Effective weak Hamiltonian for the Δb =1nonleptonic decays in the six-quark model

ABSTRACT: Quantum-chromodynamic corrections and flavor-symmetry-breaking effects are considered in the leadinglogarithmic approximation for the calculation of the db = 1 nonleptonic effective weak Hamiltonian in the context of the Kobayashi-Maskawa model. It is found that flavor-symmetry breaking is very important for the cases under consideration here

An [SU(3)]4 supersymmetric grand unified model

ABSTRACT: We present a grand unified model based on the supersymmetric SU(3)L⊗SU(3)CL⊗SU(3)CR⊗SU(3)R gauge group, which unifies in one single step the three gauge couplings of the standard model at an scale M∼1018 GeV, and spontaneously breaks down to SU(3)c⊗U(1)EM using only fundamental representations of SU(3). In this model the proton decay is highly suppressed and the doublet-triplet problem is lessened. The see-saw mechanism for the neutrinos is readily implemented with the use of an extra tiny mass sterile neutral particle for each generation which provides a natural explanation to the neutrino puzzle

SU(3)c⊗SU(4)L⊗U(1)X without exotic electric charges

ABSTRACT: We present an extension of the standard model to the local gauge group SU(3)c⊗SU(3)L⊗U(1)X with a family nonuniversal treatment and anomalies canceled among the three families in a nontrivial fashion. The mass scales, the gauge boson masses, and the masses for the spin 1/2 particles in the model are analyzed. The neutral currents coupled to all neutral vector bosons in the model are studied, and particular values of the parameters are used in order to simplify the mixing between the three neutral currents present in the theory, mixing which is further constrained by experimental results from the CERN LEP, SLAC Linear Collider, and atomic parity violation

Mass scales and stability of the proton in [SU(6)]3 X Z3

ABSTRACT: We prove that the proton is stable in the gauge model [SU(6)] x Zs which uni6es nongravitational forces with Savors, broken spontaneously by a minimal set of Higgs fields and vacuum expectation values down to SU(3)cU(1)aM. We also compute the evolution of the gauge coupling constants and show how agreement with precision data can be obtained

SU(3)c⊗SU(4)L⊗U(1)X model for three families

ABSTRACT: An extension of the Standard Model to the local gauge group SU(3)c⊗SU(4)L⊗U(1)XSU(3)c⊗SU(4)L⊗U(1)X as a three-family model is presented. The model does not contain exotic electric charges and we obtain a consistent mass spectrum by introducing an anomaly-free discrete Z2Z2 symmetry. The neutral currents coupled to all neutral vector bosons in the model are studied. By using experimental results from the CERN LEP, SLAC Linear Collider and atomic parity violation we constrain the mixing angle between two of the neutral currents in the model and the mass of the additional neutral gauge bosons to be −0.0032≤sinθ≤0.0031−0.0032≤sin⁡θ≤0.0031 and 0.67TeV≤MZ2≤6.10.67TeV≤MZ2≤6.1 TeV at 95% C.L., respectively

Hierarchical radiative masses in a supersymmetric three-family model without Higgsinos

ABSTRACT: We study the scalar potential and the mass spectrum of the supersymmetric extension of a three-family model based on the local gauge group SU(3)C⊗SU(3)L⊗U(1)X, with anomalies canceled among the three families in a nontrivial fashion. In this model the slepton multiplets play the role of the Higgs scalars and no Higgsinos are needed, with the consequence that the sneutrino, the selectron and six other sleptons play the role of the Goldstone bosons of the theory. By introducing an Abelian anomaly-free discrete symmetry and aligning the vacuum in a convenient way, we get a consistent mass spectrum for the scalars and for the spin 1/2 quarks and charged leptons, where only the top and charm quarks and the tau lepton acquire tree level masses while the remaining ordinary charged fermions acquire radiative hierarchical masses

Five texture zeros and CP violation for the standard model quark mass matrices

ABSTRACT: The phenomenology of the five independent sets of 3 3 quark mass matrices with five texture zeros is carried through in full detail, including predictions for the CP-violation asymmetries. Our study is done without any approximation, first analytically and then numerically

Lepton number violation and neutrino masses in 3-3-1 models

ABSTRACT: Lepton number violation and its relation to neutrino masses are investigated in several versions of the (3) ⊗ (3) ⊗ (1) model. Spontaneous and explicit violation and conservation of the lepton number are considered. In one of the models (the socalled economical one), the lepton number is spontaneously violated and it is found that the would be Majoron is not present because it is gauged away, providing in this way the longitudinal polarization component to a now massive gauge field

Teoría económica aplicada

El objetivo de este libro es lograr un mayor acercamiento entre los trabajos meramente cuantitativos y los puramente teóricos. Así, los quince trabajos presentados desarrollan modelos teóricos para representar la situación a estudiar de la realidad mexicana y son complementados con información cuantitativa. Se incluyen diversos temas que van desde el análisis de la conducta de los delincuentes y el entorno en que actúan, hasta el análisis de legislaciones que rigen diversas actividades y mercados. Se habla de seguridad social, impuestos, banca de desarrollo, sector externo, servicios públicos como agua, educación, trabajo infantil, costo compartido, discriminación de precios, reglas de reparto y seguros de vida. La intención es invitar al lector a conocer la relevancia de la teoría económica y sus modelos cuantitativos en las decisiones de la vida real.Enrique R. Casares; Leobardo Plata, compiladore

Carbon-sensitive pedotransfer functions for plant available water

Currently accepted pedotransfer functions show negligible effect of management-induced changes to soil organic carbon (SOC) on plant available water holding capacity (θAWHC), while some studies show the ability to substantially increase θAWHC through management. The Soil Health Institute\u27s North America Project to Evaluate Soil Health Measurements measured water content at field capacity using intact soil cores across 124 long-term research sites that contained increases in SOC as a result of management treatments such as reduced tillage and cover cropping. Pedotransfer functions were created for volumetric water content at field capacity (θFC) and permanent wilting point (θPWP). New pedotransfer functions had predictions of θAWHC that were similarly accurate compared with Saxton and Rawls when tested on samples from the National Soil Characterization database. Further, the new pedotransfer functions showed substantial effects of soil calcareousness and SOC on θAWHC. For an increase in SOC of 10 g kg–1 (1%) in noncalcareous soils, an average increase in θAWHC of 3.0 mm 100 mm–1 soil (0.03 m3 m–3) on average across all soil texture classes was found. This SOC related increase in θAWHC is about double previous estimates. Calcareous soils had an increase in θAWHC of 1.2 mm 100 mm–1 soil associated with a 10 g kg–1 increase in SOC, across all soil texture classes. New equations can aid in quantifying benefits of soil management practices that increase SOC and can be used to model the effect of changes in management on drought resilience