - needed for Master students:

Participation in bi-weekly tutorials (50% of points required)
Oral examination
Reading assignment, presented in short talk at end of semester

Literature:

Royal Swedish Academy of Science. The Nobel prize in physics 2015. Scientific background: neutrino oscillations
Carlo Giunti and Chung Kim. Fundamental of neutrino physics and astrophysics. Oxford
Martin Pohl. Einführung in die Hochenergieastrophysik. Shaker
Gaisser, Engel and Resconi. Cosmic rays and particle physics. Cambridge
Malcolm Longair. High-energy astrophysics, vol. 1 (particles, photons and their detection). Cambdrige
Walter Winter. Neutrinos from Cosmic Accelerators including Magnetic Field and Flavor Effects, Adv. High Energy Phys. (2012) 586413