Possible Z-width probe of a "brane-world" scenario for neutrino masses

The possibility that the accurately known value of the Z width might furnish information about the coupling of two neutrinos to the Majoron (Nambu-Goldstone boson of spontaneous lepton number violation) is proposed and investigated in detail. Both the "ordinary" case and the case in which one adopts a "brane" world picture with the Majoron free to travel in extra dimensions are studied. Bounds on the dimensionless coupling constants are obtained, allowing for any number of extra dimensions and any intrinsic mass scale. These bounds may be applied to a variety of different Majoron models. If a technically natural see-saw model is adopted, the predicted coupling constants are far below these upper bounds. In addition, for this natural model, the effect of extra dimensions is to decrease the predicted partial Z width, the increase due to many Kaluza-Klein excitations being compensated by the decrease of their common coupling constant.Comment: RevTeX, 12 pages, 3 figure

Additional phases induced by the supersymmetric CP phases

The explicit CP violation in the MSSM radiatively induces a finite unremovable alignment between the Higgs doublets. This additinal phase can be as large as the original CP phases in certain portions of the MSSM parameter space. Considering the specific case of the charginos, this additional phase is shown to induce a conceivable amount of CP violation near the would--be CP conserving points. Moreover, the CP violation in the absence of this phase is smaller than the one in the presence of it, and the former can never compete with the latter, however large $\tan\beta$ is.Comment: 29 pp, 15 fig

Vacuum Stability Higgs Mass Bound Revisited with Implications for Extra Dimension Theories

We take the standard model to be an effective theory including higher dimensional operators suppressed by scale $\Lambda$ and re-examine the higgs mass bounds from the requirements of vacuum stability. Our results show that the effects of the higher dimensional operators on the higgs mass limits are significant. As an implication of our results, we study the vacuum stability higgs mass bounds in theories with extra dimensions.Comment: Latex, 14 pages, 1 figure. Added references. To appear in Phys. Rev.

Views of young, rural African Americans of the role of community social institutions in HIV prevention.

BACKGROUND: We explored rural African American youths' perceptions about the role of community social institutions in addressing HIV. METHODS: We conducted four focus groups with African Americans aged 16 to 24 years in two rural counties in North Carolina. Groups were stratified by gender and risk status. We used a grounded theory approach to content analysis. RESULTS: Participants identified four social institutions as primary providers of HIV-related health promotion efforts: faith organizations, schools, politicians, and health agencies. They reported perceiving a lack of involvement in HIV prevention by faith-based organizations, constraints of abstinence-based sex education policies, politicians' lack of interest in addressing broader HIV determinants, and inadequacies in health agency services, and viewed all of these as being counter-productive to HIV prevention efforts. CONCLUSIONS: Youth have important insights about local social institutions that should be considered when designing HIV prevention interventions that partner with local organizations

A supernova constraint on bulk majorons

In models with large extra dimensions all gauge singlet fields can in principle propagate in the extra dimensional space. We have investigated possible constraints on majoron models of neutrino masses in which the majorons propagate in extra dimensions. It is found that astrophysical constraints from supernovae are many orders of magnitude stronger than previous accelerator bounds. Our findings suggest that unnatural types of the "see-saw" mechanism for neutrino masses are unlikely to occur in nature, even in the presence of extra dimensions.Comment: Minor changes, matches the version to appear in PR

Decoherence of entangled kaons and its connection to entanglement measures

We study the time evolution of the entangled kaon system by considering the Liouville - von Neumann equation with an additional term which allows for decoherence. We choose as generators of decoherence the projectors to the 2-particle eigenstates of the Hamiltonian. Then we compare this model with the data of the CPLEAR experiment and find in this way an upper bound on the strength $\lambda$ of the decoherence. We also relate $\lambda$ to an effective decoherence parameter $\zeta$ considered previously in literature. Finally we discuss our model in the light of different measures of entanglement, i.e. the von Neumann entropy $S$, the entanglement of formation $E$ and the concurrence $C$, and we relate the decoherence parameter $\zeta$ to the loss of entanglement: $1 - E$.Comment: comments and references added, 18 pages, 1 figur

The construction of marketing measures: the case of viewability

This study seeks to develop a critical understanding of marketing measures. Marketing measures inform a variety of marketing practices and have been subject to ethical, discursive and epistemological critique. Informed by a range of theoretical work, this study sheds light on the construction of a key marketing measure in digital advertising: viewability. It shows how a range of competing interests can be mobilized and aligned; how an object of interest can be stabilized; and how standards for measurement can be reconciled. Across this account, we can see how issues of accuracy, ideology and ethics are bracketed off as participants agree on which things matter and which things count

The Three Families from SU(4)A⊗SU(3)C⊗SU(2)L⊗U(1)XSU(4)_A\otimes SU(3)_C\otimes SU(2)_L\otimes U(1)_X SM-like Chiral Models

We give a detailed description of the model construction procedures about our new approach to the family structure of the standard model. SM-like chiral fermion spectra, largely "derivable" from the gauge anomaly constraints, are formulated in a $SU(N)\otimes SU(3)\otimes SU(2)\otimes U(1)$ symmetry framework as an extension of the SM symmetry. The $N=4$ case gives naturally three families as a result, with $U(1)_Y$ nontrivially embedded into the $SU(4)_A\otimes U(1)_X$. Such a spectrum has extra vector-like quarks and leptons. We illustrate how an acceptable symmetry breaking pattern can be obtained through a relatively simple scalar sector which gives naturally hierarchical quark mass matrices. Compatibility with various FCNC constraints and some interesting aspects of the possible phenomenological features are discussed, from a non-model specific perspective. The question of incorporating supersymmetry without putting in the Higgses as extra supermultiplet is also addressed.Comment: 43 pages RevTex, including 9 tables and 3 figure