2,750 research outputs found
Flavour Physics and CP Violation in the Standard Model and Beyond
We present the invited lectures given at the Third IDPASC School which took
place in Santiago de Compostela in January 2013. The students attending the
school had very different backgrounds, some of them were doing their Ph.D. in
experimental particle physics, others in theory. As a result, and in order to
make the lectures useful for most of the students, we focused on basic topics
of broad interest, avoiding the more technical aspects of Flavour Physics and
CP Violation. We make a brief review of the Standard Model, paying special
attention to the generation of fermion masses and mixing, as well as to CP
violation. We describe some of the simplest extensions of the SM, emphasising
novel flavour aspects which arise in their framework.Comment: Invited talk at the Third IDPASC School 2013, January 21st - February
2nd 2013, Santiago de Compostela, Galiza, Spain; 36 pages, 8 figures, 2
tables; version with few misprints correcte
Bounds on gamma from CP violation measurements in B -> pi+ pi- and B -> psi K_S
We study the determination of gamma from CP-violating observables in B -> pi+
pi- and B -> psi K_S. This determination requires theoretical input to one
combination of hadronic parameters. We show that a mild assumption about this
quantity may allow bounds to be placed on gamma, but we stress the pernicious
effects that an eightfold discrete ambiguity has on such an analysis. The
bounds are discussed as a function of the direct (C) and interference (S)
CP-violating observables obtained from time-dependent B -> pi+ pi- decays, and
their behavior in the presence of new physics effects in B-Bbar mixing is
studied. (V2: Misprints corrected. Slightly improved discussion.)Comment: 11 pages, RevTex 4, 5 eps figures include
Seismic performance assessment of a timber log house
The current work presents a full scale shaking table test conducted on a twostoreyed
timber log house, designed according to the state of the art on timber engineering. The
test was performed within the framework of the SERIES Project âMulti-storey timber buildingsâ
at LNEC, Lisbon, Portugal. Several tests and studies have been carried out by the University
of Minho to characterize the behavior of the different components (logs, walls, slabs, connections,
etc.) of log houses in the past few years for the European Technical Approval (ETA)
of this construction system. The main results of the shaking table test are presented along with
the preliminary analysis of the overall behavior of the log house. The analysis was carried out
based on the shaking table tests and on a numerical model developed to estimate the main seismic
parameters using the data obtained from the different individual studies on each component
of the construction system performed within the framework of the ETA
Seismic analysis of a 2-storey log house
The current paper deals with the analysis of the results yielded by a series of tests performed to evaluate the seismic behaviour of a model log construction. The study was based on an experimental investigation performed to improve the existing knowledge on log houses subject to seismic events. The main part of the experimental work is based on a full scale shaking table test, conducted on a two-storey log house designed by the Portuguese company RusticasaÂź in compliance with design rules for timber buildings. The test was performed by the University of Minho within the framework of the SERIES Project âMulti-storey timber buildingsâ and was coordinated by the University of Trento, at LNEC, Lisbon, Portugal.
The geometry of the specimen, the design of the test, the setup and the instrumentation layout are first presented in this paper. The test procedure was conducted in stages with maximum accelerations (bi-directional) of 0.07g, 0.28g and 0.5g. The experimental results of each test have been analyzed and the resultant values of inter-storey drift, wall slippage and uplift measurements, shear deformations and hold-down forces measured are presented. Most importantly, the dynamic properties (fundamental period and mode shapes) of the system have been determined
On fermion masses and mixing in a model with symmetry
In a recently proposed multi-Higgs extension of the standard model in which
discrete symmetries, and are imposed we show that, after
accommodating the fermion masses and the mixing matrices in the charged
currents, the mixing matrices in the neutral currents induced by neutral
scalars are numerically obtained. However, the flavor changing neutral currents
are under control mainly by mixing and/or mass suppressions in the neutral
scalar sector.Comment: Version accepted for publication in International Journal of Modern
Physics A. In this version we added a discussion on the charged lepton and
neutrino masses. The title has been changed. Other minor changes do not
modify the conclusion
Mass matrices and eigenstates for scalars / pseudoscalars; indirect CP violation, mass hierarchies and symmetry breaking
I study indirect CP violation for neutral kaons, and extend it to large
values of the CP-violating parameter (taken to be real). I show how and at
which condition there can exist a continuous set of basis in which the kinetic
and mass terms in the Lagrangian can be diagonalized simultaneously. An
ambiguity results for the mass spectrum, which then depends on the basis. In
particular, for fixed (positive) (mass)^2 of the CP eigenstates K^0_1, K^0_2,
and for certain ranges of values of the CP-violating parameter, a negative
(mass)^2 can arise in the CP-violating basis. Under certain conditions, even a
small perturbation, by lifting the ambiguity, can strongly alter the pattern of
masses. These investigations extend in a natural way to indirect CP violation
among a set of Higgs-like doublets. The C-odd commutator [K^0, K^0 bar], or its
equivalent for Higgs multiplets, plays an important role. The condition for its
vanishing and its consequences are among the main concerns of this work.Comment: LaTeX2e, 35 pages, 10 postscript figures + 1 log
Fundamental CP-violating quantities in a SU(2)U(1) model with many Higgs doublets
We consider a SU(2)U(1) gauge theory with many scalar doublets,
but without fermions. We devise a systematic method of constructing quantities
which are invariant under changes of basis of the scalar fields, but acquire a
minus sign under a general CP transformation. Those quantities provide a
basis-independent way of checking for the existence of CP violation.Comment: (Latex file, 9 pages). CMU-preprin
Sustainability and cultural heritage buildings
[Excerpt from Introduction] Conservation of cultural heritage buildings is a demand from society, which recognizes this heritage as a part of their identity, but it is also an economical issue. In Europe, tourism accounts for 10% of the GDP and 12% of the employment, if linked sectors are considered [x.1]. The EU is the world's number one tourist destination, with 40 % of arrivals in the world and with 7 European countries among the top ten [x.2]. According to the WTO estimates, international tourist arrivals in Europe will increase significantly. The built European heritage, namely monuments or historical centres, is a main attractor for tourism, with 45% of the UNESCO World Heritage sites within the EU. Therefore, the need for their conservation is unquestionable. [...
Orthogonal Higgs bundles with singular spectral curves
We examine Higgs bundles for non-compact real forms of SO(4,C) and the
isogenous complex group SL(2,C)XSL(2,C). This involves a study of non-regular
fibers in the corresponding Hitchin fibrations and provides interesting
examples of non-abelian spectral data.Comment: v3. Minor typos corrected and a dedication added. To appear in CAG in
a special volume in honor of Karen Uhlenbeck's 75th birthda
- âŠ