1,194 research outputs found
Primordial Bispectrum Information from CMB Polarization
After the precise observations of the Cosmic Microwave Background (CMB)
anisotropy power spectrum, attention is now being focused on the higher order
statistics of the CMB anisotropies. Since linear evolution preserves the
statistical properties of the initial conditions, observed non-Gaussianity of
the CMB will mirror primordial non-Gaussianity. Single field slow-roll
inflation robustly predicts negligible non-Gaussianity so an indication of
non-Gaussianity will suggest alternative scenarios need to be considered. In
this paper we calculate the information on primordial non-Gaussianity encoded
in the polarization of the CMB. After deriving the optimal weights for a cubic
estimator we evaluate the Signal-to-Noise ratio of the estimator for WMAP,
Planck and an ideal cosmic variance limited experiment. We find that when the
experiment can observe CMB polarization with good sensitivity, the sensitivity
to primordial non-Gaussianity increases by roughly a factor of two. We also
test the weakly non-Gaussian assumption used to derive the optimal weight
factor by calculating the degradation factor produced by the gravitational
lensing induced connected four-point function. The physical scales in the
radiative transfer functions are largely irrelevant for the constraints on the
primordial non-Gaussianity. We show that the total (S/N)^2 is simply
proportional to the number of observed pixels on the sky.Comment: To be submitted to PRD, 25 pages, 6 figure
Contact interaction probes at the Linear Collider with polarized electron and positron beams
For contact-interaction searches at the Linear Collider, we discuss the
advantages of polarizing both the electron and the positron beams as compared
with polarizing only the electron beam. In particular, for the processes
e^+e^-\to \mu^+\mu^-, \tau^+\tau^-, b\bar{b} and c\bar{c} at a future e^+e^-
collider with \sqrt{s}=0.5 TeV we derive model-independent bounds on the
four-fermion contact interaction parameters from studies of the helicity cross
sections.Comment: 1+15 pages, LaTeX2e, including 7 figure
New physics signatures at a Linear Collider: model-independent analysis from `conventional' polarized observables
We discuss four-fermion contact-interaction searches in the processes
e^+e^-\to\mu^+\mu^-, c{\bar c} and b{\bar b} at a future e^+e^- Linear Collider
with c.m. energy \sqrt{s}=0.5 TeV and with both beams longitudinally polarized.
Our analysis is based on the measurements of familiar polarized observables
such as the total cross section and the forward-backward/left-right
asymmetries, and accounts for the general set of contact interaction couplings
as independent, non-zero, parameters thus avoiding simplifying,
model-dependent, assumptions. We derive the corresponding model-independent
constraints on the above-mentioned coupling constants, and evaluate the
corresponding reach at the Linear Collider, emphasizing the role of beam
polarization. We compare the results with a model-dependent procedure where
only one coupling is varied at a time.Comment: 13 pages, including 3 figure
Название статьи: снижение выбросов парниковых газов через управление отходами производства
В настоящее время население мира растет очень быстро. Такой рост населенияспособствует высокому загрязнению окружающей среды. Сжигание углеводородного топливанеизбежно ведет к накоплению в атмосфере углекислого газа и усилению парникового эффекта.Цель исследования заключалась в оценке возможности использования в производственном циклевторичной переработки использованных ПЭТ бутылок как варианта утилизации отходов, которыйможет существенно уменьшить экологические проблемы, связанные с отходами пластиковых бутылок.Количество парниковых газов может быть сокращено за счет отказа от захоронения и сжигания впользу переработки. Переработка является экологически более предпочтительной для утилизации ПЭТ продуктов
Contact interactions and polarized beams at a Linear Collider
We discuss contact-interaction searches in the processes e^+e^-\to
\mu^+\mu^-, b\bar{b} and c\bar{c} at an e^+e^- Linear Collider with c.m. energy
\sqrt{s}=0.5 TeV and with longitudinally polarized beams. The measurement of
polarized cross sections allows to study the individual helicity cross
sections, and consequently to derive separate, model-independent, constraints
on the four-fermion contact interaction couplings. We evaluate the reach on
those parameters foreseeable in the case of both electron and positron
polarization fixed at some reference values, and compare it with the situation
where only electron polarization is available. The analysis is based on
polarized integrated cross sections with optimal kinematical cuts that can
improve the sensitivity to the relevant couplings. While electron polarization
would by itself allow such an analysis, the additional positron polarization
(with no loss of beam intensity) and optimization can have a crucial role in
improving the sensitivity to the new interactions.Comment: 13 pages, LaTeX, including figure
Model-independent limits on four-fermion contact interactions at LC with polarization
Fermion compositeness, and other types of new physics that can be described
by the exchange of very massive particles, can manifest themselves as the
result of an effective four-fermion contact interaction. In the case of the
processes and at future
colliders with TeV, we examine the sensitivity to
four-fermion contact interactions of two new integrated observables,
and , conveniently defined for such kind of analysis. We find that,
if longitudinal polarization of the electron beam were available, these
observables would offer the opportunity to separate the helicity cross sections
and, in this way, to derive model-independent bounds on the relevant
parameters.Comment: 13 pages, LaTe
Excitation model of cardiac p cells of the cardiac conduction system
The article considers elaboration of the mathematical model of cardiac electrical activity which will allow investigating excitation propagation processes at all sites of the cardiac conduction system. The proposed model is generated on the basis of parametric elements of an electric circuit with distributed parameters and approximation of time dependencies of conduction in ion channels by cubic splines
Visualization of the heart with help of cardiographic equipment
This study presents the problems associated with cardiovascular diseases (CVD) and Twocomponent FitzHugh - Nagumo model and heart condition imaging algorithm are considered. Aspects of work aimed at designing and developing of the hardware and software complex based on the information obtained with the help of an electrocardiograph
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