2,674 research outputs found
Forecasting and Hedging Crop Input Prices
Replaced with edited version of paper 12/23/08.Farm Management,
Explicit SO(10) Supersymmetric Grand Unified Model for the Higgs and Yukawa Sectors
A complete set of fermion and Higgs superfields is introduced with
well-defined SO(10) properties and U(1) x Z_2 x Z_2 family charges from which
the Higgs and Yukawa superpotentials are constructed. The structures derived
for the four Dirac fermion and right-handed Majorana neutrino mass matrices
coincide with those previously obtained from an effective operator approach.
Ten mass matrix input parameters accurately yield the twenty masses and mixings
of the quarks and leptons with the bimaximal atmospheric and solar neutrino
vacuum solutions favored in this simplest version.Comment: Published version appearing in PRL in which small modifications to
original submission and a paragraph concerning proton decay appea
Realization of the Large Mixing Angle Solar Neutrino Solution in an SO(10) Supersymmetric Grand Unified Model
An SO(10) supersymmetric grand unified model proposed earlier leading to the
solar solution involving ``just-so'' vacuum oscillations is reexamined to study
its ability to obtain the other possible solar solutions. It is found that all
four viable solar neutrino oscillation solutions can be achieved in the model
simply by modification of the right-handed Majorana neutrino mass matrix, M_R.
Whereas the small mixing and vacuum solutions are easily obtained with several
texture zeros in M_R, the currently-favored large mixing angle solution
requires a nearly geometric hierarchical form for M_R that leads by the seesaw
formula to a light neutrino mass matrix which has two or three texture zeros.
The form of the matrix which provides the ``fine-tuning'' necessary to achieve
the large mixing angle solution can be understood in terms of Froggatt-Nielsen
diagrams for the Dirac and right-handed Majorana neutrino mass matrices. The
solution fulfils several leptogenesis requirements which in turn can be
responsible for the baryon asymmetry in the universe.Comment: 14 pages including 2 figure
Bound-State Model of Weak and Strong Interactions
The pion-nucleon coupling constant is calculated from first principles by use of the N/D matrix method. Three models are introduced which contain pions, nucleons, and weakly interacting intermediate bosons of the scalar, pseudoscalar, and vector variety. The basic interactions are taken to be parity and isotopic spin conserving. Certain physical assumptions in the nature of boundary conditions and the known fact that the weak coupling is very weak, together with use of the Born approximation for N, enable us to obtain an eigenvalue equation which expresses the pion-nucleon coupling constant in terms of the three masses in the problem. The correct value for gπ^2 can be obtained for an intermediate vector meson of mass comparable to the nucleon mass with essentially no cutoff employed; on the other hand, the experimental value is also obtained with a spin-zero boson and a relatively small cutoff energy
Resonant leptogenesis in a predictive SO(10) grand unified model
An SO(10) grand unified model considered previously by the authors featuring
lopsided down quark and charged lepton mass matrices is successfully predictive
and requires that the lightest two right-handed Majorana neutrinons be nearly
degenerate in order to obtain the LMA solar neutrino solution. Here we use this
model to test its predictions for baryogenesis through resonant-enhanced
leptogenesis. With the conventional type I seesaw mechanism, the best
predictions for baryogenesis appear to fall a factor of three short of the
observed value. However, with a proposed type III seesaw mechanism leading to
three pairs of massive pseudo-Dirac neutrinos, resonant leptogenesis is
decoupled from the neutrino mass and mixing issues with successful baryogenesis
easily obtained.Comment: 22 pages including 1 figure; published version with reference adde
RISK ANALYSIS OF ADOPTING ZERO RUNOFF SUBIRRIGATION SYSTEMS IN GREENHOUSE OPERATIONS: A MONTE CARLO SIMULATION APPROACH
Zero runoff subirrigation (ZRS) technology can effectively manage fertilizer input while improving greenhouse production efficiency. However, high capital investment costs and inadequate technical information to growers are impediments for adoption. A Monte Carlo simulation was used to compare the profitability and risks of alternative ZRS system investments for greenhouse operations in the northeastern and north central United States. Results showed that the Dutch movable tray system and the flood floor system were most profitable and least risky for small potted plant and bedding crop flat production, respectively. The trough bench system was least favorable because its profitability was low and highly volatile.Risk and Uncertainty,
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