17,596 research outputs found
Neutrino Masses and Absence of Flavor Changing Interactions in the 2HDM from Gauge Principles
We propose several Two Higgs Doublet Models with the addition of an Abelian
gauge group which free the usual framework from flavor changing neutral
interactions and explain neutrino masses through the seesaw mechanism. We
discuss the kinetic and mass-mixing gripping phenomenology which encompass
several constraints coming from atomic parity violation, the muon anomalous
magnetic moment, rare meson decays, Higgs physics, LEP precision data,
neutrino-electron scattering, low energy accelerators and LHC probes.Comment: 54 pages, 10 figure
The Portuguese-speaking community in Lambeth: a scoping study
This report presents the findings from research with the Portuguese-speaking community in Lambeth commissioned by the London Community Foundation. It is designed to inform the work of the Lambeth Community Fund Grant Committee which makes decisions regarding the distribution the Portuguese Speakers Community Fund. Based mainly on semi-structured, face to face interviews with community representatives and local service providers, it provides a snapshot of the Portuguese-speaking community in Lambeth, its make-up, needs and support structure
Lepton Flavor Violation and Collider Searches in a Type I + II Seesaw Model
Neutrino are massless in the Standard Model. The most popular mechanism to
generate neutrino masses are the type I and type II seesaw, where right-handed
neutrinos and a scalar triplet are augmented to the Standard Model,
respectively. In this work, we discuss a model where a type I + II seesaw
mechanism naturally arises via spontaneous symmetry breaking of an enlarged
gauge group. Lepton flavor violation is a common feature in such setup and for
this reason, we compute the model contribution to the
and decays. Moreover, we explore the connection between
the neutrino mass ordering and lepton flavor violation in perspective with the
LHC, HL-LHC and HE-LHC sensitivities to the doubly charged scalar stemming from
the Higgs triplet. Our results explicitly show the importance of searching for
signs of lepton flavor violation in collider and muon decays. The conclusion
about which probe yields stronger bounds depends strongly on the mass ordering
adopted, the absolute neutrino masses and which much decay one considers. In
the 1-5 TeV mass region of the doubly charged scalar, lepton flavor violation
experiments and colliders offer orthogonal and complementary probes. Thus if a
signal is observed in one of the two new physics searches, the other will be
able to assess whether it stems from a seesaw framework.Comment: 41 pages, 1 figure, 2 table
Chemical abundances for the transiting planet host stars OGLE-TR-10, 56, 111, 113, 132 and TrES-1. Abundances in different galactic populations
We used the UVES spectrograph (VLT-UT2 telescope) to obtain high-resolution
spectra of 6 stars hosting transiting planets, namely for OGLE-TR-10, 56, 111,
113, 132 and TrES-1. The spectra are now used to derive and discuss the
chemical abundances for C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni,
Cu and Zn. Abundances were derived in LTE, using 1-D plane-parallel Kurucz
model atmospheres. For S, Zn and Cu we used a spectral synthesis procedure,
while for the remaining cases the abundances were derived from measurements of
line-equivalent widths. The resulting abundances are compared with those found
for stars in the solar neighborhood. Distances and galactic coordinates are
estimated for the stars. We conclude that besides being particularly
metal-rich, with small possible exceptions OGLE-TR-10, 56, 111, 113, 132 and
TrES-1 are chemically undistinguishable from the field (thin disk) stars
regarding their [X/Fe] abundances. This is particularly relevant for the most
distant of the targets, located at up to ~2 Kpc from the Sun. We also did not
find any correlation between the abundances and the condensation temperature of
the elements, an evidence that strong accretion of planetary-like material,
tentatively connected to planetary migration, did not occur.Comment: Accepted for publication in Astronomy & Astrophysics (June 2006
Metodologia para determinação de ácido ascórbico em sucos de citrus utilizando cromatografia líquida de alta eficiência.
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Portuguese Adaptation of Students Engagement in Schools International Scale (SESIS)
The importance of student’s engagement has been recently pointed out in research. However, there has been a lack of engagement assessment instrument, pertaining psychometric qualities. Objective: This paper presents the Portuguese adaptation of the “Student’s Engagement in School International Scale” (SESIS), drawn up from a12 countries international study (Lam et al., 2012; Lam et al., in press). Method: Psychometric properties of this scale were examined with data from 685 students from different grades (6th, 7th, 9th and 10th), from both sexes, and different regions of the country. Results: Factorial analysis of the results, with varimax rotation, lead to three different factors which explain 50.88% of the variance. The scale integrates the original 33 items, and cognitive, affective and behavioural dimensions. For the external validity study, the relationship between student’s engagement in school results and other school variables — academic performance, self-concept — was considered, and significant relations were observed, as expected. Conclusion: The data presented highlights the qualities of SESIS, as well as its usefulness for research purposes. Suggestion: It is suggested the investigation of the extension of SESIS’s three-dimensionality, in future studiesKeywords: Innovation, technology, research projects, etc. [Arial 10-point, justified alignment]
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