3,211 research outputs found
PSL(2,7) Representations and their relevance to Neutrino Physics
The investigation of the role of finite groups in flavor physics and
particularly, in the interpretation of the neutrino data has been the subject
of intensive research. Motivated by this fact, in this work we derive the
three-dimensional unitary representations of the projective linear group
PSL_2(7). Based on the observation that the generators of the group exhibit a
latin square pattern, we use available computational packages on discrete
algebra to determine the generic properties of the group elements. We present
analytical expressions and discuss several examples which reproduce the
neutrino mixing angles in accordance with the experimental data.Comment: 21 pages, 3 figure
Towards a realistic Standard Model from D-brane configurations
Effective low energy models arising in the context of D-brane configurations
with Standard Model (SM) gauge symmetry extended by several gauged abelian
factors are discussed. The models are classified according to their hypercharge
embeddings consistent with the SM spectrum hypercharge assignment. Particular
cases are analyzed according to their perspectives and viability as low energy
effective field theory candidates. The resulting string scale is determined by
means of a two-loop renormalization group calculation. Their implications in
Yukawa couplings, neutrinos and flavor changing processes are also presented.Comment: 22 pages, 12 EPS figures, some clarifications/references adde
Inverted neutrino mass hierarchies from U(1) symmetries
Motivated by effective low energy models of string origin, we discuss the
neutrino masses and mixing within the context of the Minimal Supersymmetric
Standard Model supplemented by a U(1) anomalous family symmetry and additional
Higgs singlet fields charged under this extra U(1). In particular, we interpret
the solar and atmospheric neutrino data assuming that there are only three
left-handed neutrinos which acquire Majorana masses via a lepton number
violating dimension-five operator. We derive the general form of the charged
lepton and neutrino mass matrices when two different pairs of singlet Higgs
fields develop non--zero vacuum expectation values and show how the resulting
neutrino textures are related to approximate lepton flavor symmetries. We
perform a numerical analysis for one particular case and obtain solutions for
masses and mixing angles, consistent with experimental data.Comment: 15 pages, 4 figure
Modeling the Scientific Dimension of Academic Conferences
AbstractThe rapid spread of the Internet and the growing trend towards research are the leading factors and strong springboards, for the Industry of conference organizations, to proceed with further development. With the increase of shareholding in organizing events, the environment has become very complex. The Conference Organizing Committee is challenged to define a wide range of factors, in order to better serve the needs and objectives of the Conference.The main topic of this research is the study and modeling of the scientific dimension of Academic Conferences. We studied and recorded the basic procedures that govern the organization of scientific conferences. These are the procedures that affect the way that scientific conferences are conducted and eventually of course, the success or failure of those. Our research is engaged in the scientific aspect of these conferences, as the majority of the participants are scientifically renowned academics
Developmental Risk: Evidence from Large Nonrighthanded Samples
The aim of the present study is twofold. First, we tested the view that individuals who do not develop a typically strong behavioral
laterality are distributed differentially among the two genders across age. Second, we examined whether left handedness and mixed
handedness are associated with an elevated risk of some developmental or cognitive deficits. A special recruitment procedure
provided norms of the Rey-Osterrieth Complex Figure (ROCF) copy from large samples of left-handed ( = 420) and mixedhanded
( = 72) compared to right-handed ( = 420) schoolchildren and adults ( = 545). This graphic task was considered as
reflective of the growth of visual-spatial skills and impairment at copying as a developmental risk. Subjects' hand preference was
assessed by the Edinburgh Handedness Inventory. Data analysis indicated that (1) the trend towards consistent right handedness
is sex related. Girls are clearly ahead of boys in this lateralization process, and boys are overrepresented in mixed-handed subjects.
The greater prevalence of mixed-handed boys compared to girls decreases with age. (2) Performance on drawing the ROCF varies
according to age and handedness groups.Mixed-handed subjects scoredworse in all age groups.The results are discussed in relation
to the hormonal-developmental, neuropathological, and learning theories of lateralization
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