Flavor-phenomenology of two-Higgs-doublet models with generic Yukawa structure

In this article, we perform an extensive study of flavor observables in a two-Higgs-doublet model with generic Yukawa structure (of type III). This model is interesting not only because it is the decoupling limit of the minimal supersymmetric standard model but also because of its rich flavor phenomenology which also allows for sizable effects not only in flavor-changing neutral-current (FCNC) processes but also in tauonic B decays. We examine the possible effects in flavor physics and constrain the model both from tree-level processes and from loop observables. The free parameters of the model are the heavy Higgs mass, tanβ (the ratio of vacuum expectation values) and the “nonholomorphic” Yukawa couplings ϵfij(f=u,d,ℓ). In our analysis we constrain the elements ϵfij in various ways: In a first step we give order of magnitude constraints on ϵfij from ’t Hooft’s naturalness criterion, finding that all ϵfij must be rather small unless the third generation is involved. In a second step, we constrain the Yukawa structure of the type-III two-Higgs-doublet model from tree-level FCNC processes (Bs,d→μ+μ−, KL→μ+μ−, D¯¯¯0→μ+μ−, ΔF=2 processes, τ−→μ−μ+μ−, τ−→e−μ+μ− and μ−→e−e+e−) and observe that all flavor off-diagonal elements of these couplings, except ϵu32,31 and ϵu23,13, must be very small in order to satisfy the current experimental bounds. In a third step, we consider Higgs mediated loop contributions to FCNC processes [b→s(d)γ, Bs,d mixing, K−K¯¯¯ mixing and μ→eγ] finding that also ϵu13 and ϵu23 must be very small, while the bounds on ϵu31 and ϵu32 are especially weak. Furthermore, considering the constraints from electric dipole moments we obtain constrains on some parameters ϵu,ℓij. Taking into account the constraints from FCNC processes we study the size of possible effects in the tauonic B decays (B→τν, B→Dτν and B→D∗τν) as well as in D(s)→τν, D(s)→μν, K(π)→eν, K(π)→μν and τ→K(π)ν which are all sensitive to tree-level charged Higgs exchange. Interestingly, the unconstrained ϵu32,31 are just the elements which directly enter the branching ratios for B→τν, B→Dτν and B→D∗τν. We show that they can explain the deviations from the SM predictions in these processes without fine-tuning. Furthermore, B→τν, B→Dτν and B→D∗τν can even be explained simultaneously. Finally, we give upper limits on the branching ratios of the lepton flavor-violating neutral B meson decays (Bs,d→μe, Bs,d→τe and Bs,d→τμ) and correlate the radiative lepton decays (τ→μγ, τ→eγ and μ→eγ) to the corresponding neutral current lepton decays (τ−→μ−μ+μ−, τ−→e−μ+μ− and μ−→e−e+e−). A detailed Appendix contains all relevant information for the considered processes for general scalar-fermion-fermion couplings.

The phenomenology of lucid dreaming: An online survey.

In lucid dreams the dreamer is aware that he or she is dreaming. Although such dreams are not that uncommon, many aspects of lucid dream phenomenology are still unclear. An online survey was conducted to gather data about lucid dream origination, duration, active or passive participation in the dream, planned actions for lucid dreams, and other phenomenological aspects. Among the 684 respondents who filled out the questionnaire, there were 571 lucid dreamers (83.5%). According to their reports, lucid dreams most often originate spontaneously in adolescence. The average lucid dream duration is about 14 minutes. Lucid dreamers are likely to be active in their lucid dreams and plan to accomplish different actions (e.g., flying, talking with dream characters, or having sex), yet they are not always able to remember or successfully execute their intentions (most often because of awakening or hindrances in the dream environment). The frequency of lucid dream experience was the strongest predictor of lucid dream phenomenology, but some differences were also observed in relation to age, gender, or whether the person is a natural or self-trained lucid dreamer. The findings are discussed in light of lucid dream research, and suggestions for future studies are provided.

Online games for the teaching of mathematics

In this article we present a didactic experience developed by the GIE (Group of Educational Innovation) “Pensamiento Matemático” of the Polytechnics University of Madrid (UPM), in order to bring secondary students and university students closer to Mathematics. It deals with the development of a virtual board game called Mate-trivial. The mechanics of the game is to win points by going around the board which consists of four types of squares identified by colours: “Statistics and Probability”, “Calculus and Analysis”, “Algebra and Geometry” and “Arithmetic and Number Theory ”. When landing on a square, a question of its category is set out: a correct answer wins 200 points, if wrong it loses 100 points, and not answering causes no effect on the points, but all the same, two minutes out of the 20 minutes that each game lasts are lost. For the game to be over it is necessary, before those 20 minutes run out, to reach the central square and succeed in the final task: four chained questions, one of each type, which must be all answered correctly. It is possible to choose between two levels to play: Level 1, for pre-university students and Level 2 for university students. A prototype of the game is available at the website “Aula de Pensamiento Matemático” developed by the GIE: http://innovacioneducativa.upm.es/pensamientomatematico/. This activity lies within a set of didactic actions which the GIE is developing in the framework of the project “Collaborative Strategies between University and Secondary School Education for the teaching and learning of Mathematics: An Application to solve problems while playing”, a transversal project financed by the UPM.

A selective phenomenology of the seismicity of Southern California.

Predictions of earthquakes that are based on observations of precursory seismicity cannot depend on the average properties of the seismicity, such as the Gutenberg-Richter (G-R) distribution. Instead it must depend on the fluctuations in seismicity. We summarize the observational data of the fluctuations of seismicity in space, in time, and in a coupled space-time regime over the past 60 yr in Southern California, to provide a basis for determining whether these fluctuations are correlated with the times and locations of future strong earthquakes in an appropriate time- and space-scale. The simple extrapolation of the G-R distribution must lead to an overestimate of the risk due to large earthquakes. There may be two classes of earthquakes: the small earthquakes that satisfy the G-R law and the larger and large ones. Most observations of fluctuations of seismicity are of the rate of occurrence of smaller earthquakes. Large earthquakes are observed to be preceded by significant quiescence on the faults on which they occur and by an intensification of activity at distance. It is likely that the fluctuations are due to the nature of fractures on individual faults of the network of faults. There are significant inhomogeneities on these faults, which we assume will have an important influence on the nature of self-organization of seismicity. The principal source of the inhomogeneity on the large scale is the influence of geometry--i.e., of the nonplanarity of faults and the system of faults.

The curricular value of mathematics in non-mathematics degree

Higher education should provide the acquisition of skills and abilities that allow the student to play a full and active role in society. The educational experience should offer a series of conceptual, procedural and attitudinal contents that encourage “learning to know, learning to do, learning to be and learning to live together”. It is important to consider the curricular value of mathematics in the education of university undergraduates who do not intend to study mathematics but for whom the discipline will serve as an instrumental. This work discusses factors that form part of the debate on the curricular value of mathematics in non-mathematics degrees.

Do first-year university students understand the language of mathematics?

The aim of the project is to determine if the understanding of the language of Mathematics of students starting university is propitious to the development of an appropriate cognitive structure. The objective of this current work was to analyse the ability of first-year university students to translate the registers of verbal or written expressions and their representations to the registers of algebraic language. Results indicate that students do not understand the basic elements of the language of Mathematics and this causes them to make numerous errors of construction and interpretation. The students were not able to associate concepts with definitions and were unable to offer examples.

Perspectives of Teachers Regarding the Integration of Mathematics and Science at the Secondary School Level

The integration of mathematics and science in secondary schools in the 21st century continues to be an important topic of practice and research. The purpose of my research study, which builds on studies by Frykholm and Glasson (2005) and Berlin and White (2010), is to explore the potential constraints and benefits of integrating mathematics and science in Ontario secondary schools based on the perspectives of in-service and pre-service teachers with various math and/or science backgrounds. A qualitative and quantitative research design with an exploratory approach was used. The qualitative data was collected from a sample of 12 in-service teachers with various math and/or science backgrounds recruited from two school boards in Eastern Ontario. The quantitative and some qualitative data was collected from a sample of 81 pre-service teachers from the Queen’s University Bachelor of Education (B.Ed) program. Semi-structured interviews were conducted with the in-service teachers while a survey and a focus group was conducted with the pre-service teachers. Once the data was collected, the qualitative data were abductively analyzed. For the quantitative data, descriptive and inferential statistics (one-way ANOVAs and Pearson Chi Square analyses) were calculated to examine perspectives of teachers regardless of teaching background and to compare groups of teachers based on teaching background. The findings of this study suggest that in-service and pre-service teachers have a positive attitude towards the integration of math and science and view it as valuable to student learning and success. The pre-service teachers viewed the integration as easy and did not express concerns to this integration. On the other hand, the in-service teachers highlighted concerns and challenges such as resources, scheduling, and time constraints. My results illustrate when teachers perceive it is valuable to integrate math and science and which aspects of the classroom benefit best from the integration. Furthermore, the results highlight barriers and possible solutions to better the integration of math and science. In addition to the benefits and constraints of integration, my results illustrate why some teachers may opt out of integrating math and science and the different strategies teachers have incorporated to integrate math and science in their classroom.