Lifting a Realistic SO(10) Grand Unified Model to Five Dimensions

It has been shown recently that the problem of rapid proton decay induced by dimension five operators arising from the exchange of colored Higgsinos can be simply avoided in grand unified models where a fifth spatial dimension is compactified on an orbifold. Here we demonstrate that this idea can be used to solve the Higgsino-mediated proton decay problem in any realistic SO(10) model by lifting that model to five dimensions. A particular SO(10) model that has been proposed to explain the pattern of quark and lepton masses and mixings is used as an example. The idea is to break the SO(10) down to the Pati-Salam symmetry by the orbifold boundary conditions. The entire four-dimensional SO(10) model is placed on the physical SO(10) brane except for the gauge fields, the 45 and a single 10 of Higgs fields, which are placed in the five-dimensional bulk. The structure of the Higgs superpotential can be somewhat simplified in doing so, while the Yukawa superpotential and mass matrices derived from it remain essentially unaltered.Comment: 17 pages, version to be published in Phys. Rev. D with expanded discussion of the suppression of dim-5 proton decay operator

Radioisotopes Produced by Neutron Irradiation of Food

The use of neutrons for cargo interrogation has the potential to drastically improve threat detection. Previous research has focussed on the production of 24Na, based on the isotopes produced in pharmaceuticals and medical devices. For both the total acitivity and the ingestion dose we show that a variety of isotopes contribute and that 24Na is only dominant under certain conditions. The composition of the foods has a strong influence on the resulting activity and ingestion dose suggesting that the pharmaceuticals and medical devices considered initially are not a viable analogue for foodstuffs. There is an energy dependence to the isotopes produced due to the cross-sections of different reactions varying with neutron energy. We show that this results in different isotopes dominating the ingestion dose at different energies, which has not been considered in previous literature

Religious Orientation, Guilt, Confession, and Forgiveness

Religious orientation and psychological functioning were investigated in an analog study with 83 participants. After completing the Religious Orientation Scale (Allport & Ross, 1967), participants read a continuous narrative with three scenarios in which they first committed a dishonest act, and then felt compelled to confess what they had done. The final scenario contained a manipulation of grace or no-grace, in which half of the participants were forgiven for their act and half were not. Following each scenario, participants were tested for feelings of guilt and related behavioral and emotional responses. Intrinsically religious participants were more prone to guilt, more likely to confess their wrongdoing, and more likely to forgive themselves than extrinsically religious subjects. Guilt was found to have a mediating effect between intrinsic religiousness and some, but not all, outcome variables. The potentially beneficial consequences of guilt are discussed

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

Lepton Flavor Violation in Supersymmetric SO(10) Grand Unified Models

The study for lepton flavor violation combined with the neutrino oscillation may provide more information about the lepton flavor structure of the grand unified theory. In this paper, we study two lepton flavor violation processes, $\tau\to \mu\gamma$ and $Z\to \tau\mu$, in the context of supersymmetric SO(10) grand unified models. We find the two processes are both of phenomenological interest. In particular the latter may be important in some supersymmetric parameter space where the former is suppressed. Thus, Z-dacay may offer another chance for looking for lepton flavor violation.Comment: 26 pages, 10 figure

Radiological Risks of Neutron Interrogation of Food

In recent years there has been growing interest in the use of neutron scanning techniques for security. Neutron techniques with a range of energy spectra including thermal, white and fast neutrons have been shown to work in different scenarios. As international interest in neutron scanning increases the risk of activating cargo, especially foodstuffs must be considered. There has been a limited amount of research into the activation of foods by neutron beams and we have sought to improve the amount of information available. In this paper we show that for three important metrics; Activity, Ingestion Dose and Time to Background there is a strong dependence on the food being irradiated and a weak dependence on the energy of irradiation. Previous studies into activation used results based on irradiation of pharmaceuticals as the basis for research into activation of food. The earlier work reports that 24Na production is the dominant threat which motivated the search for 23(n;\gamma)24Na in highly salted foods. We show that 42K can be more significant than 24Na in low salt foods such as Bananas and Potatoes

Charged lepton contributions to the solar neutrino mixing and theta_13

A charged lepton contribution to the solar neutrino mixing induces a contribution to theta_13, barring cancellations/correlations, which is independent of the model building options in the neutrino sector. We illustrate two robust arguments for that contribution to be within the expected sensitivity of high intensity neutrino beam experiments. We find that the case in which the neutrino sector gives rise to a maximal solar angle (the natural situation if the hierarchy is inverse) leads to a theta_13 close to or exceeding the experimental bound depending on the precise values of theta_12, theta_23, an unknown phase and possible additional contributions. We finally discuss the possibility that the solar angle originates predominantly in the charged lepton sector. We find that the construction of a model of this sort is more complicated. We comment on a recent example of natural model of this type.Comment: 10 pages, 1 figur

Leptogenesis in the type III seesaw mechanism

It is shown that the type III seesaw mechanism proposed recently can have certain advantages over the conventional (or type I) seesaw mechanism for leptogenesis. In particular a resonant enhancement of leptogenesis via heavy quasi-Dirac right-handed neutrino pairs can occur without a special flavor form or "texture" of the mass matrices being assumed. Some of the requirements for neutrino mixing and leptogenesis are effectively decoupled.Comment: 12 pages including one figure, several references adde

The Stark effect in linear potentials

We examine the Stark effect (the second-order shift in the energy spectrum due to an external constant force) for two 1-dimensional model quantum mechanical systems described by linear potentials, the so-called quantum bouncer (defined by V(z) = Fz for z>0 and V(z) infinite for z<0) and the symmetric linear potential (given by V(z) = F|z|). We show how straightforward use of the most obvious properties of the Airy function solutions and simple Taylor expansions give closed form results for the Stark shifts in both systems. These exact results are then compared to other approximation techniques, such as perturbation theory and WKB methods. These expressions add to the small number of closed-form descriptions available for the Stark effect in model quantum mechanical systems.Comment: 15 pages. To appear in Eur. J. Phys. Needs Institute of Physics (iopart) style file

Antisymmetric Higgs representation in SO(10) for neutrinos

A Model based on SO(10) grand unified theory (GUT) and supersymmetry is presented to describe observed phenomena for neutrinos. The large mixing angles among different generations, together with the small masses, are attributed to the Higgs boson structure at the GUT energy scale. Quantitative discussions for these observables are given, taking into account their energy evolution.Comment: 10 page