14,819 research outputs found
Extended Modified Observable Technique for a Multi-Parametric Trilinear Gauge Coupling Estimation at LEP II
This paper describes the extension of the Modified Observables technique in
estimating simultaneously more than one Trilinear Gauge Couplings. The optimal
properties, unbiasedness and consistent error estimation of this method are
demonstrated by Monte Carlo experimentation using four-fermion
final state topologies. Emphasis is given in the determination of the expected
sensitivities in estimating the and
pair of couplings with data from the 183
GeV LEPII run.Comment: (17 pages, 8 figures
Multidimensional Binning Techniques for a Two Parameter Trilinear Gauge Coupling Estimation at LEP II
This paper describes two generalization schemes of the Optimal Variables
technique in estimating simultaneously two Trilinear Gauge Couplings. The first
is an iterative procedure to perform a 2-dimensional fit using the linear terms
of the expansion of the probability density function with respect to the
corresponding couplings, whilst the second is a clustering method of
probability distribution representation in five dimensions. The pair production
of W's at 183 GeV center of mass energy, where one W decays leptonically and
the other hadronically, was used to demonstrate the optimal properties of the
proposed estimation techniques.Comment: (25 pages, 11 figures
Model independent constraints on contact interactions from LEP2
We quantitatively discuss the possibility of deriving model-independent
constraints on the general four-fermion contact interaction couplings, from the
currently available data on the two-fermion production processes
, and with unpolarized initial
beams. The method is essentially based on particular, simple, combinations of
the measured total cross section and forward-backward asymmetry that allow
partial separation of the helicity cross sections, and the combination of
experimental data obtained at the different energies of TRISTAN, LEP1 and LEP2.Comment: 9 pages (Latex) with 6 figures and 1 tabl
Update on tests of the Cen A neutron-emission model of highest energy cosmic rays
We propose that neutron emission from Cen A dominates the cosmic ray sky at
the high end of the spectrum. Neutrons that are able to decay generate proton
diffusion fronts, whereas those that survive decay produce a spike in the
direction of the source. We use recent data reported by the Pierre Auger
Collaboration to normalize the injection spectrum and estimate the required
luminosity in cosmic rays. We find that such a luminosity, L_{CR} ~ 5 x 10^{40}
erg/s, is considerably smaller than the bolometric luminosity of Cen A, L_{bol}
~ 10^{43} erg/s. We compute the incoming current flux density as viewed by an
observer on Earth and show that the anisotropy amplitude is in agreement with
data at the 1\sigma level. Regardless of the underlying source model, our
results indicate that after a decade of data taking the Pierre Auger
Observatory will be able to test our proposal.Comment: To be published in PR
Percolation approach to quark gluon plasma in high energy pp collisions
We apply continuum percolation to proton-proton collisions and look for the
possible threshold to phase transition from confined nuclear matter to quark
gluon plasma. Making the assumption that J/Psi suppression is a good signal to
the transition, we discuss this phenomenon for pp collisions, in the framework
of a dual model with strings.Comment: 8 pages, 3 figure
Beam-Beam with a few long range encounters at short distance
The high nominal luminosity of the LHC requires a large number of bunches spaced by about 25 ns. To prevent more than one head-on collision in each interaction region, a total crossing angle of 0.285 mrad is necessary, and the bunches experience around 30 long range (LR) interactions per IP with at mean separation of 9.5 s. For the LHC luminosity upgrade, there are two possible scenarios: the early separation scheme and low Piwinski angle (LPA) scheme. In the early separation scheme, a few long range interactions need to be tolerated, this paper the discuss the possibility of having a few LR encounters at a minimum separation smaller than the 9 s, and present observations from other hadron machines with a smaller beam separation
A arte de controle do estresse calórico em aves.
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