9,478 research outputs found
The Effect of Composite Resonances on Higgs decay into two photons
In scenarios of strongly coupled electroweak symmetry breaking, heavy
composite particles of different spin and parity may arise and cause observable
effects on signals that appear at loop levels. The recently observed process of
Higgs to at the LHC is one of such signals. We study the new
constraints that are imposed on composite models from ,
together with the existing constraints from the high precision electroweak
tests. We use an effective chiral Lagrangian to describe the effective theory
that contains the Standard Model spectrum and the extra composites below the
electroweak scale. Considering the effective theory cutoff at TeV, consistency with the and parameters and the newly
observed can be found for a rather restricted range of
masses of vector and axial-vector composites from TeV to TeV and
TeV to TeV, respectively, and only provided a non-standard kinetic
mixing between the and fields is included.Comment: 30 pages, 10 figures. Version for publication in European Physical
Journal
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Composite polymer membranes for laserinduced fluorescence thermometry
We demonstrate a modified version of laser-induced fluorescence thermometry (LIFT) for mapping temperature gradients in the vicinity of small photothermal devices. Our approach is based on temperature sensitive fluorescent membranes fabricated with rhodamine B and polydimethylsiloxane (PDMS). Relevant membrane features for LIFT, such as temperature sensitivity, thermal quenching and photobleaching are presented for a range of 25 °C to 90 °C, and their performance is evaluated upon obtaining the temperature gradients produced in the proximity of optical fiber micro-heaters. Our results show that temperature measurements in regions as small as 750 μm x 650 μm, with a temperature resolution of 1 °C, can be readily obtained
A Characterization of concave mappings
This study focuses on Concave mappings, a class of univalent functions that
exhibit a unique property: they map the unit disk onto a domain whose
complement is convex. The main objective of this work is to characterize these
mappings in terms of the real part of the expression ,
considering scenarios where the omitted convex domain is either bounded or
unbounded. In the case of a bounded convex domain, we investigate the pivotal
role played by the Schwarzian derivative and the order of the functions in
understanding the behavior and properties of these mappings
Analysis of the quark sector in the 2HDM-III with a four-zero Yukawa texture using the most recent data on the CKM matrix
In this letter we analyse, in the context of the general 2-Higgs Doublet
Model, the structure of the Yukawa matrices, , by assuming a four-zero texture ansatz for their definition. In this
framework, we obtain compact expressions for , which are reduced to the Cheng and Sher ansatz with the difference that
they are obtained naturally as a direct consequence of the invariants of the
fermion mass matrices. Furthermore, in order to avoid large flavour violating
effects coming from charged Higgs exchange, we consider the main flavour
constraints on the off-diagonal terms of Yukawa texture {{}} (). We perform a -fit
based on current experimental data on the quark masses and the
Cabibbo-Kobayashi-Maskawa mixing matrix . Hence, we obtain
the allowed ranges for the parameters at
1 for several values of . The results are in complete
agreement with the bounds obtained taking into account constraints on Flavour
Changing Neutral Currents reported in the literature.Comment: 12 pages, 1 figure. Version accepted in Phys. Lett.
Phase diagram of silicon from atomistic simulations
In this letter we present a calculation of the temperature-pressure phase
diagram of Si in a range of pressures covering from -5 to 20 GPa and
temperatures up to the melting point. The phase boundaries and triple points
between the diamond, liquid, -Sn and clathrate phases are
reported. We have employed efficient simulation techniques to calculate free
energies and to numerically integrate the Clausius-Clapeyron equation, combined
with a tight binding model capable of an accuracy comparable to that of
first-principles methods. The resulting phase diagram agrees well with the
available experimental data.Comment: 5 pages, 1 figure, accepted in PR
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