1,406 research outputs found
Wrong sign and symmetric limits and non-decoupling in 2HDMs
We analyse the possibility that, in two Higgs doublet models, one or more of
the Higgs couplings to fermions or to gauge bosons change sign, relative to the
respective Higgs Standard Model couplings. Possible sign changes in the
coupling of a neutral scalar to charged ones are also discussed. These
\textit{wrong signs} can have important physical consequences, manifesting
themselves in Higgs production via gluon fusion or Higgs decay into two gluons
or into two photons. We consider all possible wrong sign scenarios, and also
the \textit{symmetric limit}, in all possible Yukawa implementations of the two
Higgs doublet model, in two different possibilities: the observed Higgs boson
is the lightest CP-even scalar, or the heaviest one. We also analyse thoroughly
the impact of the currently available LHC data on such scenarios. With all 8
TeV data analysed, all wrong sign scenarios are allowed in all Yukawa types,
even at the 1 level. However, we will show that B-physics constraints
are crucial in excluding the possibility of wrong sign scenarios in the case
where is below 1. We will also discuss the future prospects for
probing the wrong sign scenarios at the next LHC run. Finally we will present a
scenario where the alignment limit could be excluded due to non-decoupling in
the case where the heavy CP-even Higgs is the one discovered at the LHC.Comment: 20 pages, 15 figure
The CP-conserving 2HDM after the 8 TeV run
We confront the most common CP-conserving 2HDM with the LHC data analysed so
far while taking into account all previously available experimental data. A
special allowed corner of the parameter space is analysed - the so-called
wrong-sign scenario where the Higgs coupling to down-type quarks changes sign
relative to the Standard Model while the coupling to the massive vector bosons
does not.Comment: 6 pages, 2 figures, to appear in the proceedings of the 22nd
International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS
2014), 28 April - 2 May 2014 Warsaw (Poland
The Wrong Sign limit in the 2HDM
A sign change in the Higgs couplings to fermions and massive gauge bosons is
still allowed in the framework of two-Higgs doublet models (2HDM). In this work
we discuss the possible sign changes in the Higgs couplings to fermions and
gauge bosons, while reviewing the status of the 8-parameter CP-conserving 2HDM
after the Large Hadron Collider 8 TeV run.Comment: 6 pages, 3 figures. Proceedings of the Second Annual Conference on
Large Hadron Collider Physics, Columbia University, New York, U.S.A, June
2-7, 2014. arXiv admin note: text overlap with arXiv:1407.439
Charge Influence On Mini Black Hole's Cross Section
In this work we study the electric charge effect on the cross section
production of charged mini black holes (MBH) in accelerators. We analyze the
charged MBH solution using the {\it fat brane} approximation in the context of
the ADD model. The maximum charge-mass ratio condition for the existence of a
horizon radius is discussed. We show that the electric charge causes a decrease
in this radius and, consequently, in the cross section. This reduction is
negligible for protons and light ions but can be important for heavy ions.Comment: 4 pages, 0 figure. To be published in Int. J. Mod. Phys. D
ScannerS: parameter scans in extended scalar sectors
We present the public code ScannerS–2 that performs parameter scans and checks parameter points in theories beyond the Standard Model (BSM) with extended scalar sectors. ScannerS incorporates theoretical and experimental constraints from many different sources in order to judge whether a parameter point is allowed or excluded at approximately 95% {CL}. The BSM models implemented in ScannerS include many popular BSM models such as singlet extensions, different versions of the Two-Higgs-Doublet Model, or the different phases of the Next-to Two-Higgs-Doublet Model. The ScannerS framework allows straightforward extensions by additional constraints and BSM models
Two-loop stability of a complex singlet extended Standard Model
Motivated by the dark matter and the baryon asymmetry problems, we analyse a complex singlet extension of the Standard Model (SM) with a Z2 symmetry (which provides a dark matter candidate). After a detailed two-loop calculation of the renormalization group equations for the new scalar sector, we study the radiative stability of the model up to a high energy scale (with the constraint that the 126 GeV Higgs boson found at the LHC is in the spectrum) and find it requires the existence of a new scalar state mixing with the Higgs with a mass larger than 140 GeV. This bound is not very sensitive to the cut-off scale as long as the latter is larger than 10^10 GeV. We then include all experimental and observational constraints/measurements from collider data, dark matter direct detection experiments and from the Planck satellite and in addition force stability at least up to the GUT scale, to find that the lower bound is raised to about 170 GeV, while the dark matter particle must be heavier than about 50 GeV
Implicit Regularization and Renormalization of QCD
We apply the Implicit Regularization Technique (IR) in a non-abelian gauge
theory. We show that IR preserves gauge symmetry as encoded in relations
between the renormalizations constants required by the Slavnov-Taylor
identities at the one loop level of QCD. Moreover, we show that the technique
handles divergencies in massive and massless QFT on equal footing.Comment: (11 pages, 2 figures
Diversidade florística e fitossociológica do tapete herbáceo da caatinga na reserva legal do Salitre, Juazeiro-BA.
Para amostragem das herbáceas foi adotado o método das parcelas, com 50m2 de área amostral em cada microhabitate
Influence of thickness and coatings morphology in the antimicrobial performance of zinc oxide coatings
"Author's copy"In this research work, the production of undoped and silver (Ag) doped zinc oxide (ZnO) thin films for
food-packaging applications were developed. The main goal was to determine the influence of coatings
morphology and thickness on the antimicrobial performance of the produced samples. The ZnO based
thin films were deposited on PET (Polyethylene terephthalate) substrates by means of DC reactive magnetron
sputtering. The thin films were characterized by optical spectroscopy, X-Ray Diffraction (XRD),
X-ray photoelectron spectroscopy (XPS) and Scanning Electron Microscopy (SEM). The antimicrobial
performance of the undoped and Ag-doped ZnO thin films was also evaluated. The results attained have
shown that all the deposited zinc oxide and Ag-doped ZnO coatings present columnar morphology with
V-shaped columns. The increase of ZnO coatings thickness until 200 nm increases the active surface area
of the columns. The thinner samples (50 and 100 nm) present a less pronounced antibacterial activity
than the thickest ones (200–600 nm). Regarding Ag-doped ZnO thin films, it was verified that increasing
the silver content decreases the growth rate of Escherichia coli and decreases the amount of bacteria cells
present at the end of the experiment.The work described in this paper was supported by project NANOPACKSAFER: NANO-engineered PACKaging systems for improving quality, SAFEty and health characteristics of foods, Portugal-Spain International Nanotechnology Laboratory Nanotechnology Projects Call; and also by the FEDER funding through the COMPETE program and FCT PEst-C/BIA/UI4050/2011 project
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