Neutrinos: Data, Cosmos, and Planck Scale(Conference)Coordinators: V. Barger, G. Fuller, W. Haxton, B. Kayser, H. Murayama, T. WeilerMarch 3, 2003 - March 7, 2003 |
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Neutrinos have been mystery particles ever since Pauli\'s original proposal. We now have recent and compelling evidence that neutrinos have nonzero mass, from the SuperKamiokande, Sudbury Neutrino Observatory(SNO), K2K, and Kamland experiments. In addition, the mini-BooNE experiment, which should confirm or refute the LSND claim of large Δm2 neutrino oscillations, is now running. However, the present picture of the neutrino mass matrix remains incomplete. Although there have been a number of serious studies of future neutrino factories and more conventional beams, the best strategy to measure θ13, observe possible leptonic CP violation, or involving both particle and nuclear physicists, is needed to provide an implementable strategy for future experiments to complete our understanding. As a part of the future program, it is also important to obtain constraints on neutrino masses and mixings from astrophysical sources and from cosmology. The discussion should include consideration of source dynamics from supernovae, magnetars, gamma-ray bursts, active galactic nuclei, cosmic topological defects and super massive particles, and highly relevant aspects of cosmology such as relic neutrino effects on structure formation and the cosmic energy budget. CP-violating neutrino decay or oscillations may also play a role in producing the cosmological lepton asymmetries, which evolve into the observed baryon excess of our Universe. These astro/cosmo inquiries require interaction between particle, nuclear, and astro-physicists. Finally, information on the neutrino mass matrix impacts deep questions of elementary particle physics, including flavor\'s origin, grand unification, supersymmetry, and extra dimensions. For example, the "seesaw mechanism" explaining the small neutrino masses requires right-handed neutrinos much heavier than the weak-interaction scale. Such a hierarchy calls for supersymmetry. Some other mechanisms to produce small neutrino masses invoke supersymmetry breaking or extra dimensional modeling. It is not understood how neutrino flavor is implemented in these models. Two important aspects to discuss are the predictions of Dirac versus Majorana masses, and the comparison of masses and mixings in the neutrino sector with the quark masses and mixings. To summarize, the major topics for this conference are three:
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