3,383 research outputs found
Measurements of \gamma \gamma \to \mbox{Higgs} and in collisions at the Future Circular Collider
The measurements of the two-photon production of the Higgs boson and of
boson pairs in collisions at the Future Circular
Collider (FCC-ee) are investigated. The processes
are computed using the effective photon approximation for electron-positron
beams, and studied in their and
decay final-states including parton showering and hadronization, jet
reconstruction, forward tagging, and realistic experimental cuts. After
selection criteria, up to 75 Higgs bosons and 6600 pairs will be
reconstructed on top of controllable continuum backgrounds at 240
and 350 GeV for the total expected integrated luminosities, by tagging the
scattered with near-beam detectors. A 5 observation of H is thereby warranted, as well as high-statistics studies of triple
and quartic electroweak couplings,
improving by at least factors of 2 and 10 the current limits on dimension-6
anomalous quartic gauge couplings.Comment: Presented at EDS Blois 2017 Conference , Prague, Czech Republic, June
26--30, 201
Prospects for Higgs observation in ultraperipheral ion collisions at the Future Circular Collider
We study the two-photon production of the Higgs boson, , at the Future Circular Collider (FCC) in ultraperipheral PbPb and pPb
collisions at and 63 TeV. Signal and background events are
generated with MADGRAPH 5, including fluxes from the proton and lead
ions in the equivalent photon approximation, yielding = 1.75 nb and 1.5 pb in PbPb and pPb collisions
respectively. We analyse the H decay channel including
realistic reconstruction efficiencies for the final-state -jets, showered
and hadronized with PYTHIA 8, as well as appropriate selection criteria to
reduce the dominant exclusive continuum background.
Observation of is achievable
in the first year with the expected PbPb integrated luminosities.Comment: 5 pages, 4 figures. PHOTON'17, CERN Proceedings, to appear.
References adde
Higgs boson production in photon-photon interactions with proton, light-ion, and heavy-ion beams at current and future colliders
The production of the Higgs boson in photon-photon interactions with proton
and nucleus beams at three planned or proposed future CERN colliders --- the
high-luminosity Large Hadron Collider (HL-LHC), the high-energy LHC (HE-LHC),
and the Future Circular Collider (FCC) --- is studied. The cross sections for
the process AA(A)H(A), with the ions A surviving
the interaction and the Higgs scalar exclusively produced, are computed with
MadGraph 5 modified to include the corresponding elastic fluxes, for
Pb-Pb, Xe-Xe, Kr-Kr, Ar-Ar, O-O, p-Pb, and p-p over the nucleon-nucleon
collision energy range --100 TeV. Simulations of the
decay mode --- including realistic
(mis)tagging and reconstruction efficiencies for the final-state b-jets, as
well as appropriate kinematical selection criteria to reduce the similarly
computed continuum backgrounds ---
have been carried out. Taking into account the expected luminosities for all
systems, the yields and significances for observing the Higgs boson in
ultraperipheral collisions (UPCs) are estimated. At the HL-LHC and HE-LHC, the
colliding systems with larger Higgs significance are Ar-Ar(6.3 TeV) and
Kr-Kr(12.5 TeV) respectively, but evidence for two-photon Higgs
production would require 200 and 30 times larger integrated luminosities than
those planned today at both machines. Factors of ten can be gained by running
for a year, rather than the typical 1-month heavy-ion LHC operation, but the
process will likely remain unobserved until a higher energy hadron collider,
such as the FCC, is built. In the latter machine, the observation of
Higgs production in UPCs is feasible in just the first nominal run of Pb-Pb and
p-Pb collisions at and 63 TeV respectively.Comment: 8 pages, 4 figures. Minor mods. to match final PRD versio
Illuminating the charged leptons in the proton
The description of the structure of proton is fundamental in order to
describe the standard model processes at the LHC as well as for the searching
of New Physics. Quantum fluctuations imply the presence of photons and leptons
inside the proton, which admit a parton distribution function (PDF). Although
the lepton PDFs are expected to be small, its presence opens new production
mechanisms. In order to explore the lepton - induced processes at the LHC, a
precise determination of the leptonic content of the proton is needed. In this
paper we propose to constrain the content of charged leptons inside the proton
through the study of the QED Compton scattering in ultraperipheral proton -
nucleus collisions at the LHC. We estimate the total cross sections and
associated distributions considering different models for the lepton PDFs and
distinct lepton flavours. We demonstrate that a future experimental analysis of
this process is feasible and that it can be used to constrain the content of
electrons, muons and taus inside the proton.Comment: 10 pages, 3 figures, 1 table. Improved version to be published in PR
Exclusive dilepton production at forward rapidities in collisions
The dilepton production in diffractive and exclusive processes at forward
rapidities considering ultraperipheral collisions at the LHC is
investigated. Predictions for the , and
cross sections are presented taking into account of realistic cuts that can be
implemented by the LHCb Collaboration in a future experimental analysis. Our
results indicate that the background associated with the diffractive production
can be strongly suppressed and the exclusive processes can be cleanly
separated. For the production, the semi and purely leptonic
decay channels are considered. Our results indicate that a future experimental
analysis of the dilepton production at the LHCb is feasible and can be useful
to search for BSM physics.Comment: 7 pages, 3 figures, 3 table
Coherent and incoherent photoproduction in collisions at the LHC, HE -- LHC and FCC
The coherent and incoherent photoproduction in collisions are
investigated considering the possible states of nucleon configurations in the
nuclear wave function and taking into account of the non - linear corrections
to the QCD dynamics. The cross sections and the rapidity and transverse
momentum distributions are estimated for the energies of the next run of the
LHC, High -- Energy LHC and Future Circular Collider. Our results indicate that
a future experimental analysis of these processes will be useful to
discriminate between different approaches for the QCD dynamics as well to
improve our description of the gluon saturation effects.Comment: 7 pages, 3 figures, 1 tabl
Searches for axion-like particles via fusion at future colliders
Opportunities for searches for axion-like particles (ALPs) coupling to
photons in collisions at the Future Circular
Collider (FCC-ee) and International Linear Collider (ILC) are investigated. We
perform a study of the photon-fusion production of ALPs decaying into two
photons, , over the light-by-light
continuum background, for the planned FCC-ee and ILC center-of-mass energies
and integrated luminosities. An analysis of the feasibility measurements is
presented using parametrized simulations for two types of detectors. Upper
limits at 95% confidence level (CL) on the cross section for ALP production,
, and on the ALP-photon coupling
are obtained over the --1000 GeV ALP mass range, and compared
to current and future collider searches. Production cross sections down to
fb (1 ab) will be
probed at (300) GeV, corresponding to constraints on the
axion-photon coupling as low as TeV
Top quark pair production in the exclusive processes at LHC
We analyze the LHC prospects for measurements of the pair produced
exclusively in photon-photon or semi-exclusively in photon-Pomeron and
Pomeron-Pomeron processes using protons tagged in forward proton detectors on
both sides of the interaction point. These processes are interesting from the
point of view of a possible measurement of the top quark mass and constraining
models used in Beyond Standard Model physics. Focusing on the semi-leptonic
channel, , making use of the exclusive
nature of the final state, together with the use of timing information provided
by forward proton detectors, relevant exclusive and inclusive backgrounds are
studied in detail for different luminosity (or pile-up) scenarios and found to
be important for further considerations. For each of these scenarios, we try to
estimate the precision of the top quark mass determination and conclude that
statistical significances need to be significantly enlarged for these processes
to become competitive with measurements of inclusive production.Comment: 17 pages, 5 figure
Avaliação de desempenho de fundos de investimento do setor imobiliário, no mercado uuropeu, em diferentes fases do mercado
Dissertação de mestrado em FinançasA atividade económica ligada ao setor imobiliário Europeu tem crescido imenso e assumido um grande peso nas rendibilidades obtidas pelos investidores, pelo que se torna cada vez mais relevante avaliar o desempenho deste setor. Esta dissertação vem colmatar a escassez de estudos nesta área através da avaliação de desempenho de Fundos de Investimento do Setor Imobiliário no mercado Europeu.
O principal objetivo desta dissertação é avaliar a capacidade de os gestores obterem rendibilidades superiores ao mercado e adicionalmente verificar se o mercado acionista do setor imobiliário Europeu gera rendibilidades superiores ao mercado acionista geral Europeu. Para tal, foram avaliados 47 fundos para o perÃodo de Janeiro de 2003 a Dezembro de 2014 com recurso a metodologias condicionais.
Os resultados comprovam a pertinência da utilização de um benchmark setorial no estudo de fundos especializados, assim como o poder explicativo do fator de risco momentum para o mercado acionista do setor imobiliário. Relativamente à utilização de variáveis de informação pública, nomeadamente, a taxa de juro de longo prazo e a taxa de inflação, não se revelaram estatisticamente significativas na explicação nem das rendibilidades nem do risco.
Por fim, no que concerne ao desempenho dos fundos, não foram encontradas evidências estatisticamente significativas de rendibilidades anormais relativamente ao mercado, para nenhuma das metodologias utilizadas. Podemos concluir que os gestores não demonstram a capacidade de acrescentar valor às suas carteiras através de uma gestão ativa.
Relativamente ao mercado acionista geral Europeu, são encontrados alfas em perÃodos de não-crise estatisticamente significativos e positivos e alfas em perÃodos de crise estatisticamente significativos e negativos para a carteira média, sendo que, os ganhos em perÃodos de não-crise são percentualmente inferiores à s perdas em perÃodos de crise.The economic activity linked to the European real estate sector has grown and taken a great weight in returns obtained by investors. Thus, it is important to evaluate the performance of this sector. This work fills the gap of the shortage of studies in this area by evaluating the performance of the Real Estate Industry Investment Funds in the European market.
The main objective of this dissertation is to evaluate the ability of managers to obtain higher returns than the market and further, verify if the equity market of the European real estate sector generates returns above the general European equity market. To this end, 47 investment funds of the European real estate sector were evaluated for the period from January 2003 to December 2014 using conditional methodologies.
The results show the relevance of using an industry benchmark in the performance evaluation of specialized funds as well as the explanatory power of the momentum risk factor for the real estate equity market. Regarding the use of public information variables, namely, the long-term interest rate and the inflation rate, these variables were not statistically significant in explaining neither the performance nor risk.
Finally, regarding the performance of the funds, there were no statistically significant evidence of abnormal returns relative to the market for any of the methodologies. We can conclude that the fund managers do not show the ability to add value to their portfolios through active management.
Regarding the general European equity market, we find non-crisis alphas statistically significant and positive and crisis alphas statistically significant and negative for the average portfolio, although the gains in periods of non-crisis were lower than the losses in periods of crisis
Reparação de taipa com caldas à base de terra e cal hidraúlica
Este artigo apresenta um programa experimental dedicado à avaliação do desempenho de uma calda de terra e de uma calda comercial, à base de cal hidráulica, na reparação de fendas em paredes de taipa. Foram executados ensaios de compressão diagonal em muretes de taipa, que foram reensaiados após reparação com a injeção das caldas. As caldas apresentaram uma eficiência de reparação semelhante.This paper presents an experimental program on the assessment of the performance of a mud grout and of a commercial hydraulic lime grout in the repair of cracks in rammed earth walls. Diagonal compression tests were conducted on rammed earth wallets, which were retested after repairing with the injection of the grouts. The grouts presented similar repair efficiency.Este trabalho foi financiado por fundos do FEDER através do Programa Operacional Fatores de Competitividade - COMPETE e por fundos nacionais através da Fundação para Ciência e a Tecnologia - FCT no âmbito do projeto POCI-01-0145-FEDER-007633, POCI-01-0145FEDER-016737 (PTDC/ECM-EST/2777/2014) e da bolsa de pós-doutoramento SFRH/BPD/97082/2013. Os autores agradecem o financiamento concedido
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