16,614 research outputs found
Reconstruction of the Neutrino Mixing Matrix and Leptonic Unitarity Triangles from Long-baseline Neutrino Oscillations
We derive a new set of sum rules between the neutrino mass and mixing
parameters in vacuum and their effective counterparts in matter. The moduli of
nine genuine lepton mixing matrix elements can then be calculated in terms of
the matter-corrected ones, and the latter can directly be determined from a
variety of long-baseline neutrino oscillations. We show that it is possible to
reconstruct the leptonic unitarity triangles and CP violation in a similar
parametrization-independent way.Comment: 12 pages, 1 figur
Higher absorbed solar radiation partly offset the negative effects of water stress on the photosynthesis of Amazon forests during the 2015 drought
Amazon forests play an important role in the global carbon cycle and Earth\u27s climate. The vulnerability of Amazon forests to drought remains highly controversial. Here we examine the impacts of the 2015 drought on the photosynthesis of Amazon forests to understand how solar radiation and precipitation jointly control forest photosynthesis during the severe drought. We use a variety of gridded vegetation and climate datasets, including solar-induced chlorophyll fluorescence (SIF), photosynthetic active radiation (PAR), the fraction of absorbed PAR (APAR), leaf area index (LAI), precipitation, soil moisture, cloud cover, and vapor pressure deficit (VPD) in our analysis. Satellite-derived SIF observations provide a direct diagnosis of plant photosynthesis from space. The decomposition of SIF to SIF yield (SIFyield) and APAR (the product of PAR and fPAR) reveals the relative effects of precipitation and solar radiation on photosynthesis. We found that the drought significantly reduced SIFyield, the emitted SIF per photon absorbed. The higher APAR resulting from lower cloud cover and higher LAI partly offset the negative effects of water stress on the photosynthesis of Amazon forests, leading to a smaller reduction in SIF than in SIFyield and precipitation. We further found that SIFyield anomalies were more sensitive to precipitation and VPD anomalies in the southern regions of the Amazon than in the central and northern regions. Our findings shed light on the relative and combined effects of precipitation and solar radiation on photosynthesis, and can improve our understanding of the responses of Amazon forests to drought
Group and Tri-bimaximal Neutrino Mixing -- A Renormalizable Model
The tetrahedron group has been widely used in studying neutrino mixing
matrix. It provides a natural framework of model building for the tri-bimaximal
mixing matrix. In this class of models, it is necessary to have two Higgs
fields, and , transforming under as 3 with one of them
having vacuum expectation values for the three components to be equal and
another having only one of the components to be non-zero. These specific vev
structures require separating and from communicating with each
other. The clash of the different vev structures for and is the
so called sequestering problem. In this work, I show that it is possible to
construct renormalizable supersymmetric models producing the tri-bimaximal
neutrino mixing with no sequestering problem.Comment: 4 page
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