Implications of CHOOZ results for the decoupling of solar and atmospheric neutrino oscillations

We have considered the results of solar and atmospheric neutrino oscillation experiments in the scheme of mixing of three neutrinos with a mass hierarchy. It is shown that the recent results of the CHOOZ experiment imply that |U_{e3}|^2<<1 (U is the neutrino mixing matrix), that the oscillations of solar neutrinos are described by the two-generation formalism and that the oscillations of solar and atmospheric neutrinos decouple. It is also shown that if not only |U_{e3}|^2<<1 but also |U_{e3}|<<1, then the oscillations of atmospheric neutrinos do not depend on matter effects and are described by the two-generation formalism. In this case, with an appropriate identification of the mixing parameters, the two-generation analyses of solar and atmospheric neutrino data provide direct information on the mixing parameters of three neutrinos. We discuss the possibility to get information on |U_{e3}|^2 in long-baseline neutrino oscillation experiments.Comment: 12 pages, no figure

Is bi-maximal mixing compatible with the large angle MSW solution of the solar neutrino problem?

It is shown that the large angle MSW solution of the solar neutrino problem with a bi-maximal neutrino mixing matrix implies an energy-independent suppression of the solar nu_e flux. The present solar neutrino data exclude this solution of the solar neutrino problem at 99.6% CL.Comment: 6 pages. No figure

The Oscillation Probability of GeV Solar Neutrinos of All Active Species

In this paper, I address the oscillation probability of O(GeV) neutrinos of all active flavours produced inside the Sun and detected at the Earth. Flavours other than electron-type neutrinos may be produced, for example, by the annihilation of WIMPs which may be trapped inside the Sun. In the GeV energy regime, matter effects are important both for the ``1-3'' system and the ``1-2'' system, and for different neutrino mass hierarchies. A numerical scan of the multidimensional three-flavour parameter space is performed, ``inspired'' by the current experimental situation. One important result is that, in the three-flavour oscillation case, P{alpha,beta} is different from P{beta,alpha} for a significant portion of the parameter space, even if there is no CP-violating phase in the MNS matrix. Furthermore, P{mu,mu} has a significantly different behaviour from P{tau,tau}, which may affect expectations for the number of events detected at large neutrino telescopes.Comment: 38 pages, 10 figure

The infection of primary avian tracheal epithelial cells with infectious bronchitis virus

Here we introduce a culture system for the isolation, passaging and amplification of avian tracheal epithelial (ATE) cells. The ATE medium, which contains chicken embryo extract and fetal bovine serum, supports the growth of ciliated cells, goblet cells and basal cells from chicken tracheas on fibronectin- or matrigel-coated dishes. Non-epithelial cells make up less than 10% of the total population. We further show that ATE cells support the replication and spread of infectious bronchitis virus (IBV). Interestingly, immunocytostaining revealed that basal cells are resistant to IBV infection. We also demonstrate that glycosaminoglycan had no effect on infection of the cells by IBV. Taken together, these findings suggest that primary ATE cells provide a novel cell culture system for the amplification of IBV and the in vitro characterization of viral cytopathogenesis

Possible tests of neutrino maximal mixing and comments on matter effects

We show in a simple and general way that matter effects do not contribute to the averaged value of the probabilities of transition of solar $\nu_e$'s into other states in the case of maximal mixing of any number of massive neutrinos. We also show that future solar neutrino experiments (Super-Kamiokande and SNO) will allow to test the model with maximal mixing of three massive neutrinos in a way that does not depend on the initial solar neutrino flux.Comment: RevTeX file, 11 pages including 1 figure. The postscript file is available at http://www.to.infn.it/teorici/giunti/papers.htm

Matter effects and CP violating neutrino oscillations with non-decoupling heavy neutrinos

The evolution equation for active and sterile neutrinos propagating in general anisotropic or polarized background environment is found and solved for a special case when heavy neutrinos do not decouple, resulting in non-unitary mixing among light neutrino states. Then new CP violating neutrino oscillation effects appear. In contrast to the standard unitary neutrino oscillations these effects can be visible even for two flavour neutrino transitions and even if one of the elements of the neutrino mixing matrix is equal to zero. They do not necessarily vanish with $\delta m^{2} \to 0$ and they are different for various pairs of flavour neutrino transitions ($\nu_e \to \nu_\mu$), ($\nu_\mu \to \nu_\tau$), ($\nu_\tau \to \nu_e$). Neutrino oscillations in vacuum and Earth's matter are calculated for some fixed baseline experiments and a comparison between unitary and non-unitary oscillations are presented. It is shown, taking into account the present experimental constraints, that heavy neutrino states can affect CP and T asymmetries. This is especially true in the case of $\nu_\mu \to \nu_\tau$ oscillations.Comment: 18 pages, 6 fig

Asymbiotic germination of immature seeds, plantlet development and ex vitro establishment of plants of Dendrobium tosaense Makino - A medicinally important orchid

Shi-hu (Dendrobium spp. or Dendrobii Herba) is one of the important traditional Chinese medicines. The commercially available crude drug in the traditional medicine market is composed mainly of three species: Dendrobium tosaense, D. nobile, and D. moniliforme. An efficient method of propagation has been developed via asymbiotic germination of seeds in vitro for the medicinally important D. tosaense. Seeds from capsules of D. tosaense collected 8-14 wk after artificial pollination germinated after being cultured on full-strength or half-strength Murashige and Skoog (MS) medium devoid of plant growth regulators and with 3% sucrose. Germination of seeds varied with the medium type and seed maturity. Germinated seedlings after transfer to MS medium with 1.5% sucrose and 8% banana homogenate or potato juice or coconut water and 20 wk of incubation developed into healthy plantlets. Well-developed plantlets were transplanted to moss or moss and tree fern or tree fern as substrates in plastic trays and transferred to a greenhouse for hardening. All plants survived, attained maturity, and developed normal flower and capsule after one and a half years. This protocol of successful plant regeneration by asymbiotic seed germination should permit rapid propagation and conservation of this medicinally important Dendrobium species

Neutrino Oscillations in the Framework of Three-Generation Mixings with Mass Hierarchy

We have analyzed the results of reactor and accelerator neutrino oscillation experiments in the framework of a general model with mixing of three neutrino fields and a neutrino mass hierarchy that can accommodate the results of the solar neutrino experiments. It is shown that $\nu_\mu \leftrightarrows \nu_e$ oscillations with $0.6 \le \Delta m^2 \le 100 \, \mathrm{eV}^2$ and amplitude larger than $2 \times 10^{-3}$ are not compatible with the existing limits on neutrino oscillations if the non-diagonal elements of the mixing matrix $\left| U_{e3} \right|$ and $\left| U_{\mu3} \right|$ are small. Thus, if the excess of electron events recently observed in the LSND experiment is due to $\nu_\mu \leftrightarrows \nu_e$ oscillations, the mixing in the lepton sector is basically different from the CKM mixing of quarks. If this type of mixing is realized in nature, the observation of $\nu_\mu \leftrightarrows \nu_e$ oscillations would not influence $\nu_\mu \leftrightarrows \nu_\tau$ oscillations that are being searched for in the CHORUS and NOMAD experiments.Comment: Revtex file, 13 pages + 2 figures (included). The postscript file of text and figures is available at http://www.to.infn.it/teorici/giunti/papers.html or ftp://ftp.to.infn.it/pub/giunti/1995/dftt-25-95/dftt-25-95.ps.

Model Independent Information On Solar Neutrino Oscillations

We present the results of a Bayesian analysis of solar neutrino data in terms of nu_e->nu_{mu,tau} oscillations, independent from the Standard Solar Model predictions for the solar neutrino fluxes. We show that such a model independent analysis allows to constraint the values of the neutrino mixing parameters in limited regions around the usual SMA, LMA, LOW and VO regions. Furthermore, there is a strong indication in favor of large neutrino mixing and large values of Delta m^2 (LMA region). We calculate also the allowed ranges of the neutrino fluxes and we show that they are in good agreement with the Standard Solar Model prediction. In particular, the ratio of the 8B flux with its Standard Solar Model prediction is constrained in the interval [0.45,1.42] with 99.73% probability. Finally, we show that the hypothesis of no neutrino oscillations is strongly disfavored in a model independent way with respect to the hypothesis of neutrino oscillations.Comment: 40 pages, 20 figures. Added references and improved figure