3,876 research outputs found
A complete survey of texture zeros in general and symmetric quark mass matrices
We perform a systematic analysis of all possible texture zeros in general and
symmetric quark mass matrices. Using the values of masses and mixing parameters
at the electroweak scale, we identify for both cases the maximally restrictive
viable textures. Furthermore, we investigate the predictive power of these
textures by applying a numerical predictivity measure recently defined by us.
With this measure we find no predictive textures among the viable general quark
mass matrices, while in the case of symmetric quark mass matrices most of the
15 maximally restrictive textures are predictive with respect to one or more
light quark masses.Comment: 11 pages, no figure
A complete survey of texture zeros in the lepton mass matrices
We perform a systematic and complete analysis of texture zeros in the lepton
mass matrices and identify all viable and maximally restrictive cases of pairs
(M_\ell, M_D) and (M_\ell, M_L), where M_\ell, M_D and M_L are the
charged-lepton, Dirac neutrino and Majorana neutrino mass matrices,
respectively. To this end, we perform a thorough analysis of textures which are
equivalent through weak-basis permutations. Furthermore, we introduce numerical
measures for the predictivity of textures and apply them to the viable and
maximally restrictive texture zero models. It turns out that for Dirac
neutrinos these models can at most predict the smallest neutrino mass and the
CKM-type phase of the mixing matrix. For Majorana neutrinos most models can, in
addition, predict the effective neutrino mass for neutrinoless double beta
decay. Apart from one model, which has marginal predictive power with respect
to sin^2(theta_23), no other model can predict any of the already measured
observables.Comment: 32 pages, 1 figure; corrections in the computer code, numerical
analysis repeated, conclusions almost unchanged, changes in tables 9-1
Structure of giant nuclear molecules
Strong indirect evidence exists for the existence of attractive forces between nuclei making surface contact. Experimentally, the recent observations of spontaneous positron production in heavy-ion collisions can only be understood if nuclei stick together for times long compared to the collision time. We show that any such tendency for nuclei to attract implies the existence of nuclear molecules with entirely new kinds of collective modes. We present a simple model for these modes and apply it to 238U-238U
Different deformations of proton and neutron distributions in nuclei
Different collective deformation coordinates for neutrons and protons are introduced to allow for both stretching and γ transitions consistent with experiments. The rotational actinide nuclei 234-238U and 232Th are successfully analyzed in this model. NUCLEAR STRUCTURE 232Th, 234-238U calculated B (E2) values, collective model
The effect of silicia concentration on the time of set of constant pH
When an aqueous solution of sodium silicate is treated with an acid, the mixture will become increasingly viscous and opalescent, and will finally set, it the silica concentration exceeds 2% and if the gel is not too acid or too alkaline. The time of set is determined by the pH, concentration of silica, concentration of certain foreign substances and the temperature
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