Freiburg 1999 – scientific programme

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HK: Physik der Hadronen und Kerne

HK 5: Kern- und Teilchen- Astrophysik I

HK 5.2: Talk

Monday, March 22, 1999, 14:30–14:45, C

Super-Kamiokande Oscillations and Supersymmetry — •Sergey Kovalenko¹, Amand Faessler¹, and Vadim Bednyakov² — ¹Institut für Theoretische Physik, Universität Tübingen, auf der Morgenstelle 14, 72076 Tübingen — ²Joint Institute for Nuclear Research, Dubna, Russia

The neutrino masses and mixing constitute one of the most pressing problem of particle physics. At present, there is a convincing experimental evidence for a non-trivial structure of the three-generation neutrino mass matrix. It derives from the solar and atmospheric neutrino deficit as well as, likely, from the LSND experiment. All the three types of observations can be explained by (anti)neutrino oscillations. An experimental breakthrough in exploration of the atmospheric neutrino anomaly has been recently made by the Super-Kamiokande collaboration measured the zenith angle dependence of the atmospheric neutrino flux. This experiment confirmed that the most likely solution of the atmospheric neutrino anomaly implies neutrino oscillation preferably in ν_µ → ν_τ channel. We consider the neutrino oscillations within the minimal supersymmetric(SUSY) standard model with the most general case of R-parity violation taking into account the trilinear and the bilinear R-parity violating terms in the superpotential and in the soft SUSY breaking sector. At tree level one finds in this model two massless neutrino states and one massive. Quantum corrections modify this picture, so that the massless states acquire small non-zero masses. The Super-Kamiokande atmospheric neutrino oscillation data set limits on the difference between the squared masses of the two neutrinos and on the mixing angles. This allowed us to derive the stringent constraints on the sneutrino vacuum expectation values ⟨ν_α⟩ and on the lepton-Higgs mixing parameter µ_α:

with the upper row corresponding to α = e and the bottom one corresponding to α = µ, τ. We argue this constraints to have important phenomenological implications.