Scope of the meeting
Neutrino physics is presently progressing very fast. It is the only field where we have clear indications that one needs to extend the Standard Model of the electroweak and strong interactions beyond massless neutrinos. The Erice school on neutrino physics intents to review the latest status of the field and show its prospects. In detail, the following topics will be presented and discussed:
- properties of neutrinos
- neutrinos and Grand Unification
- the origin of the neutrino mass
- Majorana versus Dirac neutrinos
- the hierarchy problem
- CP violation in the neutrino sector and the mixing angle ϑ13
- neutrino oscillations
- determination of the Majorana phases
- neutrino mass from beta decay
- double beta decay and neutrino mass
- double beta decay and physics beyond the standard model
- neutrinos and cosmology
- neutrinos in supernovae
- solar neutrinos
- long-base-line neutrino experiments
- neutrino factories
Our goal is to elucidate the status and the open questions in the field, such as: Are neutrinos Dirac or Majorana particles? What is the absolute mass scale of the neutrinos? How large is the mixing angle ϑ13? Do neutrino oscillations violate CP invariance? What is the value of the CP violating Dirac phase δ? Can one improve the determination of mixing angles and mass-squared differences from theoretical interpretations of the next generation of precision neutrino-oscillation studies? What is the best way to distinguish between the normal or the inverted mass hierarchy?
Other important issues involve the determination of the Majorana phases and the feasibility of such experiments. The crucial experiment to distinguish between Dirac and Majorana neutrinos is the neutrinoless double beta decay (0νββ), possible only for Majorana neutrinos. The 0νββ determines an absolute mass scale for neutrinos, if light neutrino exchange is the leading contribution and the nuclear matrix elements can be reliably determined. Are there observables, which allow to pin down the leading contribution for the 0νββ decay (for example, light- or heavy-neutrino exchange, right-handed currents, heavy vector bosons in left-right symmetric unified models, contributions from supersymmetry)?
Last, but not least, neutrinos are an important probe of the cosmic evolution, possibly down to the earliest moments of the evolution of the universe in the Big Bang, where the observed baryon asymmetry was generated, for example through the leptogenesis mechanism. The study of neutrinos from supernova explosions, pulsars and high-energy sources may shed further light on the basic role of neutrinos in the Universe.
The workshop will deal with questions such as: what is the origin of neutrino masses? Why are they so small?
Are there extensions of the standard model based on flavor symmetries embedded in unified or/and supersymmetric models, which lead to an understanding of neutrino properties? What is the impact of neutrino mass generation on electroweak symmetry breaking? Are there extra dimensions? This requires not only "theoretical interpretation" but also a dedicated effort to unravel neutrino properties from all sources of information, confronting the results with theoretical models, and studying the implications for astrophysics and cosmology. These are the central scientific issues to be addressed in this workshop. Speakers of the workshop will discuss how to "reconstruct" the mass matrix from all relevant data and hence get information on the basic underlying theory. Progress can only be made in close contact between theory and the ongoing experimental effort, with especial strategic emphasis on those experiments. Thus the workshop offers talks of leading experimentalists in this field. On the other hand, there is a variety of different technologies, currently envisaged for the study of neutrinos, including not only conventional neutrino beams, wide-band beams, super beams and beta beams, in addition to radioactive sources. Therefore the workshop will also include a presentation on neutrino factories.
