18 research outputs found
A Short Guide to Flavour Physics and CP Violation
We present the invited lectures given at the second Asia-Europe-Pacific
School of High-Energy Physics (AEPSHEP), which took place in Puri, India in
November 2014. The series of lectures aimed at graduate students in particle
experiment/theory, covering the very basics of flavor physics and CP violation,
some useful theoretical methods such as OPE and effective field theories, and
some selected topics of flavour physics in the era of LHC.Comment: 51 pages, 19 figures, paper submitted for publication in a CERN
Yellow Report (YR
CP4 miracle: shaping Yukawa sector with CP symmetry of order four
We explore the phenomenology of a unique three-Higgs-doublet model based on
the single CP symmetry of order 4 (CP4) without any accidental symmetries. The
CP4 symmetry is imposed on the scalar potential and Yukawa interactions,
strongly shaping both sectors of the model and leading to a very characteristic
phenomenology. The scalar sector is analyzed in detail, and in the Yukawa
sector we list all possible CP4-symmetric structures which do not run into
immediate conflict with experiment, namely, do not lead to massless or
mass-degenerate quarks nor to insufficient mixing or CP-violation in the CKM
matrix. We show that the parameter space of the model, although very
constrained by CP4, is large enough to comply with the electroweak precision
data and the LHC results for the 125 GeV Higgs boson phenomenology, as well as
to perfectly reproduce all fermion masses, mixing, and CP violation. Despite
the presence of flavor changing neutral currents mediated by heavy Higgs
scalars, we find through a parameter space scan many points which accurately
reproduce the kaon CP-violating parameter as well as oscillation
parameters in K and mesons. Thus, CP4 offers a novel minimalistic
framework for building models with very few assumptions, sufficient predictive
power, and rich phenomenology yet to be explored.Comment: 39 pages, 8 figures, 1 table; v2: expanded discussion, extra
references, matches published versio
Singlets in Composite Higgs Models in light of the LHC di-photon searches
Models of compositeness can successfully address the origin of the Higgs
boson, as a pseudo Nambu Goldstone boson (pNGB) of a spontaneously broken
global symmetry, and flavour physics via the partial compositeness mechanism.
If the dynamics is generated by a confining gauge group with fermionic matter
content, there exists only a finite set of models that have the correct
properties to account for the Higgs and top partners at the same time. In this
letter we explore the theory space of this class of models: remarkably, all of
them contain - beyond the pNGB Higgs - a pNGB singlet, , which couples to
Standard Model gauge bosons via Wess-Zumino-Witten interactions, thus providing
naturally a resonance in di-boson at the LHC. With the assumption that the
recently reported di-photon excess at 750 GeV at the LHC arises from the
a-resonance, we propose a generic approach on how to delineate the best
candidate for composite Higgs models with top-partners. We find that
constraints from other di-boson searches severely reduce the theory space of
the models under consideration. For the models which can explain the di-photon
excess, we make precise and testable predictions for the width and other
di-boson resonance searches.Comment: 5 pages, 2 Tables; v2: clarifying comments added, typos fixed,
references update
Anarchic Yukawas and top partial compositeness: the flavour of a successful marriage
The top quark can be naturally singled out from other fermions in the
Standard Model due to its large mass, of the order of the electroweak scale. We
follow this reasoning in models of pseudo Nambu Goldstone Boson composite
Higgs, which may derive from an underlying confining dynamics. We consider a
new class of flavour models, where the top quark obtains its mass via partial
compositeness, while the lighter fermions acquire their masses by a deformation
of the dynamics generated at a high flavour scale. One interesting feature of
such scenario is that it can avoid all the flavour constraints without the need
of flavour symmetries, since the flavour scale can be pushed high enough. We
show that both flavour conserving and violating constraints can be satisfied
with top partial compositeness without invoking any flavour symmetry for the
up-type sector, in the case of the minimal SO(5)/SO(4) coset with top partners
in the four-plet and singlet of SO(4). In the down-type sector, some degree of
alignment is required if all down-type quarks are elementary. We show that
taking the bottom quark partially composite provides a dynamical explanation
for the hierarchy causing this alignment. We present explicit realisations of
this mechanism which do not require to include additional bottom partner
fields. Finally, these conclusions are generalised to scenarios with
non-minimal cosets and top partners in larger representations.Comment: 37 pages, 1 figure, v2: typos fixed, Eq. (3.44) added, version
corresponds to published article in JHE
Reabilitação do Centro de Saúde de Sete Rios, do Ministério da Saúde
Relatório de Estágio para obtenção do grau de Mestre em Engenharia Civil Perfil de EdificaçõesO presente Trabalho Final de Mestrado tem como objetivo descrever as atividades desenvolvidas ao longo da realização de um estágio curricular na Administração Regional de Saúde de Lisboa e Vale do Tejo, no âmbito do Mestrado em Engenharia Civil, perfil de Edificações, no Instituto Superior de Engenharia de Lisboa (ISEL).
No relatório são descritas as atividades desenvolvidas no período de seis meses em que se realizou o estágio, evidenciando as características do edifício em estudo, o Centro de
Saúde de Sete Rios, em Lisboa e as patologias existentes no mesmo, o modo como serão corrigidas e as soluções alternativas e necessárias para manter o edifício em boas condições de utilização.
Salienta-se também o trabalho desenvolvido na elaboração da documentação técnica que consta da proposta para a realização da empreitada de conservação do edifício e na elaboração de melhorias ao Método de Avaliação do Estado de Conservação de Edifícios, utilizado pelos técnicos da entidade em que foi realizado o estágio, de modo a torná-lo mais adequado para avaliar o estado de conservação de edifícios de saúde.Abstract: This Final Thesis aims to describe the activities developed during the internship at the ARSLVT,IP (Administração Regional de Saúde de Lisboa e Vale do Tejo), under a protocol signed between ARSLVT,IP and ISEL – Instituto Superior de Engenharia de Lisboa.
This document describes the activities carried out within the six months internship: the characterization of the case study building, the “Sete Rios Health Center”, in Lisbon, the study of the existing conditions, the accurate study of the building pathologies, the way to correct those pathologies and the approach to a basic maintenance plan.
The present document includes the preparation of the technical documentation which will integrate the bid process in order to repair the building pathologies. A revision of the Assessment Method to evaluate the conservation status of the building was additionally produced, therefore allowing the technical staff of ARSLVT to develop their activities
based on a much more accurate documentation. The revision of the Assessment Method was focused on the conservation of service health buildings
Baryogenesis through split Higgsogenesis
We study the cosmological evolution of asymmetries in the two-Higgs doublet extension of the Standard Model, prior to the electroweak phase transition. If Higgs flavour-exchanging interactions are sufficiently slow, then a relative asymmetry among the Higgs doublets corresponds to an effectively conserved quantum number. Since the magnitude of the Higgs couplings depends on the choice of basis in the :Higgs doublet space, we attempt to formulate basis-independent out-of-equilibrium conditions. We show that an initial asymmetry between the fliggs scalars, which could be generated by GP violation in the :Higgs sector, will be transformed into a baryon asymmetry by the sphalerons, without the need of B ¿ L violation. This novel mechanism of baryogenesis through (split) Higgsogenesis is exemplified with simple scenarios based on the out-of-equilibrium decay of heavy singlet scalar fields into the illiggs doublets
Classification of anomaly-free 2HDMs with a gauged U (1)′ symmetry
Two-Higgs-doublet models (2HDMs) with a flavored U(1)′ gauge symmetry are a popular extension to the Standard Model (SM), yet they currently lack a complete survey. In this paper, we present a full classification of anomaly-free 2HDMs within the SM fermion content, resulting in a total of 11 distinct models. Four of these are relatively well studied, while the rest either partially, or entirely, lack previous treatment. We study these textures under a variety of experimental bounds, focusing mainly on the previously unexplored models. This work is intended to act as a catalog to models worth considering in greater detail