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[en] Recent studies by Sehgal and Hung and Sakurai suggest that neutrino hadron neutral current couplings must lie in one of two allowed regions in coupling parameter space. Their analyses are extended using realistic BNL/sub νμ/ and anti ν/sub μ/ spectra in the elastic ν/sub μ/P (anti ν/sub μ/P) calculations and also constraints imposed by the q²-distributions are studied. Also these results are compared with a variety of gauge models. The Weinberg-Salam and SU(2)/sub L/ x SU(2)/sub R/ x U(1) models fall within one allowed region, while a vectorlike SU(3) x U(1) model and a hybrid SU(2) x U(1) model with a (u,b)/sub R/ doublet fall in the other region

[en] In this talk the author describes the theoretical predictions for proton decay and other baryon number violating processes, emphasizing that there are many models and theories involving baryon number violation and that it is an experimental problem to distinguish between them. The author first reviews the theoretical predictions for the unification mass M/sub X/ and for the weak angle sin²theta/sub W/. It will be seen that the class of models involving an SU₃ x SU₂ x U₁ invariant desert between M/sub W/ and M/sub X/ are strongly favored. The author then turns to baryon number violation. The proton lifetime and branching ratio predictions for the SU₅ and other 3-2-1 desert models are reviewed, with emphasis on distinguishing between models and on the implications of the small value of the QCD parameter Λ/sub MS/ that seems to be favored by the data. The author then discusses the consequences of low energy supersymmetry for proton decay, nuclear effects, and models with low mass scales. Finally, he briefly mentions several other topics, including the possibility of observing baryon number violation at accelerators, baryon number violation induced by magnetic monopoles, the violation of Lorentz invariance in proton decay, and antiproton cosmic rays

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[en] In this talk I survey the theoretical expectations for baryon number violation within the context of grand unified theories. I first give a classification of many of the possible baryon-number violating effective operators, including a discussion of typical processes that they induce, their selection rules, their relevant mass scales, and typical underlying mechanisms. I then specialize to the dimension-six four-fermion operators that describe the exchange of lepto-quark diquark bosons in many popular models such as SU₅, SO₁₀, E₆, etc. After describing the general structure of these operators I discuss the estimate of the unification mass, the predictions for the nucleon lifetime, predictions for the branching ratios, and nuclear effects. Special emphasis is given to the related questions of which results are common to a wide class of theories and which types of measurements could discriminate between models

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