Maximal Neutrino Mixing from a Minimal Flavor Symmetry

We study a number of models, based on a non-Abelian discrete group, that successfully reproduce the simple and predictive Yukawa textures usually associated with U(2) theories of flavor. These models allow for solutions to the solar and atmospheric neutrino problems that do not require altering successful predictions for the charged fermions or introducing sterile neutrinos. Although Yukawa matrices are hierarchical in the models we consider, the mixing between second- and third-generation neutrinos is naturally large. We first present a quantitative analysis of a minimal model proposed in earlier work, consisting of a global fit to fermion masses and mixing angles, including the most important renormalization group effects. We then propose two new variant models: The first reproduces all important features of the SU(5)xU(2) unified theory with neither SU(5) nor U(2). The second demonstrates that discrete subgroups of SU(2) can be used in constructing viable supersymmetric theories of flavor without scalar universality even though SU(2) by itself cannot.Comment: 34 pages LaTeX, 1 eps figure, minor revisions and references adde

Neutrino masses: From fantasy to facts

Theory suggests the existence of neutrino masses, but little more. Facts are coming close to reveal our fantasy: solar and atmospheric neutrino data strongly indicate the need for neutrino conversions, while LSND provides an intriguing hint. The simplest ways to reconcile these data in terms of neutrino oscillations invoke a light sterile neutrino in addition to the three active ones. Out of the four neutrinos, two are maximally-mixed and lie at the LSND scale, while the others are at the solar mass scale. These schemes can be distinguished at neutral-current-sensitive solar & atmospheric neutrino experiments. I discuss the simplest theoretical scenarios, where the lightness of the sterile neutrino, the nearly maximal atmospheric neutrino mixing, and the generation of $\Delta {m^2}_\odot$ & $\Delta {m^2}_{atm}$ all follow naturally from the assumed lepton-number symmetry and its breaking. Although the most likely interpretation of the present data is in terms of neutrino-mass-induced oscillations, one still has room for alternative explanations, such as flavour changing neutrino interactions, with no need for neutrino mass or mixing. Such flavour violating transitions arise in theories with strictly massless neutrinos, and may lead to other sizeable flavour non-conservation effects, such as $\mu \to e + \gamma$, $\mu-e$ conversion in nuclei, unaccompanied by neutrino-less double beta decay.Comment: 33 pages, latex, 16 figures. Invited Talk at Ioannina Conference, Symmetries in Intermediate High Energy Physics and its Applications, Oct. 1998, to be published by Springer Tracts in Modern Physics. Festschrift in Honour of John Vergados' 60th Birthda

Decision support systems for target setting & resource allocation in multi-unit & multi-level organisations using data envelopment analysis

SIGLEAvailable from British Library Document Supply Centre- DSC:DX187292 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Technical efficiency and economies of scale in state owned enterprises: The Hellenic telecommunications organisation

In this paper we propose methodologies for assessing the relative efficiency of state owned enterprises that operate under monopolistic conditions. Irrespective of the ownership structure (private or public) monopolistic operation is often given unclear/conflicting operating objectives by their principals or regulators and thus efficiency should be assessed using alternative objectives such as cost, production and revenue. On the methodological side the paper employs parametric functional forms using ordinary least squares and goal programming methods of estimation. A secondary estimation stage was also pursued with the input/output variables of the models being corrected for technical inefficiency. The methodology was applied to examine the technical efficiency and economies of scale of the Hellenic telecommunications organisation over the period 1971-1993. © 1998 Elsevier Science B.V

Modeling customer satisfaction in telecommunications: Assessing the effects of multiple transaction points on the perceived overall performance of the provider

The ability of telecommunication operators to focus successfully on the customer has proven to be one of the most competitive issues toward the end of the 20th century. The services management literature is short of theoretical and empirical studies on customer satisfaction measurement in the telecommunications industry. This, however, is contrary to the industry practice since almost all major telecommunications companies around the world gather information about customer satisfaction and other related information about the quality of their services. Our research focuses on the customer satisfaction function of residential customers of a major European telecommunications company. Customer satisfaction is seen as the overall performance of the telecommunications company stemming from adequate service provision, value for money, loyalty, and relationship management. The antecedents of the performance of the organization are obtained from the contact points between the customers and the service points of the telecommunications company

The evolution of non-paprametric frontier analysis methods A review & recent developments

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A network representation of decentralised target-based resource management of public services

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Goal programming & data envelopment analysis (GoDEA) for target-based multi-level planning

Available from British Library Document Supply Centre- DSC:9261.954(WBS-RP--144) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Multivariate & frontier analysis for assessing the market & cost efficiency of large scale bank branch networks

SIGLEAvailable from British Library Document Supply Centre- DSC:9261.954(WBS-RB-RP--168) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Production functions and technical change in multimarket oligopoly Theory and evidence

SIGLEAvailable from British Library Document Supply Centre- DSC:9261.954(WBS-RB-RP--162) / BLDSC - British Library Document Supply CentreGBUnited Kingdo