A guaranteed source of neutrinos is the production in cosmic ray interactions with the interstellar matter in our Galaxy. The signal has never been detected however and only an upper limit on this... Show moreA guaranteed source of neutrinos is the production in cosmic ray interactions with the interstellar matter in our Galaxy. The signal has never been detected however and only an upper limit on this flux of neutrinos has been published by the AMANDA-II detector. The ANTARES neutrino telescope, located in the Mediterranean Sea, offers a high visibility of the central region of the Milky Way, from where the highest signal is expected. ANTARES data from 2007-2012 were used to compare the flux from a region extending 39 degrees in Galactic longitude and 4.5 degrees in Galactic latitude on either side of the Galactic centre, with the flux from multiple equivalent off-source regions. No significant excess has been observed, and upper limits have been placed on the neutrino flux. The flux limits produced with ANTARES are more than a factor of 10 above the model predictions, which means that a bigger neutrino telescope is needed to constrain the models further. The future KM3NeT telescope is well suited to perform this measurement. Simulations show that by using all neutrinos flavours, KM3NeT should be able to seriously constrain the neutrino flux after about 3 years of operation. Show less
The Standard Model of Particle Physics has many (19) free parameters, most of which (13) are related to the masses and mixing angles of the elementary fermions (quarks and leptons). If we include... Show moreThe Standard Model of Particle Physics has many (19) free parameters, most of which (13) are related to the masses and mixing angles of the elementary fermions (quarks and leptons). If we include neutrino masses, even 22 of the 28 parameters are related to the fermion mass sector. Although these parameters can in principle be completely random, there seems to be a lot of structure here: highly hierarchical masses for the quarks and charged leptons and very peculiar mixing angles for the neutrinos. We can use family symmetries to explain this structure. In models with family symmetry, there is not only the (gauge) symmetry between the types of particles, but also a symmetry between the different families. In this thesis, we consider several model building applications of family symmetries Show less
